This Has Me Worried. Broken BLK Brass

[dragon813gt]

Work hardening occurs when you bend the metal repeatedly. When you bend a paperclip till it breaks, you have work hardened that till it became brittle.

Correct me if Im wrong guys, sometimes I miss.

You're correct. Forming this case is easy. But since you're cutting off the existing neck you are into a part of the case that wasn't annealed previously. Some like to anneal doing any work. I do it as the last step because cases that fail during forming will fail when fired. This isn't a complex conversion where you have to anneal to keep the cases from failing.

[jblee10]

I don't think you folded the mouth during bullet seating. I think you would have felt it, and there would still be some marks on the case after firing. Once fired brass would be hard and brittle in this area. Also, it may be stretched if subjected to excess headspace. But your pictures show no evidence of that. That is USUALLY further down toward the case head anyway. Do any of your other cases show dings on the mouth from ejection? They may be hard enough that they show very little bending, and just break instead. I think annealing will fix the problem. I anneal BLK before forming, but it sounds like annealing after forming works just fine. It may even be better.

[Jayhawkhuntclub]

If I'm understanding this correctly, this was just ONE piece of brass that was like this? If so, I wouldn't give it another thought. If it keeps happening, I'd try corrective measures.

[BulletFactory]

I think I found the issue. It wasnt folded in, I would have seen it. Not trying to be bold, but this is a new gun, 250rds, and Im in load development, so I am watching things very carefully at this stage.

The bullet diameter is .312, and after several rounds, a ring of lead forms in the chamber. Every now and then, I had to use the forward assist to get it to fully chamber. I hadnt isolated the problem yet. I think it was self clearing now and then, and would build up again. I was measuring bullets, case dimensions, gas checks, bullets checked, bullets unchecked, neck diameter, chamber diameter, and was even turning the necks in a neck uniforming tool. I had taken the upper off, and checked the bore, anything I could think of.. Well, last night, I was looking into the chamber area, and thought, "this doesnt look right" and ran a brush through from the muzzle first, which I almost never do. And there it was...A lead ring.

That would explain a lot !

A few years ago, I was trying to load for my first gun, an XD.40 sub, and had this problem. I'd started a thread called "Chamber Shearing". I found these little lead rings in the chamber, they were keeping it from going into battery. It was a very in depth thread, you could learn a lot there. Geargnasher really got it figured out, and I still thank him (and others) for their thought, time and input in the thread. I ended up getting a custom expander made from someone here, but I forgot who that was. It goes in the LEE powder through die, and Im still using it. And a custom push through sizing die which came out to .4015, after a little work.

Anyways, the bullets were just a little big and as they were starting to enter the throat area, would shear off just a tiny bit of lead, causing a buildup where the case should rest for correct headspace in a pistol. My blackout is doing this to me now.

I think that getting a LEE custom sizer at .309.

Would clear this up in the blackout?

What do you think?

[BulletFactory]

I had zero leading in the bore, but the BCG was so caked with lead, I had to hold the bolt in a vice in order to yank the bolt out of the carrier. I had to take the gas rings out of the bolt and lightly sand the lead off of each one with 600 grit paper. I had to wire brush the bolt because there was such a heavy layer of lead "soldered" to it.

Is this a side effect of the same problem, or something new???

Yes Jayhawk, it was just one piece of brass.

[runfiverun]

I'm kind of surprised you can even chamber a 312 boolit.
in my bolt guns I can't even chamber LC brass with a 310 boolit I have to either turn the necks or use different brands of brass.
switching to a smaller diameter boolit could help, a little harder alloy could help also.

[dragon813gt]

If you have to use the forward assist there is a problem. Don't force the bolt home and make it even worse. I omitted the FA from my last build because it's not going into combat. My life doesn't depend on it so I don't want to make a problem worse.

[BulletFactory]

It did help me isolate the problem though.

ETA All of my guns might go into combat someday. Thats what the Second Amendment is for.

[popper]

Definitely pad the deflector. I sometimes get a scrunched neck when sizing - the ball removes it - so you don't see it. As it is a formed case, could have been a bad one to start. That boolit needs to be sized to bore to get it to feed and not leave the lead ring. BO has a long throat before the lands, your ogive is scraping the edge of the bore. 312 is way big for BO, my loose neck takes 310 and tight is 308. All my moulds are FN and feed fine - you need to play with the OAL some.

[BulletFactory]

When annealing for the .308, I used a temp crayon and spun the brass in a drill, the dropped them in water. I was always concerned about doing it wrong. I actually hated annealing because of that.

What method would you guys recommend? Im not liking the water pan/tip over method, cant get even heat that way.

