Shoulder bump

[Texas Solo]

My chamber is tight on my new 308. Even factory Fed GMM gives me a tight bolt closure. I bumped the shoulder .002" but it's still tight but slightly better.

Question is how much bump is safe?

[Whynot]

You bumped the shoulder on the factory ammo? Or are you talking once you fired?

More information is needed to understand what you are talking about. Are you sure it is tight on the shoulder- and not that you are jamming the bullet?

[CFJunkie]

I had a similar problem with two new .308 Savage barrels in 2011.
Both bolts wouldn't close easily on .308 Federal GMM rounds.
Turned out that the new barrel chamber depths were 0.006 short of the 2.800 SAAMI OAL spec and the GMMs were around 2.796 OAL.
I put the factory rounds in my seating die and moved them back to 2.793 OAL and the bolts closed easily.
On my rifles, it wasn't the shoulder, it was the bullets being shoved into the lands.

After 100 rounds fired, the bolts closed easily on all factory ammo.
Those two rifles now have over 4,000 rounds down their barrels, and they still shoot as well or better than new.

[Texas Solo]

Problem is with BOTH factory Fed GMM 168 and new sized & trimmed Hornady brass.

I measured the CBTO with a Hornady Guage and minused .005", so no, the bullet isn't jamming.

[CFJunkie]

It is possible that the reamer for the chamber was mis-adjusted and didn't go deep enough.

Savage is pretty good at quickly fixing those kinds of problems.
They took less than two weeks to rebore the chamber on my 12 LRP that was too tight and caused high pressure signs, even on loads that were at the minimums on the load table. Of course, I had to send my rifle back but they paid shipping both ways.
That problem was probably caused by a well-used reamer that had used too long.

[PhilC]

How does the bolt close on a new, unsized, empty, Hornady case?