Been lurking around the forums for awhile... Quite often I will search something on google and I will end up here. Figured I'd join to ask a more specific question that I haven't really found a specific answer for.

I just picked up my first hand gun, a S&W 586. I'd like to get into reloading the ammo for this thing right off the hop. I'm pretty new to reloading, but my understanding for rifle cartridges is that the case length, OAL, and powder grains are tightly woven together to get a safe and pristine round.

For hand gun ammo, from what I have read, that doesn't seem to be the case. For hand gun ammo without a emphasis on max loads the consensus seems to be clean it - or not, check for length - or not, de prime, re-size - check length - or not, prime, powder, seat the bullet to the crimp groove, check for OAL to not be over max, slap it in the chamber and pull the trigger.

But... that seems a little too inconsistent, and not specific enough to me.

I have a Lee die set for 38spl and the card that it came with for load data is fairly vague.

For example:
38 spl case, 158gr Lead Bullet;
Start charge 4.1 Gr Unique. No mention of case length. No mention of OAL.
Max charge 4.7 Gr Unique. No mention of case length. Min OAL 1.440"

38 spl case specs are 1.135" to 1.155". Max OAL is 1.550".

Does that mean I can take a 158 Gr Lead SWC, put 4.1 Gr of Unique in a 1.135" case, stuff the bullet down to the crimp groove, and safely fire it?
Or, put 4.6 Gr of Unique in a 1.135" case, stuff the bullet down to the crimp groove and safely fire it?
Or, put 4.7 Gr of Unique in the case, and only stuff the bullet down until the OAL is greater or equal to 1.440"?

Though to use the crimp groove on the bullet for the 4.7 Gr charge, the case length would have to be taken into consideration so it lines up with a 1.440 or greater OAL.

From my reading on the internet, a 4.7 Gr charge of Unique under a 158 Gr SWC is not a max charge - Though, when I read someone puts 5.0 Gr Unique under a 158 SWC, they may have a specific case length and OAL they are using.

Say I have 50 cases. 10 are 1.135", 10 are 1.140", 10 are 1.145", 10 are 1.150 and 10 are 1.155". And I put 4.1 Gr of Unique in each case, and I put bullets in each of them until the groove. Each of the groups of 10 rounds will have inconsistent OAL, will be consistently in the groove, will have different pressure and velocity, and will be inconsistent on paper.

Say I take the same 50 cases in those case group lengths with 4.1 Gr of Unique, and leave the bullet seating die to seat to the same depth. Each group will be consistent OAL, have inconsistent crimps in relation to the groove, have different pressure and velocity, and be inconsistent on paper.

I recently picked up a mixed head stamp batch of a couple times fired brass in good condition. Picking them out without paying attention to the head stamp, my measurements were anywhere from the min to the max case length. So if I loaded some rounds based on the internets opinion of not checking pistol brass lengths, I'd end up with a scenario like my 10 round groups of mismatched, inconsistent rounds.

Naturally I want to sort the brass, or make them all the same length, or bin all the brass shorter than 1.45 and trim anything greater than 1.45 to 1.45, then develop a charge for that length that puts the crimp in the groove. Which is pretty anal - compared to what I am reading on the web.

So how anal is too anal? Will each of the groups of 10 hit a 10" gong at 25 yards or is that much of a variance going to make for some highly inaccurate ammunition? Do I just start cranking rounds out if they are within the .020" case length window or do I meticulously measure case lengths and develop a charge load around a certain case length? .020" variance in precision rifle round world would be missing left right and center at good distance.

That turned into a novel pretty quick. Thanks for reading if you have made it this far

If you haven't already, you need to invest in a few reloading manuals. Most will give you the MAX cartridge case length and also a TRIM TO LENGTH. Revolver cartridges will need consistent case lengths, in order to get consistent crimps on all cases.

When shooting PPC competition years ago, I separated my range/practice brass, from my competition brass; I was meticulous in keeping my competition brass cleaned and trimmed for maximum accuracy from my gun.

There's a lot of good information here on the Forum, but if you're just getting into reloading, you need to invest in good reloading manuals; which will also have a reloading section to help you get started.

Forget the internet. As previously said, get a good manual, trim your cases to the same length and use the recommended starting load.

The key to making good ammo is consistency. You probably don't need to weigh each case and measure the volume. You probably don't even need to sort by head stamp. You probably don't need to measure and weigh each projectile. But you could do all that, if you wanted the most accurate ammo possible.

But checking case length is a basic step you should do.

You already know you need consistent case length to get a consistent crimp. It becomes critical as you approach maximum loads.

Check your case length on subsequent reloadings. You will find straight walled cases tend not to grow too much and don't need trimming very often. At some point you'll decide, based on your own experience, how often you need to check case lengths.

