223 case failure

[Neurosis 0]

I had seen a pic of a similar case failure, either here or on another forum... don't remember. But I was at the range today, and while cleaning up my brass I saw what looked liked a pistol brass that maybe someone in a neighboring booth had ejected towards my direction. Upon closer inspection, it was the bottom half of one of my 223 casing and saw the top half on the ground. I was shootn RemUMC, Hornady 40gr, Wolf Match, and Ultramax Match, don't remember which brand this case was from as I shot pretty much everything. Now, I know that the brass will get dented, but this is different.

 

[kresk 10,063]

My guess--improper charge (load too hot), less likely firing pin too long (crater edge on the primer.)

[BullShark012 1]

Hmmm, that's pretty strange. I've never seen anything like that & I can't imagine how that could even happen. It looks like such a clean spearation, like it was cut with a saw. There is a dent on the lower section at the cut, Is there a coresponding half of that dent on the top piece?

 

I suppose you never noticed any unusual sounds since you didn't refer to any of that. The round manufacturing stamp appears to be Lake City 2005. I have a bunch of that it's Once Reloaded Military Brass I got from Ammunition to Go. Lake City Once Fired Miliatry Brass

 

I haven't really fired very much of it yet, but it seems great to me so far. I hope your experience is not indicative of a problem with it.

[Old Salt 0]

If only time it's ever happened to you it's probably not a head space problem but I would have it checked. If excessive HS they will seperate but usually closer to the base. Cratering is a sign of excessive pressure as the post above noted.

[MD_Willington 11]

I have a pile of that LC brass from HSM, the shoulders tend to crack on them... but the stamps are from the 70's.. old stuff

[TonyRumore 1,332]

You had excessive headspace with that round.

 

Tony

[Neurosis 0]

Thanks for the reply guys. It must have been an excessive charge from a RemUMC, never had that issue before or with any other brass. I've got a net brass catcher, so I see about 80% of everything that gets ejected.

[banshee 69]

I'm with Tony, excessive headspace

[6500rpm 670]

Can someone add some information to support what signs to look for that indicate excessive headspace vs what traits indicate excessive pressure?

[TonyRumore 1,332]

You will separate a case with excessive headspace even if the load is not real hot. The case expands, the body grips the chamber walls tightly, then the back part of the case slides backwards until it hits the bolt. If that slide distance is long enough, it will break the case in half. It is usually the rear most portion of the case (close to the head) since that area is not supported by the case walls. But sometimes, like in this case, the forward part hung fast, and the rear half slid back. If you're real lucky, the whole case slides back, the shoulder gets blown forward, and you get away with it. The more taper your case has, the more lucky you will become. That's why you don't see many case head separations with tapered rounds like the 7.62x39.

 

Excessive pressure is much harder to measure/see. You might have excessive pressure and the case looks fine. However, if your primer is excessively flattened out, the primer pierced, primer flow back through the bolt face, etc.....you probably have excessive pressure, but again, maybe not. There are other issues that might show these traits and not be due to excessive pressure.....but generally speaking, if you your primer is all fucked up, you usually have excessive pressure.

 

If you look at his pic (the primer) you will see the raised ring around the firing pin strike. That is where the primer flowed back into the bolt face. Most likely caused by the firing pin hole in the bolt, being too larger for the pin itself. I don't see excessive pressure, since there is still a very good radius on the primer where it meets the walls of the primer pocket.

 

So....in my opinion, the firing pin hole in his bolt is too large, and head space was excessive with this round. Pressure looks fine.

 

Tony

[banshee 69]

Edited August 3, 2008 by Banshee

[BlackDog 1]

this one is probably excessive headspace.

This was a reload I made. I make mild reloads straight from the IMR book, always at least 2 grains less than the max listed. I use 99% of my ammo for plinking, so I don't need any hot rods.

the brass that I save from firing in my saiga seems to have a stretched shoulder by a few thousands more.

I have boned up reloads that won't even come close to chambering in my Mini14, but these same reloads will drop right into the Saiga chamber no problem.

I have probably resized at least 3000 pieces of brass with one 223 die and some of the thicker walled brass presses really hard. I have since retired it.

I have shot probably 500 rounds thru my Saiga and have had one of these seperations.

Edited August 4, 2008 by BlackDog