Im not buying an annealing machine, Im broke. Pretty much have to use whats on hand.

[JRPVT]

Also betting on post #15. Work hardening means just that. Whether you bend it, push it, pull it, hit or work it in any way, it puts stress into the structure. Heating brass relieves that stress, annealing. Which is why many shooters only neck size their brass, it will last a long time.

So, flare the brass a hair more and gently touch it with a chamfer tool. Then anneal, load them up. Dave

[dragon813gt]

Socket in a drill if you don't want to buy an annealing machine. You will not have repeatable results this way. Don't get me wrong, it works. But each case will be annealed slightly differently. This is the method I used until I bought a machine.

Water is not needed for the process. All it does is allow you to handle the cases quicker. As soon as you remove heat it stops. It won't make it's way down to the case head to destroy it. This is assuming you didn't get the neck to a cherry red state.

There are a bunch of affordable annealers available now. I have an Annealeez. I think Mike's Reloading Bench sells them. There are a couple more of these designs available.

Here is mine doing its thing: http://s198.photobucket.com/user/dra...F8A_1.mp4.html

[high standard 40]

When I saw the picture, I had an idea of what was the cause and was going to post my thought but I see 243winxb beat me to it.

[yondering]

Careful with those lead rings, and continuing to fire more rounds with a ring already there. I think there are several potential causes for this, and sometimes they could raise pressure dangerously.
Sizing too large, as you mentioned, can do it, as can using lead alloy that is too soft for the load. Inadequate lubrication can do it as well; not all powder coating is equal and some is not as slick as others.

Regarding the lead build up in your bcg - is that a plain base powdercoated bullet you're using for supersonic loads? If so, that's the problem - you really need gas checks for supers in a gas gun. Some guys will swear it doesn't happen, but localized gas cutting can and does happen as the bullet base passes the gas port, blasting lead into the gas system as you've discovered. You should be fine with subsonics plain based, but the high pressure of supers is a problem in this regard, and accuracy suffers too. Excessive crimp can also scrape the coating off and expose lead that gets in the gas system.

I use a deep socket in a drill for annealing; stuff some paper towel in the socket so the cases sit in it with the right amount of shoulder sticking out. Don't heat the brass until you see red, that's too far. If you watch carefully in good light, the brass changes appearance slightly at the right point for annealing; the surface takes on a "melted wax" appearance, almost like it's wet. Remove the flame right at that point; with my torch it's about a 2 or 3 count to get there with most cases.

[BulletFactory]

I stayed away from the gold rings too.

I am using gas checks on them.

Harbor freight powder coat.

I would really like to continue casting for this thing. Buying copper jacketed is equivalent to admitting defeat.

Can I shoot PC through the AR without screwing up the BCG every couple hundred rounds?

[Omega]

I stayed away from the gold rings too.

I am using gas checks on them.

Harbor freight powder coat.

I would really like to continue casting for this thing. Buying copper jacketed is equivalent to admitting defeat.

Can I shoot PC through the AR without screwing up the BCG every couple hundred rounds?

HF PC is OK, black is the only one I have heard some have issues with, but no solid evidence that the issues were due to the PC. Your BCG should not be affected, if any issues it would be your chamber throat.

[yondering]

I stayed away from the gold rings too.

I am using gas checks on them.

Harbor freight powder coat.

I would really like to continue casting for this thing. Buying copper jacketed is equivalent to admitting defeat.

Can I shoot PC through the AR without screwing up the BCG every couple hundred rounds?

Yes, but in my experience - the Hobo Freight powder coat and the excessive crimp aren't doing you any favors. It really is worth buying better powder, and even expensive powder is pretty cheap since you get so many rounds coated. RAL 6018 Yellow Green from PBTP is a good choice if you need a suggestion; I use it in 300 Blk, 30 Herrett, and 308 AR rifles up to ~2800 fps with great results and no lead buildup in the bcg or anywhere else.

[BulletFactory]

Oh I fixed the crimp thing.

[ironhead7544]

I would get an M die for the Blackout with cast bullets.

Try a magazine that is made for the 300 Blackout. That may cure your feeding problems. Varying COL might also work.

[John Boy]

Once fired, converted from .223. This one was stamped AGUILLA 223 REM

* When cases are reformed, the brass is work hardened
* Then if the cases are not annealed, compounded by the work hardening & fired at higher pressures - the metal in the cases is over worked more - results can be the mouth is gone or split cases

It's always best to anneal - reform the case - anneal, then reload
If you want to learn a brass molecules hardening, buy Lyman's Cast Bullets book ...
https://www.amazon.com/Lyman-Cast-Bu...ds=lyman+books