military cases vs. .223 questions...

skyugo · #1 12-27-07, 22:27

i'm aware of the crimp. from what i understand the 5.56 is thicker brass than the .223 resulting in a slight decrease in internal volume. i'm not making "hot" loads by any means. i'm loading them to about 2900 fps (2.8 grains of IMR3031) with a 55 grain fmjbt bullet. am i going to run into internal pressure issues with the mil. cases vs. commercial?

basically going for a large volume of reasonably priced plinking ammo.

how much POI difference will i be likely to see with an equal powder charge in a .223 case and a 5.56 case? i'm far from an MOA marksman at the moment. basically i want to ding 6" plates at 100 yards. not a hard task right?
obviously as i progress i'll want to create some more accurate loads, and for that i want all the same cases.

i'm basically just asking if this is safe and reasonable...

jmart · #2 12-27-07, 22:49

LC cases run as light as commercial .223 cases.

Most .223 cases run from 91 to 94 grains per case.

I've seen some that are heavier (PMP IIRC), but I don't see those too often. Basically, if it's a LC, a Win or a Remington I treat them as interchangeable.

You also can run across Federal stamped brass. It weighs comparable to other commercial brass, but often it runs softer. If you load these hot the pockets will give out after one or two laodings. I segregate these and download them a grain or a bit more and they'll last another loading or two.

.308's may be different, but this is my experience w/.223.

skyugo · #3 12-27-07, 22:59

LC? will that be stamped on the case head

i've got a lot of what i assume to be mil cases marked "W C C 84"

ooh some LC's...

MAL

FNM

PS

a lot of the mil stuff is crimped still, some has been reloaded apparently as the crimp is gone. so i'll probably just load that up.

i'm wondering if that WCC is commercial.

PALADIN-hgwt · #4 12-27-07, 23:00

xxxxx

markm · #5 12-28-07, 10:19

Quote:

Originally Posted by skyugo

from what i understand the 5.56 is thicker brass than the .223 resulting in a slight decrease in internal volume.

Internut myth scientifically proven wrong by a water volume test, if I remember correctly, by a good guy on TOS. In fact, I think the findings were the opposite. (specifically with 223/5.56) Mil brass had a higher internal volume. I think the decreased internal volume myth comes from 7.62 mill brass, which may actually have a lower internal volume... don't hold me to that, however.

Quote:

am i going to run into internal pressure issues with the mil. cases vs. commercial?

basically going for a large volume of reasonably priced plinking ammo.

how much POI difference will i be likely to see with an equal powder charge in a .223 case and a 5.56 case?

You won't have ANY issues with your loads. I've been mixing mil and commercial brass for ever without any problems at all. My most common load is 3100 fps out of a 20 inch barrel... hotter than commercial .223, yet milder than 5.56 military ammo. I've never had so much as a popped primer.

skyugo · #6 12-28-07, 16:59

Quote:

Originally Posted by demigod

Internut myth scientifically proven wrong by a water volume test, if I remember correctly, by a good guy on TOS. In fact, I think the findings were the opposite. (specifically with 223/5.56) Mil brass had a higher internal volume. I think the decreased internal volume myth comes from 7.62 mill brass, which may actually have a lower internal volume... don't hold me to that, however.

You won't have ANY issues with your loads. I've been mixing mil and commercial brass for ever without any problems at all. My most common load is 3100 fps out of a 20 inch barrel... hotter than commercial .223, yet milder than 5.56 military ammo. I've never had so much as a popped primer.

any chance my weak-ass little loads won't run the gas system on a middy 16" carbine?

thanks for the info though guys, very reassuring. my upper will be here on jan. 2.

i've been an AK guy up til now. i really need something accurate in my arsenal though.

skyugo · #7 12-28-07, 17:06

Quote:

Originally Posted by PALADIN-hgwt

The Sierra 3rd Ed. shows 24.8 IMR-3031 is a maximum load under a 55 grain bullet.
In the Sierra 5th Ed, "AR-15" section they list 24.6 IMR-3031 under 55 grain bullets as a maximum load yielding 3000 fps from a 20 inch barrel.

I realize the 2.8 load you mention is a typo, but I earnestly hope you are NOT trying 28!

FWIW I would suggest using H335 around 24.5 to 25.0 for your 55 grain fmj plinking load. H335 measures very well, unlike stick powders which tend to hang up and yield inconsistent dropped charges. HTH.

Paladin

oh shoot. i meant 22.8

i've been using a lee charge meter. i tested a few charges before i just jumped in with it. it seems to meter alright. i suppose i won't be getting match results. my next purchase will definitely be some ball powder.

markm · #8 12-28-07, 20:16

Quote:

Originally Posted by skyugo

any chance my weak-ass little loads won't run the gas system on a middy 16" carbine?

Shouldn't be a problem. When I first started reloading I had some very weak loads during the build up process and they all cycled my weapon.

I've seen MANY more cycling problems with import ammo loaded HOT with the WRONG powder.

skyugo · #9 12-29-07, 01:38

Quote:

Originally Posted by demigod

I've seen MANY more cycling problems with import ammo loaded HOT with the WRONG powder.

well i've got some guatemalan surplus too so i should get the full experience.

markm · #10 12-29-07, 17:08

Quote:

Originally Posted by skyugo

well i've got some guatemalan surplus too so i should get the full experience.

I've not heard bad things about GUAT. I think GotM4 said it flashes like a camera. But I never read any complaints about its performance. Radway, Early PRIV M193 under the Wolf Name, and Igman come to mind as some of the piss poor propellant leaders.

skyugo · #11 12-29-07, 19:36

Quote:

Originally Posted by demigod

I've not heard bad things about GUAT. I think GotM4 said it flashes like a camera. But I never read any complaints about its performance. Radway, Early PRIV M193 under the Wolf Name, and Igman come to mind as some of the piss poor propellant leaders.

ah well that's good to hear. I actually enjoy a good muzzle flash...

with the price of .223 what it is lately i think most of what i shoot will be loaded by me.

thanks for all the help btw on my various threads.

Rmplstlskn · #12 12-30-07, 01:48

Besides the GUAT M193, which I love to shoot, as it leaves my XM193 for classes, I also picked up 2k of the brand new, virgin GUAT brass from Wideners earlier in the year (gone now...)

Besides the smaller flash hole, GUAT brass is nice...

Rmpl

toddackerman · #13 12-30-07, 14:32

Quote:

Originally Posted by demigod

You won't have ANY issues with your loads. I've been mixing mil and commercial brass for ever without any problems at all. My most common load is 3100 fps out of a 20 inch barrel... hotter than commercial .223, yet milder than 5.56 military ammo. I've never had so much as a popped primer.

I concur. I've found it to be a real PITA to keep your brass sorted so that it doesn't have a little of this and a little of that.

This being said, my plinking ammo is mostly Military cases, and a few commercial cases (5%) mixed in. I load to the "Mid Velocity Level" (Check the manuals) for any type of Powder for my 55 gn. FMJBT w/c bullets with very good results. There is no reason to load "Hot"! All it does is wear out your Upper and Barrel Throat sooner. As long as the weapon functions with the BCG and Springs that are in it for SHTF...I think you're GTG.

You won't notice a difference in POI on 6" plates at 100 yds. with mixed cases. Until you're trying to put 5 shots through one hole like the Bench Rest Shooters, the gun and ammo will shoot better than you will from an unsupported position.