I don't think I've measured a straight walled pistol case in decades and I've never trimmed one.Start with the minimum charge or maybe a bit more and seat the bullet to the crimp groove.Use the data that matches your bullet by weight,style and composition.I usually find that my best groups have a powder charge about half way between the minimum and maximum listed.
When/if you get into serious competition,that's the time to become anal if you like.For now,just focus on creating safe loads and have fun with it!

As noted previously you really need to have some reloading manuals on hand. The Lee 2nd is a very good source for load data from multiple sources and I've found the Hornady manual is a great source for some of my most accurate loads. However, manuals published by the bullet manufacturers naturally only feature that manufacturer's bullets. The Lyman 49th is also quite good and the Speer #14 is also quite useful.

You also need a good balance beam scale, because it's been my experience that the cheaper digital scales all have a zero setting that wanders due to "drift" in the electrical circuit. Take my word for it, it is no fun at all to discover that gee whiz digital scale "lost" it's zero setting sometime in the process of charging 50 cases and is now 0.2 grains off. Meaning you have to dump that powder in all 50 cases back into the bottle and start over. I've tried the Lee Safety Scale and while it will work saying that it's much too fiddly to set up is actually understating it, it is a royal PITA to get set for a specific weight and the weight that zeros the scale can shift if exposed to any vibration. I would advise you go straight to the RCBS 502, while bit more than double the price of the Lee at 65 dollars it won't break the bank and is easy to zero and easy to set for a specific weight.

Now, the keys to any good load. Good accurate ammunition needs to be consistent from cartridge to cartridge, which means overall length, case length, case capacity, charge weight, and bullet weights are all important. However, you don't have to be quite as fussy with Handgun loads as with Rifle loads because the operating pressure is lower for most handgun loads and you really can't expect to achieve sub 1/2 MOA with a handgun. BTW 1/2 MOA is basically 1/2 inch groups at 100 yards.

With handgun loads what is most critical is getting the powder charge correct and using a suitable powder. Case length only matters if you are loading up something on the "stiff" side like a 357 Magnum where the recoil may present the possibility of Bullet Pull. Even then, a variation in case length of as much as 0.007 inch really isn't a problem. Next most critical aspect is the assembled overall length, because this can effect the produced pressure of the assembled round. Smaller volume in the case at the start of ignition is sort of like a higher compression ratio in an engine. Except with a handgun you don't get knocking, what you can get is an overpressure load. While not normally dangerous a case that ruptures due to excess pressure can be quite scary for the shooter and in some cases cause minor burns or flesh wounds. So, with any load you put together you want to use the overall length listed in a specific recipe found in a load manual. Note, the maximum overall length for a particular caliber is almost NEVER featured in load data for semi auto calibers, so don't be alarmed by data where the OAL is shorter than the SAAMI maximum. However, when using non wadcutter bullets in revolver loads loading to the maximum OAL is rather typical. The reason for this is that overall length doesn't effect the feed cycle in a revolver but does greatly impact the feed cycle in a semi auto.

One example of this is the 9mm parabellum where you will find data that ranges between 0.06 and 0.010 inch below the SAAMI maximum for overall length. Most pistols today feed more reliably with a somewhat shorter overall length so most loads for the 9mm are developed using a shorter overall length. Because these loads were worked up using these shorter lengths they are perfectly safe to use because that is the test length that was used when that load was developed. However, do note that just taking a particular listed load and reducing that specific length by another 0.06 inch is NOT safe because that particular combination wasn't tested. Bottomline, use the listed data and don't go exploring on your own until you have years of reloading to guide you on going into unexplored territory.

scooter123's post is really good advice for you, the beginning reloader, Blued Steel. I want to add that since you are starting out with a 586, it looks like 38 Special/357 Magnum will probably be your first reloading project. As for trimming cases that grow over max allowable OAL, you won't see much growth at all in 38 Special or lower pressure 357 Mag cases. But if you load some hot 357, you will definitely run into case growth sooner or later. Since you are just starting your reloading activities, you won't have a bunch of brass with multiple loads on it so this won't be a problem for quite a while. So getting something to trim cases isn't a priority for a while.

Like scooter, I would also recommend getting a quality beam balance instead of buying a cheap digital. I use a RCBS 5-10 scale, which aren't made any more. But you can find them on eBay, as well as the 10-10 scales too. There are other quality scales on the market too. But don't skimp on your scale. Another reloading item I consider a "must have" is a powder trickler. It makes getting your final powder weight easier as it drops just a little powder at a time into the scale. And depending on your initial budget, you also need a powder measure or the Lee powder measure scoop set. That will speed getting powder into the cases by quite a bit.

And like everyone else, I also recommend at least 1 quality reloading manual. I personally have several including a couple of newer ones. The Hornady is a good manual to have and it has some very good info in the front of it for the beginning reloader to read through it. And yes, READ THROUGH IT! It can save you a lot of grief down the road from possible injury or ruining a gun. And it will give you a better understanding of the reloading process.

