So what is .04" to a 9mm load ?

[Nevada Ed]

I know there are a lot of short OAL and long OAL for all types of
bullets being made and used for the 9mm pistol.

We have seen what Hornady and Hodgdon have to say as well
as Speer, Lyman and Sierra, plus all the other manuals and
internet data that is out there.

I am finally done with all of my testing except for one test with
a SD JHP that is shorter than what the company recommends
but I just have to see if it will feed 100% since the fac spec OAL
did have some failures to eject with two slow powders.

You can go less and you can go more in the OAL of the loads
in my picture but these are what worked for me in a C9 pistol.
The "Micro" picture helps me see what little difference there is
in my short and long OAL for the bullets used.

I have found that OAL can have added fps, lower fps, along with
good or bad accuracy. I almost have all the pieces of the puzzle
that I am working on, put together for just the C9 I have been
testing over the past year.

Here is a picture of my loads.............
(and I do use factory ammo for my SD use)
lost pic..hang in there.

 

[Forrest r]

Don't know if this will help or not, ramshot put this out in their reloading manual.



Nevada Ed, this is in no way shape or form directed at you. You're good at what you do. I'm just putting it out there for people to read and decide if it has any meaning to them.

I've always said that reloading is putting components together for the worst case scenario's.
Meaning if your target oal (example only) is 1.00 and your equipment can only load bullet within .007" of your target oal then your bullets are anywhere from .993" to 1.007" oal.
If your target weight is 6gr (example only) and your powder throw average is accurate to .1gr and 1 out of every 20 throws are .2gr difference then your target weight then your reloads are .2gr within your target weight.
If your using mixed brass then they will have different wall thicknesses & internal dimensions. Your reloads are only as good/rated for your thickest walled cases or cases with the smallest internal volume.

What does all that mean???
That you can load 1000 rounds of ammo and up to 5% of them could be problematic. In actuality the percentage is much less, hence a .2+ increase might be loaded in an extremely thick walled case and have the bullet be seated .007" less. All of the extremes, but it can and will happen. That happening in itself while not idea, doesn't get most reloader in trouble. It's when these things happen when lowering the recommended oal or are loading +P+ loads/max loads.

It isn't allot but if the reloader loads to a lesser oal and it adds a 1000psi to the load. And the difference in the seating die & powder throw and another 1000psi to the load. Then using a extra thick case that has an extremely small internal capacity also add another 1000psi to the reload. Bad things can happen.

Just something to think about, that safe reload using zip powder went for 28,000psi to 33,000psi in a hurry (only .008" difference in oal). Couple that with an odd throw of powder and thicker than normal cases.

 

[gwpercle]

Your particular gun will determine the OAL it likes. The measurement in the book is more or less a starting point.
As long as you are not loading at maximum, or compressing a powder charge in the case , a few .000" either way is not going to hurt.
If it is not a max load, feeds, fires and ejects reliably in my gun, then a few .000"'s either side of the books stated OAL is not going to bother me.
When I started in 1967 this information was not even given, you had to work out your on seating depth based on factory loaded ammunition and good old try and see what works.
The way I see it , the claim is if it isn't EXACTLY what is listed your gun will explode. I don't agree with this and it seems some obsess over it.
Gary

 

[fredj338]

I ran some tests with 9mm & WST & unique. Same cases, bullets & powder, just changing oal. The loads were not Max & that matters quite a lot. My findings were oal changes don't really show much affect on vel/pressures. In all the liars, shortening oal raised vel, all things being equal, vel=pressure.
Vel changes were linear & pretty small searing in 0.010" increments. At 0.050" deeper, both powders showed quite an increase in Vel, almost 100fps. At a max load I would expect an even larger vel increase.
So in factory loaded self def ammo, I watch oal of rds chambered multiple times. If the shorten up 0.050", they are put aside. I never sweat oal shorter than 0.040".

 

[Rule3]

Heck with some lead bullets in my CZ 75 Custom I have load them so short I am not gonna print it here.

The MBC 124 Round nose is so fat it will not plunk at any "normal" COL. Just reduce the charge a bit. But also can consider that listed data is regular pressure so there is some wiggle room to +P values.

Pointed FMJ bullets will chamber at "normal" COL

 

[JBnTx]

The MBC 124 Round nose is so fat it will not plunk at any "normal" COL.

I switched to their 125gr 9mm Cone bullet because of that.
The LCN type bullet works better and I get even better accuracy than the round nose bullet

 

[Nevada Ed]

That lead bullet reminded me of a bullet that I loaded for my old WW2 Radom, many years ago.

It was a little 100 grain Hornady JRN with lead exposed at the base... but it did have a fat Ogive and I kept a few since it was odd.

Here is a picture of it next to a 115 gr plated Berry............
I do not think that they would "Plunk" the same ? !

 

[Forrest r]

Heck with some lead bullets in my CZ 75 Custom I have load them so short I am not gonna print it here.

The MBC 124 Round nose is so fat it will not plunk at any "normal" COL. Just reduce the charge a bit. But also can consider that listed data is regular pressure so there is some wiggle room to +P values.

