Marks on bullet. What is going on here?!?!

[milo-2]

Did you by chance fire some Hornady factory rds through this? Though the smith with a borescope should have picked it up, I suspect carbon ring. If the part of the barrel that accommodates the bearing surface part of the bullet was cut too small, I wouldn't think the hornady oal tool could push through it w/o breaking it.

 

[milo-2]

The bullet slides freely in and out of the case with no resistance. I don't see how it is what is scratching the bullet.

Easy test would be to tip the barrel down and drop a bullet in the chamber, use a rod to push the bullet in place, eliminate the modified case, but I am with you on this.

 

[alarcher]

Easy test would be to tip the barrel down and drop a bullet in the chamber, use a rod to push the bullet in place, eliminate the modified case, but I am with you on this.

I thought about doing that same thing. I'll try it tonight.

 

[alarcher]

Did you by chance fire some Hornady factory rds through this? Though the smith with a borescope should have picked it up, I suspect carbon ring. If the part of the barrel that accommodates the bearing surface part of the bullet was cut too small, I wouldn't think the hornady oal tool could push through it w/o breaking it.

yep I did. I was getting ejector marks on some of the factory loads too. Not as bad as the reloads but there were still signs time to time.

 

[Rardoin]

Have a Cerrosafe cast made of your chamber and the diameter of the freebore can be precisely measured.

 

[milo-2]

yep I did. I was getting ejector marks on some of the factory loads too. Not as bad as the reloads but there were still signs time to time.

I would put money on a carbon ring being your holdup, that ammo notorious for it. Get a 7mm brush, some solvent, find a way to chuck a rod up in a cordless drill and work that area over.

 

[26Reload]

As others are diagnosing poorly cut chamber..if the bullet is loaded to a minimum coal there would be no lead..straight into the lands from the case mouth?
How many shots..lets see a pic of the lead and lands area...

 

[skipglo]

That's why I also asked what form the case was in. The case mouth might be scraping the bullet if it's being pushed all the way up it. We need more info.

Good answer! I'm with you. Unless the OP is spinning the bullet the lands wouldn't give a circle...

 

[Tiny Tim]

Hard to believe it's a carbon ring if the smith didn't notice it with a bore scope. I'm with the others who suspect a worn or bad reamer. Since it happens with both handloads and factory ammo, it should rule out the bullets themselves.

 

[7mmTikkaShooter]

I'm going to go with the worn reamer camp. You really should contact Christensen with this because I'm guessing it's not the only chamber cut with that reamer. If that is indeed the case they should hopefully track down others built with the same tool. One question I have though; did you confirm measurements on the bullet lot you're using? Stuff happens in manufacturing and is it possible bullet diameter is not what it should be? Say some .277 got mislabeled into a 6.5 box etc.? Very unlikely but heard of crazier things happening. You get the idea. Just a thought and a quick test to try.

 

[Shane Lindsey]

Have you tried it without the modified case?
Are the marks uniform around the entire bullet or just on one side?

If not, try without the case and push it up to the lands with a cleaning rod. Then take a look at it.

I have seen this before, but only on one side of the bullet, like it was dragging in the bottom of the chamber before engaging the lands.

 

[alarcher]

Just tried this without a modified case. Same result. Uniform marks all the way around. I also tried intentionally scratching the bullet using the case by trying to mimick the bullet sliding out of the case. The case is not doing this.

 

[alarcher]

I'm going to go with the worn reamer camp. You really should contact Christensen with this because I'm guessing it's not the only chamber cut with that reamer. If that is indeed the case they should hopefully track down others built with the same tool. One question I have though; did you confirm measurements on the bullet lot you're using? Stuff happens in manufacturing and is it possible bullet diameter is not what it should be? Say some .277 got mislabeled into a 6.5 box etc.? Very unlikely but heard of crazier things happening. You get the idea. Just a thought and a quick test to try.

Yep thought that too. All the bullets meet spec. Gun is on the way the Utah now.

 

[Rardoin]

Looks like a tight freebore. They need to cast the chamber/FB and get out the mics.