By the way, don't expect to save any money by reloading. Because what you will do is spend the same amount of money but end up shooting a lot more than when you were limited to factory ammo. Plus, you might find it to be a fun and enjoyable pastime like a lot of us just by the fact that you are building your own ammo instead of buying it. I find that reloading is an enjoyable pastime for me, especially when the weather is bad. It beats sitting in from of the stupid tube all day long doing nothing.

From reading your first post, I suggest you follow Scooter123's advice because you are a perfectionist.

Now if you want to reload safe, "accurate" revolver ammo, here are my suggestions:

1. Take all your fired cases and trim them 0.020" shorter than minimum case length. Do not deburr the case mouth because the sizer die knocks off the outside burr, when you bell the case mouth the inside burr is knocked off.

Your case now has a square edged mouth that will firmly crimp a bullet, the same length so you get a consistent crimp, and will never grow enough from resizing to need trimming again. The case will crack before it gets too long.

2. Seat your bullets to the crimp groove or cannelure for the best crimp. 38 Spl needs minimum crimp, 357 mag needs a heavy crimp.

Check your over all cartridge length to verify that it is not too long. Also check that the bullet nose does not stick past the mouth of the cylinder.

Your abilities to shoot a revolver accurately into a small group of bullet holes; sight alignment, trigger control, hand shaking, and flinching all have greater affect on group size; than the variations in your reloaded ammunition.

At the bottom of this thread is more information on reloading that answers your questions. Reloading ammunition is not an EXACT science. Close enough does work, variation does work, minimum to mid-range loads from any published manual is safe, there is seldom data agreement between different manuals.

The starting load data for a 150 grain lead semi-wadcutter bullet will work for 148 gr wadcutters to 160 grain round nose bullets as long as you are using lead or plated bullets regardless of manufacturer. The cartridge overall length will change, but you have SAFE ammo.

May you enjoy your new hobby .

EDIT: I find it difficult to believe that people reloading 357 mag, 41 mag, or 44 mag brass cases with near-max or max powder charges and NEVER trim the brass. I have pounded several brass cases, 357 mag or 44 mag, out of cylinders because the case mouth was stuck in the cylinder throat, case body stuck in the cylinder, and the primer was absolutely flattened flush to the case head. I removed the cylinder from the frame, inserted a wood dowel into the cylinder and stuck case, and pounded the end of the dowel to remove the case.

After the third event, I fired ALL of my 357 mag and 44 mag ammo, and trimmed every case as described above before reloading it. 38 Spl and 44 Spl brass can never grow long enough to be too long for the magnum cylinders. I'm sure M52 shooters trim their 38 Spl brass or at least carefully monitor case length.

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S&WHF 366

"So how anal is too anal?" I think you answered your own question.

I am in arjay's camp here. Keep it simple. Follow published load data and don't overthink it. I never have trimmed revolver cases, nor do I check their length. Just crimp into the cannelure or crimp groove. OAL yes, but not cases.

And you'll note that everybody recommend you get a couple of good reloading books and read the front part. Amen to that. My favorites are Speer and Lyman. Also Hornady and Sierra. Don't touch a press until you've read them. The online data only augments, not replaces, the manuals. Best are Alliant and Hodgdon/IMR/Winchester.

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USAF, 69-92
Vietnam, 72-73

As mentioned by several others, buy and READ the reloading manuals. Next, find a very experienced mentor to work with you.

I have shot competitively for over 30 years and have never trimmed any handgun brass, I seat to either magazine length or to the cannelure/crimping band. Have yet to have any problems with this.

I simply cannot hold well enough to see the difference between my bullet being seated 10 thousands of an inch one way or the other. Same with a 10th of a grain variation powder charge. None of mine are hot rod reloads, I find what shoots very accurately in THAT gun and then make lots of it.

I don't know ANY shooter that can see a difference between 4.0 grains of Unique verses 4.1....

Do as YOU see fit, I have better uses of MY time however.....

Randy

There is a huge difference in loading for benchrest rifle competition and loading .38 special for a revolver, just as there is a difference between quality and OCD.
If you are going to shoot handgun targets at normal pistol ranges, I'll bet lunch money you can spend an hour loading each cartridge and my mass produced IDPA .38 ammo from a Dillon will be indistinguishable in reliability and accuracy.

Knew a young engineer that was a total perfectionist, just out of school, knew it all. Spec'd all the parts she designed at 0.00001" tolerance even though they interfaced with parts that had 0.001" tolerance. Ran the machine costs and time way up, wouldn't listen to the boss, so she was finally fired.

If you load the middle of your data, crimp in the groove, your accuracy will be determined mostly by the quality of the bullet itself. Suggest you load some of these, then if you want play with all the other parameters of the load and see if they make any difference you can see on the target. Have fun.

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Science plus Art

Bold= I do
Underlined= I don't
These are the steps I've used for 30 years. Works just fine.

In reloading there has to be some basic rules to keep us all safe...................

