So,  I have a Noveske barrel in my 300Blk, and using a to spec piece of brass and a borescope, I can see that there is a sizable gap between the front side of the brass and where the chamber stops and the leade starts.

The issue is that the edge is pretty sharp on that chamber lip, and when I am attempting to shoot some powder coated cast bullets, that lip is shaving off powder coat and lead, and building up a ring there that after just a few rounds makes it so that the rounds stop chambering properly.

What would you suggest ti maybe chamfer that lip a bit so that it stops shaving the projectile?  Making a die from a chamber casting is probably the "best" solution, but curious if there are other suggestions for this.

Thanks!

I'd dump a mag of the cheapest bullets I had through it (non-lead) and see what it looks like.

I've put hundreds of copper jacketed stuff through it without issue, its just with the cast stuff I am having issues.

While yes, I could keep shooting jacketed bullets, given availability these days, being able to shoot cast also would be a good thing, so trying to resolve that.

How about running the cast bullets through a sizing die that is slightly smaller then the barrel "sized" diameter?

You could try using a case as a holder with some kind of abrasive coated bullet chucked in a drill, but you run the risk of destroying the barrel.

I am still somewhat new with the cast bullet thing, but I am told that too small a bullet leads to gas cutting up the sides and bad leading in the barrel.

These have all been run through a sizing die to put them to the right diameter.

Since the cartridge is not headspacing off of the neck I think chamfering that is going to work best.  Worst case I turn some tool steel to diameter and make a small cutter to break that edge some.

Cheers!

I saw a thread with this exact problem recently but it’s probably archived and unavailable now. My PSA barrel is the same way. Can you trim your brass longer to fill the void? Another option would be to somehow taper that sharp edge but I’m not sure how to do that. Perhaps a brass screw sized to .312 or so and valve grinding compound??

What are you sizing your bullets to now? I tried .310 but they didn’t fit the throat. .309 seems to be what most people are doing.

Hmmmmmmmmm...... Attached File

.309 is what my sizer is.

I could trim the brass longer, but then I am gonna have issues with it being out of spec and not usable in any other 300blk. :(

Tried to make a reamer this weekend to clean up that lip a bit, but it did not work as planned, so gonna have to make another I think.

If you figure something out, post some pics of what tool you made and the results.

I have a way that works for smoothing it out a little but I don't think it will remove enough material to correct this issue. It might I don't know.

Use a case with the case head removed as a chamber guard and a flex-hone polishing brush set so that it can't go too deep into the throat.

That's a fairly ingenious setup with the case.  I suspect the brass will prevent me taking enough of that lip off, but I will file that idea away from later, it sounds useful.

That was a while back and I'd forgotten exactly how it was done... casehead wasn't removed, just drilled a giant hole through the primer pocket almost as big as the case interior, so that the rim was left in place to be able to be removed easily.