Bullets sticking in chamber

[TexasShootR]

Last couple of matches my slide started hanging open or not returning to battery. I received a lot of suggestions on what could be causing the problem but after looking it over this is what I think.

Looks like its a bullet problem. Don't think I've been putting enough taper on my bullets and it has scored my barrel chamber. As I look into the chamber I see half round cuts all through the chamber. If I take a bullet and slide it into the barrel at the angle it would be chambered it will stick.

I'm surprised that brass would score a metal barrel if indeed that is what is happening. Anyway I spent a little time polishing the chamber and got some of the grooves out but not all. My question is, is this something anyone has seen before or am I off base with this diag.

Thanks,

Joe

[Hi-Power Jack]

What gun, caliber, type bullets (lead or jacketed)?

I'm guessing your OAL is too long -

Is the "scoring" bullet lube buildup?

More info would be helpful.

[bountyhunter]

I'm surprised that brass would score a metal barrel if indeed that is what is happening. Anyway I spent a little time polishing the chamber and got some of the grooves out but not all. My question is, is this something anyone has seen before or am I off base with this diag.

Thanks,

Joe

Surpises me too. If it was steel case ammo, I could see how. Is it possible the barrel has become surface annealed from heat in the throat area? Either that or it was not hardened properly when it was made?

I remember a barrel maker saying that people who shoot very fast strings can get the barrel surface hot enough to anneal it a bit.

Edited December 5, 2013 by bountyhunter

[TexasShootR]

Sorry about the lack of info.

This gun is new, maybe one thousand rounds through it. It shot fine the first 500 rounds but then at a local hybrid match (Generation 300) it started with this problem. A lot of shoting that day 300 rounds in eight stages.

.38 SuperComp

124gn MG CMJ

oal 1.225

VV 3n38 9.7gn. (1400fps)

Side note: When I set up this load the bullet measured 1.225 col but at some point (500 rounds?) the lenth changed and it measured 1.255 col. I corrected this back to 1.225 and reshot it and the gun still wouldn't cycle.

It will now hang open by just chambering a round by hand.

Here's some pictures

One person thought the extractor might be to tight

this scatch comes from the top of the ramp when it gets stuck

I can slowly slide the bullet in the barrel and it gets stuck at this point

Here are the scratches in the barrel, This is after a guick polishing.

Would like to add this gun was set up as a SuperComp, because I'm new to Open division and to .38 SuperComp I didn't know .38 Super brass was different than .38 SuperComp brass. So I ordered all Super brass. I was told it would be ok to shoot with the Super brass. And like I said it was fine for a while.

[Hi-Power Jack]

Sounds like your ammo will NOT chamber check (drop round into chamber - out of gun)??

But, I'm more concerned with scoring in chamber - I have NO idea what caused that -

let's wait for an expert to come in on that issue ...

[TexasShootR]

I do chamber check every round through a dillion gauge. Also the round will fall in the chamber with no problems if you drop it straight in.

[Powder Finger]

extractor tension will be higher with 38super cases.

[Jediwarrior]

extractor tension will be higher with 38super cases.

If your rounds will drop into the barrel with no hang ups, then the FTF is probably caused by tight extractor tension on your AFTEC extractor with standard 38 Super (semi-rimmed) rounds. Whether the hanging up caused the rings in the chamber, or the rings were already there from the start due to a dull chamber reamer, that is the question.

[frankie]

don't trust the case gauge. I shoot 9major and have several different brands of case gauges. If I check 100rds in dillon case gauge all fit then I use an old gauge from midway I have about 5% that don't fit. If it's an important match which they all are I use my barrel.

[cohete]

From your chamber photo, it looks to me like the chamber was scored by the chamber reamer. I general chamber a barrel on a my lathe, which will align the barrel perfectly with the chuck that holds the chamber reamer. I turn the lathe at a slow speed and use plenty of oil during the cutting process. I also back out the reamer regularly and clean the chips during the process.

I have never seen a chamber in that bad shape. I do not believe that the actual loaded cartridge is capable of causing that damage to the chamber.

The chamber reamer enters the barrel into the rifling part and aligns itself to keep it from wobbling.

Are those marks just on the top of the barrel, or are they all around the chamber

[Zoomy]

don't trust the case gauge. I shoot 9major and have several different brands of case gauges. If I check 100rds in dillon case gauge all fit then I use an old gauge from midway I have about 5% that don't fit. If it's an important match which they all are I use my barrel.

+1 I had a failure to chamber on a round that was case gauged and found to be ok. Turns out my Schueman barrel has a tighter tolerance and will not chamder a round that is on the high side, even if it is within industry specs. I am using gauge pins to find out the exact diameter of my chamber and machining a case gauge that is .0005 smaller to check my rounds.

[TexasShootR]

"are those marks just on the top of the barrel, or are they all around the barrel"

It seems to be more on the sides and top but before taken the picture I took some very fine wet dry sand paper and sanded it with a dowel rod and a drill. It polishes the bottom of the chamber more than the top and sides.

Edited December 6, 2013 by TexasShootR

[TexasShootR]

Update, today I did a little more polishing of the chamber and I also removed one of the springs on the Aftec extractor. Took it out to the range and put about 50 rounds through it without any FTF. Won't be sure if its 100% fixed untill next match but it did well today.

Thanks to all that replied with suggestions.

[Ming the Merciless]

don't trust the case gauge. I shoot 9major and have several different brands of case gauges. If I check 100rds in dillon case gauge all fit then I use an old gauge from midway I have about 5% that don't fit. If it's an important match which they all are I use my barrel.

A case gauge properly sized to your chamber is the best method. Rounds with rim damage or a fish belly bulge MAY drop into your chamber IF oriented correctly (incorrectly?) but not drop in if rotated a quarter turn because the chamber does not fully surround the case all the way to the rim. If you're lucky at the big match it may chamber in the correct orientation to fully chamber, if you're not it will be that quarter turn off that jams up your gun.

Drop a fired case into your case gauge, if it drops in, the gauge is oversized for your chamber. If the fired case does not drop into the case gauge, it is smaller than your chamber and anything that fits the gauge will fit your chamber.

[goldfieldshooter]

If that gun was mine I would be sending it back to STI or the builder. That is chamber reamer damage and the barrel should be replaced by the factory.There is no way ammunition can cause that damage even with filthy dirty cases. Cases go in and they come out. They don't rotate in the chamber and they are marks from something that has rotated ie. chamber reamer!

My 2c

Coatesy

[Silver_Surfer]

355 or 356?

[bountyhunter]

That's the worst looking barrel throat I ever saw. The cuttter they used was totally hosed. I would also want a new barrel from whomever got my money.