Pointed FMJ bullets will chamber at "normal" COL

+1

Done the same thing with some extra long home swaged bullets & cast hb bullet (extra long 150gr hb's). No data to be found so it's start slow & low with a slow burning powder that has allot of play between min & max.

Not trying to preach doom & gloom by any means. It's just 9mm's & 40s&w's seem to have their fair share of problems. Fast burning powders with .2gr to .4gr difference between min & max loads don't leave allot of "wiggle" room all by themselves. Add 40/1000th's+ difference in the oal/seating depth of a bullet. It can get ugly real quick.

Keep in mind that the ramshot chart I posted above is using a rather slow burning power, zip. On hodgdon's burn rate chart it has:

25. aa#2
26. ramshot zip
27. imr 7625
28. hp-38
29. ww231

Compared to:
ramshot competition/7.
bullseye/13.
titegroup/14.
clays/10.

https://www.hodgdon.com/PDF/Burn Rates - 2014-2015.pdf

The 9mm is a wonderful caliber, I've owned/shot the 9mm for decades. When I bought a contender bbl in 9mm, it was a real eye opener. Just started playing around testing/loading for accuracy.

Good luck and enjoy your 9mm's

 

[scooter123]

First, I feel I should point out that Ramshot ZIP is is a fairly "fast" powder and very likely to be much more sensitive to changes in overall length than a slower burning powder. So, that example provided by Ramshot was chosen to illustrate an example that could be labeled as being at the extreme end of hte spectrum.

However, it does point out that reloading can present unanticipated variables. Such as variation in thrown charges. I do a 50 piece Capability Study on any powder that is new to me so I have a good grasp on how consistently it meters in my powder measure. I use this to determine what powders need to have each charge hand weighed. BTW, statistically a 0.2 grain variation in just 20 throws is a likely indicator that in 200 throws the variation will exceed 1/2 grain. That is the value of Statistics, it can reveal the variation that will occur at the extremes.

As for case weight differences having a significant effect on the actual measured volume, brass is a distinctly dense material. So, a difference of as much as 1/2 grain in the weight of a case will require lab grade measuring implements in order to measure the change in the enclosed volume. It's more likely that a 0.0003 inch difference in the sizing die may produce a larger variation in the enclosed volume than 1/2 grain of brass will. Note to self, check into the actually density of brass and determine how much volume 1/2 grain of brass actually occupies.

Point is that we all are taught to Start Low and Work Up. Which is normally a very safe approach. However, if you start low with only 5 rounds of ammunition you really don't have a sample set large enough to take into account Statistical Variations and their effects. Personally, I don't make a decision to increase my charge weight until I've done a full workup on both Accuracy and Function using a sample size that allows me to actually observe the effect of unanticipated variables.

 

[Forrest r]

First, I feel I should point out that Ramshot ZIP is is a fairly "fast" powder and very likely to be much more sensitive to changes in overall length than a slower burning powder. So, that example provided by Ramshot was chosen to illustrate an example that could be labeled as being at the extreme end of hte spectrum.

However, it does point out that reloading can present unanticipated variables. Such as variation in thrown charges. I do a 50 piece Capability Study on any powder that is new to me so I have a good grasp on how consistently it meters in my powder measure. I use this to determine what powders need to have each charge hand weighed. BTW, statistically a 0.2 grain variation in just 20 throws is a likely indicator that in 200 throws the variation will exceed 1/2 grain. That is the value of Statistics, it can reveal the variation that will occur at the extremes.

As for case weight differences having a significant effect on the actual measured volume, brass is a distinctly dense material. So, a difference of as much as 1/2 grain in the weight of a case will require lab grade measuring implements in order to measure the change in the enclosed volume. It's more likely that a 0.0003 inch difference in the sizing die may produce a larger variation in the enclosed volume than 1/2 grain of brass will. Note to self, check into the actually density of brass and determine how much volume 1/2 grain of brass actually occupies.

Point is that we all are taught to Start Low and Work Up. Which is normally a very safe approach. However, if you start low with only 5 rounds of ammunition you really don't have a sample set large enough to take into account Statistical Variations and their effects. Personally, I don't make a decision to increase my charge weight until I've done a full workup on both Accuracy and Function using a sample size that allows me to actually observe the effect of unanticipated variables.

Yes and no, Zip is in the same league as hp-38/ww231/trailboss. Is zip faster than bluedot/unique/herco/powerpistol??? Yes, but it's allot slower than bullseye, clays, reddot and ramshot's competition.

"BTW, statistically a 0.2 grain variation in just 20 throws is a likely indicator that in 200 throws the variation will exceed 1/2 grain."

Again, yes and no. To someone who does stats then that's correct.
To someone who reloads they just got a powder charge .2gr over their intended/target weight. The big question is how many time does it happen in those 200 throws???

There's a difference in military case thickness and commercial case thickness. And then there's differences in the thickness of the commercial cases. Remington being the worst offender. Then there's a huge difference in the web thickness of different case mfg's. Let along the mfg's redesigning of the cases, hence different fonts on the head stamps.

