I have a problem that I could use some help with.

When I am working up a load, when seating the first bullet, I adjust the seating die a bit at a time until I get the right depth/COL.
Then, the very next bullet seats a few 1/1000'ths too deep.

This has happened to me with different calibers, both rifle and pistol loads.

Right now, I am working up some .44 Magnum loads.
As per my loading manual, I set the COL to 1.60". The second bullet I seated went to 1.5970. This has happened multiple times.

I find myself backing the adjustment out on the die and slowly working to the correct seating depth on each round, which seems like a waste of time.

My question is, am I doing something wrong, or does this "just happen"? Is .003" enough to worry about, or am I being too finicky?

Measuring the difference:


Close-up of the cannelures.
The deeper one on the right:

Don't sweat it. You are wasting your time trying to get perfectly identical COLs. Measure a box of factory ammo and it will vary also. Bullets and cases are not all perfectly uniform. The only ones who might need to be concerned are ultra match shooters or snipers.

You realize 0.003" is less than a sheet of paper in thickness. It means nothing. The bullet nose profile probably varies that much. If your variation gets to 0.010", then start looking for something wrong in your gear or technique.

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NRA Cert. Inst. IDPA CSO

You are being WAY too picky, With the case volume of the 44 Magnum you could probably have +/- 1/16 inch of variation without causing any excessive spikes in pressure, especially if you are loading below the maximum charge.

Question_even if you are using carbide dies, are you using case lube? Using case lube like Hornady One Shot will help with more consistent COAL. Try ten cases with lube and ten without and measure them.

Agree with others-if you can equal the variance in a box of factory ammo, you are doing well.

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The American dream is alive

The brass casing might be a tad to long/short, or the bullet itself may be off, don't sweat it, your in range....

If you are using a progressive press, the upward pressure of the sizing, flaring, and crimping stations will change your seating depth a tad. Usually it will increase my COAL by as much as .005". When you are making your seating die adjustments, generally you are working on one cartridge at a time and the other stations are empty. So you get a little upward pressure on the toolhead in the press. When the other stations are assembling cartridges the seating depth will change with that toolhead play, but usually it goes in a very predictable direction. Usually it increases COAL, but depending on what machine design you are using it could decrease it. Either way, it is a fairly predictable change.

I forgot to mention, I am using a single stage press and I seat and crimp in two different steps.

It sounds like I'm doing ok?

Several months ago I measured a box of Federal premium, 45 acp and found no deviation in oal. This was the only time I have measured factory ammo so I have no idea of consistency. But I assumed it would be quite good.

I strive for .003 and settle for no less than .005 but I do not to claim to be an expert on the matter.

Sounds about right.I think what you're running into is that the stem doesn't really fit the nose and hits on the ogive of the bullet and those tend to vary.Id say your rounds are good enough.

IME, I get a slightly different result when seating in small increments, than when seating all in one stroke. I've seen this with many different types of bullets. The seating in one stroke almost always results in a slightly shorter OAL. When I'm doing the small increments, I stop when I think it's just a tad longer than what I want. So, when I do the one stroke seating, it seats exactly where I want it. Like others wrote, a couple-few thousandths is no big deal.

I just went through this with 9MM, and I got the same response. Factory ammo also varies. I checked all the factory ammo I had and none of it was exact.

I set my COL to just hit the cannelure on revolver rounds and don't even measure. For the 9MM when COL is important for proper chambering, I settled on about 10% longer than minimum COL and the rounds chambered, fired, and extracted fine.

Case length would have little to do with OAL, but it would look diff at the cannelure. Really, actually look at say 0.005" on your calipers, it's nothing. In tests over the chrono, I've not seen any appreciable vel increase, all things being equal, pressure = vel, until I get to 0.150" & that is in the tiny 9mm case with a med burner like Unique. When you get to 0.030", things start getting interesting but still nothing to worry about. At 0.060", vel increase is very noticeable, so 0.050" is where I start getting concerned, as in bullet setback.

