450 bushmaster question

[bigred94]

I just put together by 450 bushmaster build. The barrel is from bison gun works. Long action with 06 bolt head. Set headspace with ptg gauges. Now to the question. Something is eating up the rim on the cases. Doesn't mar them every cycle but about every other one. Have not shot gun yet just cycling factory hornady ammo through it. You can feel it hang up sometimes on something and bolt has a hard spot on it when closeing. When it's ejected you can see mar spot on rim.


What's going on???

[bootsmcguire]

What kind of action are you using? CF or SF?

I am betting its your extractor when it snaps over the rim but just a guess at this point. A stiff extractor will feel like it catches on the brass just as you start to push the bolt handle down, or slightly before that.

Pictures of your brass' rim and bolt face may prove to be useful for us.

[bigred94]

SF.

Never posted any pics before. How do I go about doing that?

[bigred94]

Don't have computer just iphone

[clintsrv]

Get the Tapatalk app. You can post pics using it directly from your phone.

[bigred94]

Maybe these are clear enough for someone to see what's going on

[bootsmcguire]

Hard to tell from the pics, but appears that is from your extractor. Does the extractor move freely (obviously with some tension from the ball detent underneath) in the dovetail grooves?

[bigred94]

It moves pretty freely. In the second pic you can see the mar just to the right of center of rim. It seems to do when closing the bolt.

[earl39]

I'm with boots on this but just to make sure check your bolthead and look for any burrs on the inside edge. Also measure the OD of the rims and see if the ones that have the mark are 1 or 2 thousands larger than the ones that don't get the mark maybe even as little as 1/2 thousands. It is not something that will hurt your brass but i understand the wanting to get everything working right.