The reloader ends up with cases that have internal differences/volumes like this. Both cases weighed the same but for some odd reason 1 mfg used more brass to support the web of the case which in turn made less volume in that case. Case weights have nothing to do with internal volume of that case, it's the shape that counts.



All's I'm saying is these things add up. Anyway the op asked if 40/1000th's of an inch difference in the seating depth of a bullet made any difference. I simply provided what a powder mfg tested/printed.

Everyone looks at things differently, I look at a .2gr overcharge as just that, .2gr over the intended charge weight. U look at it as over 100's of throws it ='s out to nothing. You look at case weight as the determining factor of all case volumes being =. I look at how they're shaped/constructed.

To each their own.

 

[m657]

"Heck with some lead bullets in my CZ 75 Custom I have load them so short I am not gonna print it here."

This is currently at issue with family member who bought PPX in 9mm.

It really likes factory 115 Blazers, less so 124 FMJ. The trigger is pleasing, but OAL at 1.169 doesn't chamber reliably in it for either 124 or 147 cast lead. Same load is very well liked by a couple Sig 9mms.

As bit a PITA as this bottom feeder deal is, maybe I really should stick with revolvers.....

 

[fredj338]

"Heck with some lead bullets in my CZ 75 Custom I have load them so short I am not gonna print it here."

This is currently at issue with family member who bought PPX in 9mm.

It really likes factory 115 Blazers, less so 124 FMJ. The trigger is pleasing, but OAL at 1.169 doesn't chamber reliably in it for either 124 or 147 cast lead. Same load is very well liked by a couple Sig 9mms.

As bit a PITA as this bottom feeder deal is, maybe I really should stick with revolvers.....

Why I keep preaching oal is gun & bullet specific. Btw, 1.169" is SAAMI Max. SAAMI Max rarely ever works in any caliber.

 

[Nevada Ed]

With a maximum OAL of 1.169" with the 9mm case...........

I always wondered if a little 115gr Ball or plated would work out
at that long case length, for accuracy if it worked in a pistol.

Just that the thought of a bullet only being seated the depth of just two dimes............
makes me shutter if the minimum pressure on the bullet would cause it to jump the case on chambering...........
and then have the trigger pulled !!

I chicken out and go with 1.14" OAL.

 

[fredj338]

With a maximum OAL of 1.169" with the 9mm case...........

I always wondered if a little 115gr Ball or plated would work out
at that long case length, for accuracy if it worked in a pistol.

Just that the thought of a bullet only being seated the depth of just two dimes............
makes me shutter if the minimum pressure on the bullet would cause it to jump the case on chambering...........
and then have the trigger pulled !!

I chicken out and go with 1.14" OAL.

Or just as bad, dislodge during feeding. I like a very min of 1/8" inside the case neck on handguns, about the case neck on a 357sig, & one full caliber in rifle.

 

[m657]

Gents: due to discussions like this, I am reconsidering the application of various data that once seemed so 'easy' to understand.

In reality I'm an old revolver guy that was quite satisfied with the performance gleaned from lessons in that realm over the decades.

Enter the bottom feeders: somehow the lurid attraction of various features has suckered me into the shoals of such nonsense as 'case mouth head space' and 'OAL and the phase of the moon' etc.

I appreciate the comments of all who take the time to clarify what works better and why.

...although part of me continues to consider 'smokeless powder' a mere passing fad....

 

[rwsmith]

In the simplest terms...

There is room to make minor adjustments if a cartridge won't chamber right, or they vary a little in bullet seating or something of the sort. If you change more than a few 1000ths shorter or are at max load it's a good idea to drop back the charge a few tenths of a grain.

I don't have pressure testing equipment so that's the way I work it. It sounds vague but this is the way I work it. Don't do max load unless your components match the book closely and even then back off and work up. The way a load 'feels' is subjective, especially in a semi auto, but I've 'felt' some hot published loads and didn't like them so I backed off.

Last but not least. The most accurate loads are not usually the hottest. There's no need to push the top if you are after accuracy. If you are shooting at something living, that's a different ball of wax. There you are welcome to push to the max within reason if you care to.

 

[m657]

Agree on accuracy IMHO is not achieved with max loads....usually about 75% level or so seems to work for me.

Now I'm reworking my set up to install AutoComp and 147 cast FPL and I see Hodgdon has only one load for it...and in a FMJ no less.
Their site shows .355" /1.1000" OAL/3.6~4.0 for 827~916fps.

I expect to start with the lower (for FMJ) being about the upper (for lead). Or is it that direct?

Where else can I find AutoComp recipes besides handloader?

 

[BC38]

Well, as illustrated in this graph it would seem that the answer would be an increase in pressure - but then we all already knew that. For Ramshot Zip powder that increase would seem to be around 4000psi - or roughly 17%.
For other powders the pressure increase may be more or it may be less. But there is no question that in such a small casing there WILL be a pressure increase. In some cases, maybe an unacceptably high pressure increase.