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NRA Cert. Inst. IDPA CSO

You're having the same reaction many AWAKE AND AWARE new reloaders have. But don't worry, your results are to be expected, and are fine.

A quality single stage press might be able to hold OAL variation to +/-0.0005" . . . IF all bullets had exactly the same shape and profile. Since bullets are not identical and they are not (necessarily) pushed down from the very tip, they will be contacted by the bullet seater at slightly different points. That leads to different OALs, and it is especially true with hollow points like the ones you are using.

[For future reference, progressive presses have more ways to produce differing OALs lol.]

As someone already mentioned, case lengths could be different but that would have no effect on OAL; however, the end of case might fall at a different point vs the cannelure.

Those rounds you made look fine

You are doing a good job, attending to details. This is a case of "close enough" , not "all exactly the same". Carry on.

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S&WHF 366

since you have some calipers .. measure a hair on your head.
That'll give you some perspective on what your dealing with.

Your right to ask when you have doubts .. but your doubts are within the thickness of a human hair.
not bad at all once you measure the runout of a box of factory loads.

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it just needs more voltage

Thanks to everybody for your time and input.
It's nice to hear that I was worrying about not much.

I guess the perfectionist in me might have to come to terms with the limitations of the tools and components.

Thanks again.

Au Contraire!!!

You OBVIOUSLY are a danger to yourself and all around. Pack up all your powder, primers, bullets, cases, and equipment. I'll PM you the address for shipping. You'll thank me some day.

Really, you will!

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Really? U saw it in Wikipedia?

The little differences will have no bearing on your shooting. Once you get to rifle loading, and are competing in Benchrest, they you may need to pay this close of attention.

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H Richard
SWCA1967 SWHF244

I have been reloading for quite some time now (around 36 years) and have a plethora of all different brands and ages of cases in the calibers I shoot. There are slight variations in the cases and brass does stretch as it gets shot more & more. I no longer separate different brands or segregate cases by how many times they have been reloaded.

In a Revolver like your .44 Mag. unless you are many thousandths off, the few thousandths that make up the variation mean nothing. In an Auto Loader where tolerances are more critical (head spaces on face of brass cartridge) there are also slight variations that won't mean a lot to most shooters. I have seen some really tight guns (Ed Browns for instance) that are VERY finicky about reloaded cartridge tolerances, but for instance in my Colt .45 acp's - they never even have a hic-cup when I reload my mixed bag of .45 acp cases.

If you can keep your variation to + or - a couple of thousandths you are doing fine!

In my case almost every col will vary its a revolver there is a pretty big range if its not sticking out the front of the cylinder its not too long, of course stick to the do not exceed col info I checked a new round (40 s&w) and the col was not even close to the recommended max COL, and the and the length varied from one to another

Been reloading since I was a teenager.... A stickler for perfect reloads due to years of target and benchrest shooting - the OAL was always a pain UNTIL I started setting my dies off the ogive of the bullet and stopped worrying about measured OAL due to the slight imperfections associated with bullets.

Not even then.

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NRA Cert. Inst. IDPA CSO

Do yourself a favor and stop measuring OAL! For automatics and rifles it has validity, but not for revolvers. If you are using cannelured bullets simply seat to approximately the center of the cannelure and forget about it!

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Gunsmithing since 1961

If you really want to see some wonky COL's, load up some pulled down jacketed soft point slugs. That'll teach not to bother pulling out your calipers

Your ammo is fine the tolerance is in specs your feel with calipers could be off that much. I check the first 3 the resume reloading. once the dies are locked down tight your good to go.

You're over-thinking and over worrying—it just isn't that important. If you can hold the COL variation to +/- 0.003", you are doing well.
As far as your picture goes, as long as the case mouth in within the crimp groove, you are a good as gold—crimp and be done.
1) Bullets vary that much. Measure your bullets.
2) The base of the case can vary—manufacturing tolerances, ejection, bouncing on the ground, etc. Measure a case all around (and not across the whole case, but just the edge of the rim to case mouth) and see how the case length can vary.
3) EVERY press has some flex. Flex will cause a variation.

