Help with military 5.56x45mm brass

[Brass Fetcher]

I have been experimenting with loads for my 5.56mm AR-15, using '04 Winchester military cases and 55gr bullets.. so far, the Winchester Small Rifle primers seem to crater at 22.0gr of IMR4895 and the primers seem to want to push out of the pocket with 21.0gr of IMR4895. Personally, I like my primers slightly round and seated as deeply before firing as after! Does anyone have some loads/suggestions? Thank you.

 

[ocabj]

22.0gr of IMR 4895 is pretty mild for 5.56NATO loads. Assuming you are seating the bullets to the proper depth and it is truly 4895, I'd try a different primer. I've heard Winchester small rifle primers have piercing issues. I have had Winchester primers pop out of hot .223/5.56 loads in a Wylde chamber.

Try CCI standard, BR4, or #41 primers.

 

[P-32]

Like ocabj already said your load is pretty mild. I found Remington 7 1/2's to be a great primer for 223 and they shoot to about the same POA as CCI's bench rest primers. Winchester and Federals' just don't seem to be up to the task.

 

[DaveInFloweryBranchGA]

I agree with the other fellas. Use CCI or Remingtons. I used CCI when I shot highpower with an AR-15 and had zero problems.

Regards,

Dave

 

[Brass Fetcher]

Thanks everybody. I will try stepping up the load a little and then new primers.

JE223

 

[KHawk]

Just got back from the range and saw your post. I'm having the same problem with Win Small Rifle primers in a .223 Rem load for a benchrest 700 VSL. I'm loading H335 at 23.3 gr under a Hornady 53 gr flat based HP. Primers cratered on 99% of the rounds that were shot today.

 

[RecoilRob]

Are you guys sure that the 'cratered' primers are, in fact, a sign of overpressure or just a bit of primer flow into the oversize FP hole?

If you could post a pic or two it would help with the figuring out.

The more important thing to watch for is the outer radius of the primer flattening out. So long as some radius is still there, you probably are just fine pressure wise. The loads listed that are causing concern seem WAY mild to be having pressure problems to me.

 

[KHawk]

RecoilRob, in my case you could be right because it is not an extreme crater. The primer is not as flat as some that I have seen in the past, But the same load with Federal primers does not crater at all.

Ken

 

[taliv]

Thanks everybody. I will try stepping up the load a little and then new primers.

woah! if you're seeing pressure signs, "stepping upthe load a little" isn't the first thing you want to do.

1. make sure your gun works with factory ammo ok
2. make sure your necks aren't too long and your bullet is seated to proper depth
3. get yourself a chronograph and verify
4. swap primers/powder/cases/etc

 

[3006mv]

military brass is thicker so have a smaller case capacity, dowload by 10%

 

[TooTaxed]

My favorite .223 load uses 25-gr #4895 behind a .55-gr bullet and Winchester primers, and I have no problem with pierced primers. Suggest you check your firing pin tip...

 

[TooTaxed]

Another thought...have you checked your case length? Too long cases result in higher pressure, and I find I need to trim and de-burr many cases...

 

[Khornet]

Agree with tootaxed.

That's the load I use, or sometimes even 25.4 gr. I've used Win. Fed. Rem. CCI primers with no problems. Bet that either a) there really is no problem or B) it's something else: case length, primer material, firing pin/hole etc.

AFAIK, GI brass and civilian are really interchangeable except in 7.62 NATO/.308.

 

[snuffy]

junk science

Reading primers, for pressure indicators, is junk science. Meaning so many other things can influence how primers appear after firing that their appearance is missleading. Cratering usually shows a too large firing pin hole, it doesn't take much pressure to crater. A FP held against the primer by a heavy spring will not back out of the FP hole in the bolt to allow the crater to form. IF there's a lot of clearance around the FP hole in the bolt face, the cratering flows around the FP into the clearance.

I've used thousands of WW SR primers in my .223 AR loads for my bushy. I never noticed any issues with any of them concerning high pressure. But then I rarely "read" pressure by primer apperance. I "read" pressure by velocity from by my pact chrony. IF the loads are doing what is considered normal for a 20" BBL, I know the pressure is whithin limits. If I was pushing the upper limits, I would measure Case Head Expansion. CHE can give an indication of excessive pressure.

 

[normbal]

woah! if you're seeing pressure signs, "stepping upthe load a little" isn't the first thing you want to do.

1. make sure your gun works with factory ammo ok
2. make sure your necks aren't too long and your bullet is seated to proper depth
3. get yourself a chronograph and verify
4. swap primers/powder/cases/etc

Taliv has some good points.

FIRST THING I WOULD CHECK is CASE length. Try trimming to MINIMUM length. THEN at the same time, make sure your bullet OAL isn't pushing the bullet into the rifling. It isn't likely, but I don't know if you're loading for a bolt action only, or AR15.


Try MILITARY primers. CCI makes these, I use them for loading .308 for my military guns. The harder brass keeps the round from going off when the bolt slams home on the round and the firing pin keeps going until stopped by the primer cup. The harder primers also stay in the primer pocket better as mil spec ammo is MUCH hotter (higher pressure) than commercial.

Get a vernier caliper. Mike the firing pin. Mike the ID of the firing pin hole. If you can't get your caliper in, use a sharpie to mark up the firing pin and insert it into the bolt face and twist slightly; this will make a small mark on the firing pin you can then get an OD on. You'll probably find there is a few thousandths difference with prevents binding but also allows some primer flow.

I use a chrony and flattening of the primer to guesstimate pressures then back off the hot load by a grain (sometimes more) and chrony again. then tweak the load. I trust this method as I've done it for decades, and have a lot of support for it from high-power shooters who've been collectively handloading longer than I've been on the planet. Proof loads pressure are a HELL of a lot higher than standard loads, and while it's not wise to go much over SAAMI standards, you're not likely to if you stay within published loads.

Keep in mind ALL the load books are conservative loads; there's just too damned much liability in recommending loads that just MIGHT blow up someone's gun if their scale, loading technique, OAL or other factors come into play.

Have fun. Let us know how it turns out.

-Norm