One reason for the minimum and maximum case lengths.
Longer and shorter will work but, we need to start some where, right ?

Some bullets come with or without a cannelure for the use of a crimp on the bullet, called out in some loading data.
Do you need to crimp.. No.
Should you........... maybe.
Do I...............
on jacket HP and Lead high vel. loads, YES. Medium loads some times, target loads, some loads yes since they are more accurate but most do not receive a roll crimp.

I will put a light crimp on a lead bullet that has a "Can" but have been known to buy lead round nose designs that are "Clean", so I can adjust the OAL to any length my little pea picking heart wants.

Yes there is data and rules along with notes of what people have done to "Improve" the loads over the years but one must realize that minimum loads can get you in trouble just as easy as a full load or a load not designed for the age or condition of a weapon being used.

Have fun putting the puzzle together.

Totally agree!!
Once you have the manual/s read them atleast two or three times and then if you have questions - there are plenty of people here willing and able to help you out.

Case length has NO** effect on pressure SAFETY. Take two cases whose only variance is different lengths, seat two identical bullets to identical OALs . . . the INTERNAL VOLUME of the two cartridges is identical. The only thing that changes is the amount of case overlapping (bearing on) the bullet.

Let's take your example and see why it's not so vague after all:

For example:
38 spl case, 158gr Lead Bullet;
Start charge 4.1 Gr Unique.
Max charge 4.7 Gr Unique. Min OAL 1.440"

As long as your OAL is 1.440" or above (ie, this is the minimum INTERNAL VOLUME they tested), they are telling you THE COMPONENTS THEY USED were safe given the pressure of 4.7gr of THEIR BATCH of Unique.

As/if you drop the charge below 4.7gr, you could probably shorten the OAL . . . but that's up to you to test. If you used 4.1gr of Unique, you could probably use a shorter OAL, but certainly 1.440" will still be safe

Published loads like this are talking SAFETY and give you all the parameters you need to know . . . if you know how to use them. Accuracy, precision and suitability for purpose are up to you to determine.

** Varying case lengths can cause small variations in pressure, but these are not safety related. These changes are due to the amount of neck tension effectively exerted on the bullet. Precision rifle pays a great deal of attention to these differences to minimize pressure (ie velocity) variations and eliminate (eg) vertical spread over rifle distances.

Varying case lengths can cause other issues too . . . cartridge may not fit in handgun . . . lack of uniform crimps (neck tension again) . . . and in severe cases bullet setback (a significant reduction in OAL caused by (eg) recoil of the previous round). Due to short distances, handgun is normally only concerned about avoiding setback.

Very solid points everybody has brought up. Thanks for all the responses!

As much as I figure buying some reloading books is like paying for expensive pieces of the internet, I may have to invest. It seems as if most reloading books share a lot of universal information, such as the process of reloading and how to go about setting things up, what tools are necessary, what are optional, etc.

And

Pretty much sums up why I am hesitant on buying reloading books... Sure, a reloading book will get you in the ballpark, but I don't find it would help much in the advanced techniques of dialing in a round. A lot of basic "X caliber X bullet X powder" Searches will reveal someone posting the one line out of a reloading book that is pertinent - the starting load and specificity's.

Fair enough. A .020" case capacity difference is only worth about .07 grains.

What I gathered from that is, hand gun ammunition tolerances are pretty slack...

If you loaded 50 rounds out of your dillon, and I loaded 50 cases, spread over a .020" case length all crimped into the grooves, are you saying given the shooter doing his part all 100 rounds would be on a 10" gong at 25 yards? Or are you saying your 50 rounds vs. 50 anal retentive rounds are all going to be on point?

By just 'crimping in the groove', what if my load ends up being shorter than the 'min length' in that particular loading data publish? At what point is too short of a case and "just crimping into the groove" going to be problematic? The 1.135 mark?

Which leads me into....

If minimum length is 1.135 and I follow this approach to end up with a 1.115 length case, I can still safely load 4 grains of Unique into the case and seat the bullet as far down as needed for the crimp to be in the groove? Or how is it determined that I would be too far under min. OAL?

By knocking .040 thow off the max spec of 1.155, is that brass then limited to what it can be loaded for? I.e, mid-low target loads?

How important is it for the crimp to be in the groove? If it's not in the groove because the bullet would have to be seated too far in, how would the necessary amount of case to bullet overlap be determined?

True. I overlooked that. Would a crimp in a groove, and a crimp not in a groove produce a noticeable difference in neck tension?

Quoted from the LEE load data card:

Min. OAL: This is the shortest, safe OAL to be used with never exceed loads. Seating bullets deeper will cause higher, possibly dangerous pressures.

Having read that, I associated/interpreted that with if using less than a max load, I could just cram a bullet in the case to the crimp groove and the OAL is fine as long as it is not over max. BUT, at what point would it be a uh-oh scenario by starting off with a case too short?

