Chamber clearance issues.

[ronemus]

To the question about contact points on the brass, it isn't consistent all the way around. I would say where it touches is random and varies in length and depth of contact.

Factory brass usually has some variation in neck thickness, so you would expect the contact to be spotty. I'd suggest starting with a few pieces of brass and turn off 0.002" so you can be sure of adequate clearance, then measuring the neck diameter after they're fired; that should give you a good idea of the diameter of the chamber dimensions. Given how close the clearance is, I wouldn't shoot any factory loads at all until you have a better idea of the chamber dimensions.

 

[codybrown]

I don't have any factory ammo, so no issue there. I don't have a neck turner, I'll be looking at options tonight.

 

[Ringostar]

If this barrel has been fired you might check for a carbon ring at the end of the case mouth also.

This is what Im thinking from the original post. If the chamber was cut too long to start, you could have a carbon buildup. Since you moved barrel back by thinning the lug, your brass could be contacting a carbon ring now. I would also check your bolt to barrel clearance now.

 

[Benchrest Braxton]

This is what Im thinking from the original post. If the chamber was cut too long to start, you could have a carbon buildup. Since you moved barrel back by thinning the lug, your brass could be contacting a carbon ring now. I would also check your bolt to barrel clearance now.

how would you check bolt to barrel clearance?

 

[xr650rRider]

how would you check bolt to barrel clearance?

Was in Tony Boyer's book "The Book of Rifle Accuracy". He suggested solder on opposing sides as bolt might cock to one side slightly.

https://forum.accurateshooter.com/t...at-your-bolt-nose-clearance-measures.3994271/