Personally, I think you are brave in admitting that you lack self control and patience. You don't want the frustration of reloading equipment without every possible component available, to upset your piece of mind. And I can tell you that having reloading equipment and supplies in your home but unloaded will leave you batty! Then the problem of your children coming to visit and stay for reloading and dinner, that will destroy the whole idea of kicking them out in the first place. Buddys would want to spend time with you, and even worse go shooting with you. One other problem is that in the future the prices will go up, and you won't b able to load for 4 cents a round like I did in the early 80's. Who cares how much you save not buying commercial ammo. You will have all the frustration of not doing reloading for the prices of 30 years ago. My hat is off to you for saving all the frustration that would otherwise be coming your way. Ivan

PS One problem I am facing now is all my brass is full and I have ample powder, primers and bullets for thousands of reloads. But the weather is so bad I can't make anymore empties and I'm out of storage space for more reloads. Yes it is a total life of frustration you are avoiding!

A family member came to me to ask about reloading equipment choices. Knowing the family member's personality and get 'er done as quick as possible general attitude, I said "you are not cut out for reloading...don't do it." He was mad at me.

This thread is refreshing. Unlike my family member, you have the proper attitude and disposition to be a great reloader, Hillbilly77.
We should always worry about the quality and consistency of our loads. These concerns will keep you safe and make your loads accurate. However...minor COAL variance to that degree is beyond your control.

I'd say you're OK. It's hard for a "perfectionist" new reloader not to overthink some aspects of reloading. My OCD drove me nuts at times. I once got on a roll and weighed about 250 bullets and separated them into three piles. OK for a bench rest shooter, but I was working with cast bullets in my .44 magnum revolver . Some minor differences jes don' matter...

Yeah, what they said. I would shoot them. They look fine.

Do you not have a crimp on your standard die set? You have a different die for crimp? Just curious, since I can find no difference in handgun loading when using a standard die seating and crimper in the same die in one step, instead of a seperate crimper. Just an an extra step that I can find little value in doing. Some rifle loads will perform better with a seperate crimp die, but handgun loads are very forgiving. I measure COL in terms of fractions of inches and not thousands of an inch.

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Gary
SWCA 2515

The pictures appear to show uncrimped rounds. I find that the crimp process changes the OAL slightly, so that will drive you crazy too

Just put the word "about" in front of your target OAL. Since your seating die does not put pressure right on the very end of the bullet, but rather part way down the shoulder, variations in bullet geometry will cause some differences in your OAL.

Mike

Just to add to my comments:
>As per my loading manual, I set the COL to 1.60"

What makes you think that is the COL for your gun? That is simply the COL used for testing. For most testing, the lab uses a shorter than normal COL so pressures will go up faster than the average reloader will find in their gun. So, you can consider that to be the minimum COL the data applies to for the EXACT bullet they used.
COL depends on several factors, most of which the test lab has no knowledge of:
1) the EXACT ogive of the bullet being used (and don't think the ogive doesn't change--bullet manufacturer's seem to like to change their bullet geometry/design and not notify any one).
2) The cartridge length that fits in your magazine and when the magazine lips release the round to be fed. If the COL is too lip with respect to when the magazine released the round, the round tends to "jump up" and jam at the top of the barrel and if too long will simply smash into the feed ramp.
3) the feed ramp geometry.
4) the chamber and lede/rifling of the barrel.
In general, the "best" COL is the longest that feeds and chambers 100%.

From Ramshot Powders:
SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as
1) magazine length (space),
2) freebore-lead dimensions of the barrel,
3) ogive or profile of the projectile and
4) position of cannelure or crimp groove.

• Always begin loading at the minimum "Start Load".
• Increase in 2% increments towards the Maximum Load.
• Watch for signs of excessive pressure.
• Never exceed the Maximum Load.