Where as your interpretation makes more sense.... Use the Min. OAL as the benchmark, regardless of min or max charge, and determine what length case is necessary to put me in the groove, and go from there.

Yes... I tried to carry that same thinking into hand gun ammunition making... though as it seems, being that meticulous isn't as necessary in hand gun ammunition as it is for precision rifle ammunition.

As far as my current tooling goes, I bought the Lee single stage kit that comes with the powder measure, scale, bits and pieces... but I read that the scale was kind of finicky so I picked up a used good condition RCBS 5-0-5.... and I found a frankford digital scale on the cheap... so I have a few ways of measuring the powder. At least of them will verify the other

I figure if I really get into the high volume hand gun shooting and once I am a bit more experienced on what can just about be constants such as have a determined bullet and powder and have a consistent length batch of brass I will look into a Dillon.

Basically what I figure you guys are saying is, don't spend too much time making each round identical, rather don't have 50 brass 1.135 length, 120 this length, 85 that length and to just trim them all once so they're within a certain consistent crimp-able length, figure out a powder and bullet and start cranking out rounds.

I'm sure a lot of my questions now are really just experience related and once I actually get on the press I will see just how much variance and what not I can get away with here and there and still get consistent crimps...for now I'm just theorizing... time to put it into practice.

You have a lot of questions, many of which will be answered by reading 1-2 good reloading manuals.
You are already making some dangerous assumptions, like there is a linear relationship to oal & powder charge, just not true. Powders build pressures in a linear fashion until they start pushing into max & then pressures, depending on the powder can continue or spike vertically.
If you are using data under midrange, your oal isnt a huge factor. So yes, load to the crimp groove & go shoot. How anal do you need to be, enough to follow directions. Will it matter in your accuracy, only if you are able to shoot sub 1" groups at 25yds, if not, it isn't goung to matter much.

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NRA Cert. Inst. IDPA CSO

The better reloading manuals also have great 'how-to' sections besides just data where specifics for each type of case/cartridge are discussed. You need to study these thoroughly. I'd get the books and while you are learning and obtaining what you need, study. You can learn all of the aspects in a fairly short time, then concentrate on specifics for cartridges you will be loading. For things like OAL, you will learn that.....


Old revolver cartridges based on cases that used black powder aren't as sensitive to OAL because the required volume inside for black powder is not as critical for smokeless powder.

By the same whim, most semi auto cartridges were designed for higher pressures and with smokeless powders in mind. These cartridges are very sensitive to AOL and require a caliper to verify depth of seating.

The OAL of bottleneck rifle cartridges are most dependent on what fits in a particular rifle chamber. Depth of bullet seating isn't as important as 'headspace' which places the cartridge in the chamber and how well a bullet fits without excess space that can blow out.

Bottleneck rifle cases also have an 'expander' which opens the mouth of a resized case to accept the bullet by neck tension.

This just scratches the surface. Get the books and start boning up. Then you will know about what you will need and why.

There are a lot of threads here about needed equipment to reload and sites for vendors like 'Midway' have pages dedicated to starting reloading and what is needed.

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"He was kinda funny lookin'"

You HAVE to be anal to do things safely. There is no choice about this. Be anal or risk getting hurt.

The other kind of anal is a choice. People polish their cases, separate them for consistency, trim each case, weigh each powder load. But if you aren't looking for minute of angle accuracy, you can do just enough to get what you need to do what you want....

I can be meticulous with ammo that I want to be consistent and take more time per round in preparation OR if I just want to practice a lot of defensive shooting at the indoor range at 5-10 yards, I can put a lot of ammo together in a short time by not being so picky about sorting and cleaning brass.

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"He was kinda funny lookin'"

with my revolver ammunition, the case mouth usually cracks, and is discarded before i ever have to trim it, lolol

Most handguns, bullets, and shooters can't shoot whatever difference may exist between precision pistol rounds (ie, done using many of the steps one would take for precision rifle) and typical handgun rounds. ~4" sight radii, hand-held, low BC bullets, short distances, etc.

Straight-wall pistol brass never needs shoulders bumped back, so they never grow and "never" need trimming at all. Some may actually shrink over several reloads. (I say "never" because my experience is with 380Auto, 9mm, and 45ACP . . . but somewhere else there may be exceptions.)

After thousands of rounds reloaded using the same cases, I've never measured or trimmed pistol brass and never encountered an issue related to a faulty crimp. However, I *do* separate seating from crimping and I *do* use a Lee FCD for the crimp, and that die works well with variable length brass . . . though it may pose issues by also resizing some lead bullets.

So I'd echo suggestions by others to read** some background material on reloading not provided by (eg) some guy named "Twoboxer", but by organizations with reputations known and on the line. That will provide safety, move you up the learning curve, and give you a basis to deviate from. Hornady and Sierra books have good reloading technique sections. Many recommend Lyman, but I have found it of no value vs my needs . . . YMMV.

