Stuck case

[Smithjdsr]

Shot my Bushy, and my buddy shot his yesterday. Bad news. He got a case WAY stuck in the chamber (an AR- I don’t know whose barrel, just that it’s 20”). It sounded normal (LOUD) but didn’t eject and couldn’t be cycled with the charging handle. He took it home and got it out with a brass ram rod- he said it was REALLY stuck.

He was trying a hotter load, but below “max” from the LilGun chart. He’s also US Army vet and I assume when he claims that the chamber and bore were “clean” he knows what that means and how to do it, so I ruled out a carboned-up chamber- it was about his fourth or fifth shot.

Is a stuck case a sign of over pressure? (Sorry, I don’t have the case for a pic, but he says it doesn’t look bulged or misformed and measures ‘normal.’)

[Bmt85]

So it’s an AR, that jammed after the round was fired, and wouldn’t cycle. Did he try mortaring it before using a rod?

What was the exact load?

Was it new brass?

What is the case head growth of the case that jammed it?

What is the brass length after sizing?

Did that brass show any signs of pressure (primers, ejector or extractor marks)?

I have a feeling it is case length grew too much and jammed it, but need more info.

[Hoot]

So it’s an AR, that jammed after the round was fired, and wouldn’t cycle. Did he try mortaring it before using a rod?

What was the exact load?

Was it new brass?

What is the case head growth of the case that jammed it?

What is the brass length after sizing?

Did that brass show any signs of pressure (primers, ejector or extractor marks)?

I have a feeling it is case length grew too much and jammed it, but need more info.

When reloading used cases, especially if they have a history of having been shot with stiff loads the last time around, it is important to either "thunk test" each one or the better approach is to individually measure them before the next reload cycle to make sure they haven't grown beyond .5015 in diameter, as measured after resizing, at the widest point. That is usually consistent with the area just above the web. They can look pristine but if they're too fat, the momentum of the bolt shoving them into the chamber, already tight, will compound once the next load is fired. I mic every case I process and put them in like diameter jars. IE <.5000, <.5005, <.5010 and less than .5015. Anything beyond .5015 goes into the recycling brass box. Nothing worse than being at the range and getting one stuck, which is a good reason to take your cleaning setup, including one-piece rod, in case you need to push one out. Ask me how I know this...

Even worse is having to pull down loads you didn't check first. Again, ask me I know this...

A third alternative is purchasing a chamber gauge to quick check them in. Faster than mic'ing them and lets face it, they either fit or not, regardless of the measured diameter. No fit = recycling.

Hoot

[offrink]

I agree with hoot. Every round of every caliber get put into a chamber gauge. Better safe than sorry.

[Smithjdsr]

I asked him. He has a chamber block for ‘plunk’ testing every round and normally measures ever 3rd or so for OAL. He loaded maybe 10 of these to test them, so he thinks he measured each one. The unshot rounds are all within spec. Maybe he should measure the brass length? It’s 450 Bushmaster, so there’s no shoulder and therefore nothing to “bump.”

Could it be that the case was too long? I don’t think he length trimmed them and he’s not sure how many times they’ve been reloaded. We were under the impression that straight walled cases don't really get too long- that they usually shrink. Could this be a problem with straight-walled cases? I’ve only used new or once-fired brass, but his is on at least the 3rd or 4th reload. Mine all measure within spec.

He says the case head doesn’t look swelled, but isn’t sure if the primer was flattened when he loaded it? He has a Rock Chucker, so I think you can put a good bit of pressure on the primer if you’re not careful. Says some of the un-shot rounds look a bit flattened.

I haven’t used my press for re-priming because I only have one primer arm and it won’t do both large and small primers. Not sure if Dad had both when he got it, but now there‘s only one, and not sure which one I have, but I use a Lee hand priming tool.

The loads were 225 grain Hornady FTX over 41.5 grains of Lil’Gun and CCI 450 primers, so pretty ‘hot’. I’ve been doing 38 grains of Lil’Gun. He’s not sure about the brass, maybe 4th or 5th reload. I don’t think they were measured after resizing- maybe a really bad idea! I told him that straight-walled brass doesn’t usually elongate, apparently it usually shrinks. Neither of us has a length trimmer, but the cases should still get measured.

Maybe all a moot point, now. He pulled all the remaining bullets. He’s going to re-process the brass and if they are out of spec, I guess he won’t use them any more.

[Hoot]

...snip...
The loads were 225 grain Hornady FTX over 41.5 grains of Lil’Gun and CCI 450 primers, so pretty ‘hot’...snip

Yeah, its hot but not rip snortin' hot. I doubt that would be a problem on the 1sr or 2nd loading. CHG is cumulative. They grow a little each time. If each of those times were similarly 41.5 pushing a 225, yeah those cases will grow to the point of binding. That's why I rarely load cases for my AR platform, more than 5 times. It not because the cases have deteriorated or even shrunk too much. They've just grown too fat by then.

There's no need to push those 225's so fast. They're designed for lower velocities anyway and plenty lethal at 2200 fps. If you hit another accuracy node further up in speed, that would justify the added umph but not needed if the accuracy deteriorates. Everyting's not necessarily better, the faster you push it.

Hoot

[Bmt85]

Yeah, I'm with Hoot. Most likely CHG. Get a micrometer to check. I suggest a blade micrometer.

With case length, you should always check it on the 450B. It usually shrinks, and they will hit a point when they are too short.

However, you can end up with a situation where you the case can grow, it's rare though. Even to the point it jams the rifle. I came across this when doing load work up with the 275 TSX in my Tromix barrel, using new Starline brass. I was trying to find how far I could push it. Well, a tight chamber, with new (soft) brass, and pushing pretty hard, ended up with a case that grew too much and jammed the action. Ended up having to mortar it. I also think that because Starline is thinner than Hornady, it added to the growth issue.

Anyway, when I load 450B, I check all measurements, especially case head growth. If something is out, I toss it.

[Bmt85]

Actually, I just went back and re-read your first post. You said that the case was stuck, couldn't get it out when cycling the action, but he used a rod to knock it out. I have a feeling the issue might be poor extractor tension. If the round fired, and the action cycled, but the case didn't extract (the extractor jumped the rim or torn that part of the rim off), when the bolt comes back forward, it or the next round it picked up, could have ended up pushing the case deeper into the chamber. It probably got deep enough to the point that it was stuck, and the extractor couldn't pop back over the rim. So it doesn't sound like the case grew, because that would jam the action, you would most likely have to mortar it at point.