I recently installed a new Shilen Select Match barrel on my Savage 10 BA Stealth (6.5 CM, 1-8", 4 groove, ratchet rifling). So far I've run about 85 rounds through it and it groups really well. The first 10 were to break it in cleaning to bare metal after each shot.

I've been doing some load development and this weekend I ran 2-10 round ladder tests at 400 yds with some IMR 4451 I bought from Chad which went fine. After the ladders, I was shooting a 5 round group and the 4th round wouldn't chamber and neither would any of the remaining unfired rounds. Fired and unfired brass would chamber just fine. I brought it home and scoped it and found very heavy copper in the throat and also what looks like pieces of lead.

Its interesting that the groups did not deteriorate and 3 rounds just prior to the malfunction went into 1.3” at 400 yds (.31 MOA)

Something doesn’t seem right. What could be causing this? How should I remove the Copper/lead in the throat? Should I call Shilen or just clean it and try again?

Seating depth? My first thought would be you’re jamming the bullet hard into the lands. Look for marks on the bullets you tried to chamber. They should be obvious if they are there. If it’s not that, I would put my money on a sizing issue on the brass. I know you said empty brass chambers fine, but I would pull the bullets on the rounds that didn’t chamber, and see if those work as well. It could be possible during the sizing process your die loosened up and backed out a hair. It doesn’t take much to make a difference in chambering.

There’s a thread where I chased my tail on this recently. Everyone told me it was a sizing problem and I was sure it wasn’t so it was the last thing I checked. I was WRONG. Not saying that’s the case with you at all but my lock nut was loose and the die had backed out. First time it’s ever happened to me in years of loading but it happened.

I literally spent hours trimming and prepping brass again by hand because I was sure it was the lip on the federal brass I was using.

Yup.

First thought reading the O.P. was the bullet is jamming in the lands. Most often the case when brass will chamber, but bullet in brass will not.

Yes, I full length size and the brass will chamber with no resistance, loaded rounds will not. I created dummy rounds when I first installed the barrel that were set to touch the rifle lands and the bolt would close on them with no resistance. Now the bolt will not even come close to closing on those same dummy rounds even if I force it. Some of the rounds I've tried are set .040" off the lands and worked perfectly during the ladder tests and the bolt won't even close on them now. I'm sure its due to the excessive copper in the throat. The first pic I attached is not real clear but it gives you an idea of the thickness of the jacket material left in the throat. I'm wondering if there's something wrong that's causing so much jacket material to be left in the throat.

Look like it needs cleaned to me. Also looks like you have a donut you need to take care of and keep an eye on.

It has about 50 rounds since it was last cleaned, l would think it's not normal for that much jacket material to build up so quickly or at all. Not understanding your comment about the doughnut, please explain. The brass in new lapua on its 2nd firing so I wouldn't think it would have a doughnut already.

Carbon ring. It's the only time I'll get aggressive with a brush inside the barrel.

As JG mentioned....Carbon ring is the same as a chamber donut...it happens just in front of where the brass is in the chamber and before the rifling. I couldn't tell whether your brass has a donut without seeing that.

I called Shilen and they said its very unusual for one of their barrels to build up enough jacket material in the throat to prevent rounds from chambering especially after so few rounds fired. They suggested I clean it and let them know if it continues to do this. Hope I can get it clean without too much trouble.

waiting???

It cleaned up super easy, the copper in the throat came off in flakes one pass with a brush. Loaded rounds chamber fine now. I still don't understand what caused this. Hope it doesn't happen again.

What kind of bullets are you shooting?

This outing I was shooting 145 gr Barnes Match Burners and 142 gr SMKs and powder for both was IMR4451. The MBs were jammed .010" and the SMKs were .040" jump. MBs were the last 3 rounds fired just prior to the rounds not chambering.

I just got some 175gr match burners in 308 for a very similar set up, savage + shilen barrel. Don't know when I'll get to it but I'll keep this thread in mind and let you know if something happens.

Sounds like you have your answer based on the last 3 rounds fired. I have not heard of this specific issue but would not jam any rifle bullet. Wonder if the Barnes have a different copper alloy?

KR, so far accuracy has been good with the 145 MBs. Below is a "round robin" ladder test I shot with them prior to the chambering issue described earlier in this post. All 10 shots went into 2.54 inches (.6 MOA) at 400 yds, pretty good considering the powder charge was increased .1 of a grain on shots 1-5, shots 6-10 are duplicates of 1-5. Unfortunately the test did not clearly identify a node, I should have increased the charge by .2 grains instead of .1 grains. Afterwards I was shooting a 5 shot group with a similar load using the MBs that shot good at 100 yards, the first 3 went into 1.3 inches at 400. I got excited but was unable to fire the last 2 shots due to the chambering issue.

Agree, I'm not usually a fan of jamming but I got some feedback that they like to be jammed .010" so I tried it. Do you think that could have cause the jacket material build up?

I agree with big fitz.

Clean the barrel, back off the MB rounds so they're not jammed, and see if the issue persists. Sometimes you can get away with operating outside of the design range of mechanical systems, and sometimes you cannot. Seems you are in the latter.

If I ever did decide to jam them, it would be under 5 thousandths for sure. I'm not a benchrest expert, but 10 thousandths sounds like a lot of interference for a system like that - just from an engineering standpoint.

I haven't tried the MB bullets but the profile I would guess is one where some jump should be fine. I would seat them .015 or even .025 deeper for a little jump of .005 to .015.

I think Fitz and patriot are onto it.

I would for sure give it a try not into the lands.

Thanks for the feedback guys. I'll load some with a little jump and try them this weekend and post the results. Unfortunately it will only be 100 or 200 yds as I can't get out to my property this weekend.

100 or 200 will test for functioning.