Then by all means experiment. Only by testing will you learn whether the application of some precision rifle techniques are of value in YOUR handgun shooting.

** ETA: Wanted to add . . . you're a smart guy with at least some relevant background and experience. Yet you missed the *implications* of the data being presented in load recipes. There are many more such implications. (EG, load data doesn't determine the OAL, your pistol does.) You will save yourself a lot of time and lots of use of a kinetic bullet puller by allowing reading rather than reloading to help you see those implications.

Rimmed cases, like 38sp & magnums do stretch w/ full power loads & at some point may need trimming to keep the roll crimps consistent but load at midrange, you re likely to lose the case to a mouth crack before it needs trimming.

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NRA Cert. Inst. IDPA CSO

First and formost I am going to assume that You have a press, scale, powder measure, and case trimmer. From Your post it sounds like You have the Lee die set that You use with a hammer. I hope this is not the case. If You have all the above tools, then pay attention to all of the replys and You won't go wrong. I praise You for asking questions before starting.

I also follow the reloading catalogs regarding OAL and particular bullets. I'm very low volume, and don't trim my std velocity loadings.

What I'm saying is the first derivative (slope) of pressure is quite flat near the middle of medium powder loads in ordinary (non-magnum) pistol cartridges, and small changes in all the things that go into pressure differences do not change the resultant pressure curve enough for you to see the changes on the target at ordinary pistol distances, say 50 yds.
The inverse square of total bullet dispersion is equal to the sum of the inverse squares of the individual components contributing to the total dispersion.
Or if you're not into math, another way to say is that a shooter who is capable of 5" grouping at 50 yards with a S&W 6" 686 (gun capable of 2") is never going to know whether his ammo is capable of 1", 2", 3", or possibly even 4" because the gun is in his hands, not a ransom rest. Even with a Ransom rest, most test show that a S&W revolver with even mediocre ammo is better than the average shooter.

My best bullseye ammo through my 8" Model 14, from a rest, will shoot 1" possibles at 25 yd all day long. My IDPA ammo will keep them in the 10, ring from rest or 2".
Like I said, I bet lunch money you can't shoot the two type of ammo through your gun, handheld, at 25 yards and tell me which is which by the size of YOUR groups.
In engineer class, we had a saying about pointless precision: "Don't measure it with a micrometer if you're going to cut it with an ax."
The person holding the gun is analogous to the ax.

I had a loading student who wanted to weigh ALL his .45 ACP loads because he KNEW he would shoot better. So we loaded some Unique .45 loads by the book, middle of the data. Then a batch .3 grain over, and another batch .3 under.
We shot the three separately, then mixed together 5 of each and shot them all together at 20 yards. I gave him a pencil and asked him to mark which shots were which on the final target: he couldn't because it was all one group.

This is called sensitivity analysis in engineering terms: if you change a variable and the resultant changes little, then the system is NOT sensitive to that parameter. Expansion ratio (which is what changes with changes in seating depth) matters little when you are in the flat part of the pressure curve.
At maximum pressure, the slope of the curve is steeper, and it matters more. Just like if you're standing 10 feet from a cliff, another foot closer matters little, but if you're only a foot away, another foot closer matters a lot.

YOUR .020" CHANGE IN .38 CASE LENGTH IN A 6" REVOLVER MIGHT PRODUCE AT MOST 0.2" DIFFERENCE IN POI AT 25 YDS, WHICH YOU WILL NEVER SEE.

Internal ballistics is a horribly messy set of mathematics including 2nd order differentials. That's why we all benefit from the basic theory part of loading manuals (without all the math) and using tested loading tables. As long as you stay off the edges of the data, you can be off some without any danger or significant changes in the results, especially in ordinary pistol loads.

Welcome to the fun hobby of reloading.

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Science plus Art

From post #15 by BluedSteel:

"Pretty much sums up why I am hesitant on buying reloading books... Sure, a reloading book will get you in the ballpark, but I don't find it would help much in the advanced techniques of dialing in a round. A lot of basic "X caliber X bullet X powder" Searches will reveal someone posting the one line out of a reloading book that is pertinent - the starting load and specificity's"

You've got to walk before you can run. Forget about "advanced" techniques until you've mastered the basics. It just might be that the people writing the load manuals know a bit more than you who have yet to produce a single round.

I still refer to my books even though I've been reloading since 1988 and have probably 100k rounds under my belt. And some of the guys giving you advice above have a lot more experience than mine. Listen to them. Get the books and read them.

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USAF, 69-92
Vietnam, 72-73

WOW!

OKCFO5, I had no idea that you had that much knowledge of mathematics and ballistics practical application. Very impressive young man!!