Hey been reloading since 1975 and I still overthink things at times. As stated - center of cannelure will do it. Wait till you do your first necked rifle cartridge. PITA to NOT Over Think everything.

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Thanks,
Steve

I already did some last fall.
I ended up pulling several bullets that did the same thing to me.
I'm probably a lot pickier than I need to be.
But, I started reloading primarily to get consistent, repeatable results and accuracy. I got sick of inconsistent factory ammo.

With my deer rifle, I'm not happy to hit a paper plate at 100 yards. I want nickel or quarter-sized groups at 200 yards.
My loads aren't quite there yet, but I was getting 3-4" groups at 200 - plenty accurate for a deer rifle, but I know it can do better.

I have noticed this exact phenomenon myself...

I have been reloading for about 2 years now, and am just as picky as Hillbilly with just about every aspect of my reloading. This thread has been a good read for me and the advice given to Hillbilly has been just as helpful to me.

One theory I have about this, yay or nay: We both use a Hornady Lock N Load press. The bushings are O-ringed as most of you know. I was thinking that this little oddity might be attributed to the O-ring under the Lock N Load bushing giving that little bit of slack??? Was thinking of getting a second press, (RCBS) to try seating with and see if this still occurs... But after reading this, I think I'll pass on the whole experiment.

At the risk of being a nerd, it is something that "just happened." I have the same thing happen when I am setting up for a different OAL.

This quote from the hyper physics website explains what happens when you gradually adjust that OAL on the first bullet and then the next one comes out a little short:

"...the amount of force required to move an object starting from rest is usually greater than the force required to keep it moving at constant velocity once it is started."

Simplified, when you seat that second bullet you are making one stroke all the way and it is moving into the case much more easily that the one that you seated in increments so it goes a hair further into the case because there is less friction.

It's an interesting physical phenomenon. I bet if you accelerated or slowed your pull as you seat the projectile your OAL would lengthen or shorten accordingly.

This stuff gets me all fired up:P. Fascinates me. Great website that I use often:

Force

And no that amount of variance is not bad. Well within safe limits. Props for paying attention to details buddy

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Trucks and guns.

I'm glad I found this thread. Being new to reloading and wanting to make sure I do everything right, I too noticed a variation in COL when I was loading some .40 S&W the other day. I feel better knowing that small variations in COL is normal.

I'm guessing by now you realize you are doing well and you are making good ammo. If all the variation I got was .001" I would be very happy! Totally normal and totally safe. Stop worrying and go shoot your ammo...

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Freedom is never free!!
SWCA #3437

I enjoyed reading about this "problem". First, let me echo the compliments paid to you about your exacting measurements. Yes, you needn't be concerned about safety or accuracy, but who knows when your meticulous practices might save you? I too am a little fussy about COL, but for different reasons. I switch loads, powders, bullets, etc. a lot. I also seat and crimp in two steps to minimize bullet nose distortion. Seating stems never seem to fit bullet ogives all that well. If you incrementally seat a bullet while checking COL, the multiple trips into the ill-fitting I.D. of the seating stem will often leave a ring on the ogive as it deforms the bullet. More trips, more deformation. The effect is especially pronounced with pure lead bullets. Your photographs show a very faint ring on the bullet ogives. Very telling. In a perfect world the I.D. of the seating stem would be contour ground to exactly match the bullet nose shape. It never does. The manufacturers sell round nose and SWC stems, but they just don't contact the bullet perfectly for all the varieties out there. Check the inside of any seating stem that's seated a few hundred bullets. Full of gunk. How does the gunk stay in there? It lives in the gap between imperfect stem and bullet. It usually takes me four or five trips into the seating die to get the seating stem set, and these multiple squeezes do more bullet deformation than one push.

The effect is small, too small to affect any reasonable pistol round, but like you, I do sweat it a bit for high intensity rifle rounds.

This forum is fun. The theory above about bullet momentum during seating is entertaining reading. But far be it from me to discount theories or solutions. This hobby has a couple of hundred years of trial and error behind it, and there are still things to be discovered.