Cratered Primers

[ColoradoShooter77]

This is the first time its happened to me on a .223 load, been loading this caliber for years.

I did 25.6 grains H-4895, 55 grain Nosler bullet, Rem case, CCI 400 primer. They were seated to 2.230". The max charge on the 55 grain bullet is 26 grains in my Lee 2nd Edition book.

The cratering is pretty mild, but its there. I'm going to back this down to 25 grains and I should be ok.

I'm glad I was shooting an AR-15 with a 5.56 chamber.

 

[gamestalker]

Those really don't look too bad. But then again, reading primers is sort of like reading tea leaves, it's highly questionable. Some primers are softer / harder than others, so appearance can be deceiving.

I know my primers and my weapons, so for me, it usually provides some level of insight. But if I were to use a different primer from what I commonly use, I wouldn't be at all inclined to rely on primer flow. Bolt lift in a bolt gun, brass extraction distance in an AL, where I'm at on the charge table, and chrony results when combined, are much more reliable for estimating where I am with pressures.

GS

 

[Walkalong]

Look perfectly fine to me. No flow into the firing pin hole, edges nice and round.

 

[PJSprog]

Agreed, those don't look bad at all. Your primers didn't completely flatten out and expand, and those aren't really "craters" as I define it. They are a bit flat, though. Probably wouldn't hurt to back off a bit. Looks like the Hodgdon site shows 25.0 - 26.0 for a 55gr bullet as well. You may just have a batch of thinner cups.

 

[buck460XVR]

Look perfectly fine to me. No flow into the firing pin hole, edges nice and round.

I agree.

 

[Rule3]

Double ditto

 

[ColoradoShooter77]

Ok, cool guys! Its nice to have some expert input here! I'm still going to back down to 25 grains and see how that goes. The recoil on these were a little stouter, its definitely a hot load.

Also, the Nosler Varmageddon's are longer than the 55 grain FMJ's, by a good bit. That could be part of the issue as well. My Lee book doesn't differentiate with bullet type....its just "55 grain jacketed bullet".

 

[W.E.G.]

If you are running 5.56 pressures, I recommend that you discontinue use of the thin-cup CCI 400 primers, and move up to the thicker CCI 450.

I had all manner of problems with the 400's back in the 90's.
Switched to 450's, and the problem went away immediately.

 

[ColoradoShooter77]

Ok, good point. I'll pick up a box at the next gun show.

 

[JimKirk]

Nosler Data gives 25.5 gr IMR4895 as a maximum load for Six of their 55 gr bullets ...

http://www.nosler.com/nosler-load-data/223-remington/

Those primers look fine to me no cratering in that photo...

 

[carbine85]

I agree with the above. Those primers are okay. Use mag primers.

 

[ColoradoShooter77]

I put together a new load tonight....24.8 grains IMR-8208, CCI 450 primer, Rem case. I seated these out to 2.250, should lower the pressure a tad. This is 1/2 grain below listed max for a 55 grain bullet.

 

[W.E.G.]

 

[ColoradoShooter77]

So does that look like a good load to you? If I'm reading that right, I'm only at 46,000 psi with 24.5 grains.....I could easily go another 1/2 grain or more?

That's some cool stuff by the way, the quickload!

 

[Average Joe]

They look fine to me !

 

[peels]

Primer looks OK, but the extractor mark on the 2 cases that are in focus may be an indication that pressure is on the higher end.

 

[spitballer]

They have a recognizable sheen kinda looks like a gold record around the primer which I've always associated with higher pressure. Nevertheless I wish my case heads looked that clean, my rem 700 leaves a rimmed crater. Also agree with w.e.g. mag primers might be worth using

 

[W.E.G.]

 

[W.E.G.]

Be very conscious of the H2O volume of your cases.

Most 5.56/.223 cases tend to hold about 30.0 grains H2O.

A very small variation in H2O capacity makes a major change in pressure calculations under Quickload.
For instance:

 

[W.E.G.]

Whether you get a crater on your primers has as much to do with the machining of the boltface as it does with pressure.

For instance, the "upgraded" DPMS "GII" in .308 caliber has produced many, many, negative reports for "cratered" primers since its release. Completely a boltface issue - not at all an ammo issue.

Yes.
Use MAGNUM primers in your warm 5.56 loads.
The extra 0.005" primer thickness makes all the difference in the world.

Work up to any of the loads I posted above.
Everybody's rifle is similar.
Everybody's rifle is different.

Hot weather DOES make a difference, even if the manufacturer tells you their powder is "EXTREME" - as in supposedly not affected by high temperatures. Simply untrue.

I tested it by comparing velocities of ammo at ambient summer temp, and ammo that I let cook on my shooting mat to about 130 degrees. I got about 100 fps difference in velocities. To get that much difference in velocity, you need several thousand PSI more pressure. Every case, and every primer, holds together quite well... until they don't.

That extra 100 FPS that you can "push" most guns is NOT worth it.

 

[ColoradoShooter77]

I'm going to test the 24.8 grain 8208 load this weekend, that's probably where I'll stay with it. I'm not interested in testing my luck here, lol.

 

[Rule3]

But magnum primers give you supposedly more spark so that will change your "warm" loads. Use what the powder makers or manuals say to use.

Nosler states a Rem bench rest, Hodgdon a regular Win SR primer

Change the primer change all the results.


Of course there are always 41 primers, what did we do without them?

Quickload is a useful "tool" but it is math algorithms and not the same as a true measure of pressure or velocity.

 

[ColoradoShooter77]

Supposedly the Wolf magnum primers are just a harder cup, same burn rate.

I've been loading for a mini-14 for years without issue, but the AR is a little different. Its a learning curve. The load that I posted in my original post was definitely hot, but still out of the danger zone.

I'm just going to stay about 4% off the max load with a proper seating depth on the bullet and I should be good to go.

With the 16" barrel on my AR, the starting or mid-range loads would be pretty slow.

 

[Rule3]

I use the regular Wolf small rifle, I bought them years ago, they are harder than Win or CCI

 

[W.E.G.]

I've shot identical powder charges using "standard" and magnum primers respectively.

I have no way to measure the pressures, but according to the chronograph, the velocity was completely unaffected by standard vs. magnum primer. I've read in the gun rags and manuals the admonitions about the supposed effect of magnum primers and pressures. Quite remarkably, not one bit of it documented by so much as a shred of actual evidence.

Its been quite a few years since we did the test, so you will forgive me if I can't recall the exact loads. I know we were using N540, and N135, and IMR 4895, and Winchester 748 in fairly hot 5.56 loads.

If you read the Quickload manual, the author talks about how magnum primers may cause higher or lower velocities, or simply have no effect at all. I find it telling that Quickload makes no distinction in predicted velocities or pressures on the basis of choice of magnum vs. standard primers.



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