Randy

Well assuming you can hit a 10" plate at 25yds every time, yes, the accuracy diff will be minimal. Like 2" instead of maybe 3" on the fat side. Look at 0.020" on you calipers, it isn't much, a thick sheet of paper.
As far as buying reloading manuals, you can NEVER have enough vetted reference points. The internet has changed things up but figuring out good info from bad requires knowledge, that can be obtained on the net but you have to know this from that. Good forums are helpful, but don't think buying a couple good manuals is a waste of $$. You may need info when you have no internet access???????? Besides, how can you even consider yourself anal about this unless you have like 6 reloading manuals??

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NRA Cert. Inst. IDPA CSO

Again with the solid points. Highly informative. More than answered my initial question(s).

It seems as it is difficult and unlikely to produce ammo so varied that a free hand shooter will be able to tell the difference.

I sense some sarcasm, but if not... what die set is that?

Very convincing... I'll be buying a book tomorrow or in the very near future.

This fully answers just about any question I might of had regarding case pressure and how seating depth might affect it when considering a sub-maximum load. Very nicely put.

You specifically say ordinary, non magnum pistol cartridges... So the theory of having a flat pressure curve at a medium load in a magnum cartridge doesn't apply? Why not?

My understanding is in rifle rounds pressure signs are obvious where as pistol cartridges not so much obvious. When experimenting with a hotter charge and approaching higher pressures, without blowing a gun up or losing a hand, how much is too much pressure, or too dangerous of a pressure determined? (with the average joes ability to determine that, not with facility type tooling)

What you are saying is intriguing. My level of physics doesn't go into the realm of ballistics... but what you're saying is making sense on a theoretical level.

Are they linear in this sense: For example, take a peak(ing) pressure level produced by a 4.7 Gr charge at 1.440 OAL. Could the same pressure level be reached by a 4.0 Gr charge if the OAL was shortened?

And then once that pressure is reached, it is no longer a linear increase in pressure but the relation changes to a relation of powder charge increase = OAL decrease?

Increasing powder charge raises pressures. Shortening oal in pistol loads, raises pressures. It's just not linear for all powders in all calibers. Small volume, high pressure rds, like 9, 40 & 357sig, oal plays a more significant role than in say 357mag, especially as powders get on the faster side of the burn rate chart. With slower powders, oal has almost no affect on pressures in larger cases.

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NRA Cert. Inst. IDPA CSO

Most reloading books are made by bullet makers for their brand. But not all. Lyman 49th has generic info for jacketed bullets, the lead bullets are more specific.

I use the Speer books a lot which specifies exactly what components are used. That doesn't mean that you can't use other components, but that you drop back on the powder charge and work the load back up again. Ever since the shortages hit I've had to be more creative in putting together components from various manufacturers.

If a bullet is similar materials (lead, jacketed, whatever) and similar weight and profile with about the same length of straight side along with the same diameter, you can pretty much substitute if you drop the load back and work back up.

Using this guideline, being careful and using common sense, I haven't had any problems in almost 40 years of reloading.

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"He was kinda funny lookin'"

If you want good ammo, you need to be sure your brass is all the same length. Everyone seems all cranked up about trim it, don't trim it, check it, don't check it, blah, blah, blah.

Check it and trim if needed. Check it often enough that you know it's about the same length. Beyond that, it's not even a conversation worth having if you want to make good ammo. If you don't check it, you don't know. You wouldn't spitball any other part of reloading ammo. Case length is no different.

You want a consistent crimp, you need a consistent length.

Buy a manual and read all the reloading instructions. Do not rely on the internet.

If you are not getting into competition events or reloading for a rifle, the Dipper that came with your Lee Dies will work ok with no danger of overcharge. just follow the instructions that came with your die set. It's really quite simple. Get a Lee case trimmer for the .38 Special if you want but really not necessary. Just follow a few safefty rules and enjoy. There are a few great powders suitable for the .38, 9MM, and .380ACP.. Have fun ,as you get more into reloading you can make a few changes. It is addictive . I enjoy reloading almost as much as shooting. Well not as much and as someone just said, you may not save a lot of money but you'll have a lot more fun. Don't worry about the crimp groove on the bullet, most of the bullets I load don't even have one. You may want to try some lead bullets in the .38. I just bought 2000 147 grain lead bullets . Again ask a friend, read a good manual. get on some good blogs.A lot of good information and experience on this blog.. ( Don't smoke, watch TV or talk a lot while loading. Just you and and your press). Enjoy.

Generally speaking, any recipe in a manual has been created and tested with given bullet seated to the crimp line or cannelure, it's as simple as that. But you still must measure to be sure because there can be a big difference in OAL between just barely to the crimp line and almost over the crimp line.

But basically what i'm saying is that if you are below the crimp line or you are too deep to not see the crimp line at all, than you are seriously out of spec and need to figure out what the deal is.

Spend some time over here!

http://smith-wessonforum.com/138256790-post1.html

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Really? U saw it in Wikipedia?

I re-read the OP. You sound detail oriented. Case length is a detail. The difference between good ammo and ammo that's "good enough" is attention to details. Reloading as opposed to hand loading.

