Hi all,
I’m struggling with a frustrating issue and need help diagnosing what’s happening with my rifle.
I have a 6.5 SAUM barrel on a Bighorn TL3 action, which was once the most accurate barrel I’ve owned. It consistently shot bug-hole groups with any bullet and powder combination. I use it strictly for hunting, so it has fewer than 300 rounds through it.
Recently, I started using a new box of ADG brass and mounted a new Nightforce scope. Since then, the rifle’s accuracy has dropped significantly, producing groups just over 2 MOA, compared to its previous capability of 1 MOA for a 20-round group. I confirmed the scope is not the issue by testing it on another rifle, where it performed fine.
The main problem is that once-fired cases are getting stuck in the chamber during the second firing. I verified that the sizing die is fully sizing the brass to SAAMI specifications, and the new brass also measures within spec.
I’m observing signs of excessive bolt thrust. There are pressure signs on the brass, including loose primer pockets and excessive case head expansion, despite no increase in velocity. I’m seeing these issues with a load 4 grains lighter than my usual “go-to” load. The brass shows scuffing above the case head where it sticks in the chamber.
I’ve pulled the barrel, thoroughly cleaned it, and bore-scoped it to confirm there’s no carbon ring or physical damage. I also verified that the brass has no residual lube and the chamber is clean and dry.
Normally, I’d replace the barrel by now, but given its past performance, I’m hesitant to give up on it. Could something be wrong with the action causing this issue? Any ideas?
I’m struggling with a frustrating issue and need help diagnosing what’s happening with my rifle.
I have a 6.5 SAUM barrel on a Bighorn TL3 action, which was once the most accurate barrel I’ve owned. It consistently shot bug-hole groups with any bullet and powder combination. I use it strictly for hunting, so it has fewer than 300 rounds through it.
Recently, I started using a new box of ADG brass and mounted a new Nightforce scope. Since then, the rifle’s accuracy has dropped significantly, producing groups just over 2 MOA, compared to its previous capability of 1 MOA for a 20-round group. I confirmed the scope is not the issue by testing it on another rifle, where it performed fine.
The main problem is that once-fired cases are getting stuck in the chamber during the second firing. I verified that the sizing die is fully sizing the brass to SAAMI specifications, and the new brass also measures within spec.
I’m observing signs of excessive bolt thrust. There are pressure signs on the brass, including loose primer pockets and excessive case head expansion, despite no increase in velocity. I’m seeing these issues with a load 4 grains lighter than my usual “go-to” load. The brass shows scuffing above the case head where it sticks in the chamber.
I’ve pulled the barrel, thoroughly cleaned it, and bore-scoped it to confirm there’s no carbon ring or physical damage. I also verified that the brass has no residual lube and the chamber is clean and dry.
Normally, I’d replace the barrel by now, but given its past performance, I’m hesitant to give up on it. Could something be wrong with the action causing this issue? Any ideas?