Posted by Blued Steel in post #28:

"My understanding is in rifle rounds pressure signs are obvious where as pistol cartridges not so much obvious. When experimenting with a hotter charge and approaching higher pressures, without blowing a gun up or losing a hand, how much is too much pressure, or too dangerous of a pressure determined? (with the average joes ability to determine that, not with facility type tooling)"

The only way the average joe can determine he is within safe pressure limits for handguns is to stay within the limits of loads published in recognized reloading manuals. The ballisticians who develop that data have the education, training, experience and the equipment, including strain gauges and/or piezoelectric transducers. This all comes under the rubric of internal ballistics. And you can't determine whether or when you are getting into a dangerous pressure zone without all that equipment and knowledge. There is no linear relationship you can count on when you start pushing the limits of published data.

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USAF, 69-92
Vietnam, 72-73

Well yes & no. If you or the gun isnt capable, the minutia isnt going to matter. If your accuracy criteria is a 10" plate @ 25yds, case length or brand isnt going to matter much. My mixed brass 45acp Will break 2" @ 25yds, offhand, sorting cases & trimming them to exact length isnt likely to improve that much.

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NRA Cert. Inst. IDPA CSO

This why we use vetted data from manuals or powder companies sites. An exp reloader can develope loads w/o data, using a chrono & watching pressure signs, like case head expansion & marking, extraction & primer flattening. Though most visible pressure signs show up when you are well over pressure.

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NRA Cert. Inst. IDPA CSO

"Though most visible pressure signs show up when you are well over pressure."

That's my point.

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USAF, 69-92
Vietnam, 72-73

And your point exactly is???
Reading pressure signs is sort of a voodoo thing. Why we stick to book data. I load for several wildcat rds, no data, so you go slow, read the chrono data & try to extrapolate where you ate going based on presence or absence of any excessive pressure signs like sticky extraction, case head marks, case head expansion.

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NRA Cert. Inst. IDPA CSO

Yes. In theory. We know that reducing OAL increases pressure just like increasing powder charge increases pressure. And, we know that the more OAL is reduced, the more the pressure goes up. What we don't have is a scale or chart that accurately describes this phenomenon. Nothing that says that an X decrease in OAL produces exactly Y increase in pressure. We also know that there is a kind of tipping point where the change in pressure due to change in OAL happens quickly and unpredictably. Again, we don't have an accurate way to gauge when that will happen.
In theory, you could create the condition that you wrote of, but there is no way to know if it is actually doable, or what OAL would get you there. The only way to see it is to do it and measure it while it happens. IMHO, not a good idea to try to answer this question.

I'm agreeing with your point that, absent published data, you're likely into an overpressure regime before you see the signs. You can extrapolate if you like, but the risk is on you. Calculated risk for the seasoned expert. Foolhardy for the novice al la the OP. I think we're in agreement here.

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USAF, 69-92
Vietnam, 72-73

...get the manuals and read them. They are the most complete instruction there is. If there is some fine point that you don't understand from the manuals, find a specific video for the problem you are having, or ask here.

People are often confused by headspace, C.O.A.L., crimping and a few other details that are important details. If you can get it fine, if not, ask.

PS You have permission to use your press and equipment, but not to make completed ammo for shooting. Test the steps and assemble some dummy rounds and maybe a few live ones for chambering, but take them apart until you are sure you know what you are doing. An impact bullet puller is an essential thing to have.

I have to admit the when I popped off my first reloaded rounds, I turned my face away before pulling the trigger. After I found out that I didn't have any catastrophic errors, I got more confident.

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"He was kinda funny lookin'"

After reading through this thread, I'm going to sit the bench and observe for a while. Wow....

Update: I've shot few boxes of hand loads and my hands and gun are still intact

I took the advice and got my hands on some books and played around with some powder-less loading's testing out the dies and crimps and how much variance affects the crimping procedure. Even with a 1.135" case and a 158 gr SWC loaded to the groove, I still have about .015" to go before I reach min OAL.

I cranked out 50 meticulously loaded 4.0gr Unique +/- .001" case length/crimped 158gr SWC 38 specials, which all shot great. During that I determined my Lee powder measure has a fairly consistent powder throw, +/- .1gr, and loaded up some rounds only weighing the first round, every 10th, and last round of a powder measure thrown charge and ended up with some +/- .1 gr loads w/ a case length of +/- .0025". Which all shot as great as the first box I loaded. Certainly nothing I could differentiate as far as differences go with my off-hand shooting. They mostly made a 1-ragged hole in paper at 10 yards with the odd flier that was probably shooter-induced.

Considering the gun is a .357 Mag I loaded up a couple cylinders of 4.5 and 5.0 gr Unique loads - which according to the books is creeping into +P territory. I have yet to shoot those.

Definitely happy with the 586 and my loads. I think a bug might have bitten me though... I want more revolvers and want to try out several other loads