Ruger American gen 2 flat lines on brass

[Tiny Tim]

Looks like burrs around the back end of the chamber scratching the brass, I agree with previous posters. Box it up and send it back to Ruger. My gen 2 doesn't have any issues that I have noticed and so far, shoots very well with limited load development.

Looks like the lines extend over the shoulder and even onto the neck. Appears to be completely around the circumference of the entire case. Not likely a burr.

 

[Horse1]

"Into the lands" is usually measured in .001 increments, not something approximating COAL. (Grin)

Everybody knows about bbl twist, but, "What twist is your chamber" is a whole new rabbit hole…….

 

[Tiny Tim]

Everybody knows about bbl twist, but, "What twist is your chamber" is a whole new rabbit hole…….

Not sure, but assuming its different than the barrel.

 

[Bravo 4]

The one and only time I seen this the gunsmith said the reamer was probably "chattering" around when it was reamed. The rifle actually shot really well. He cut a couple inches off (custom .338 Edge) and re-threaded/chambered it and all was well.

 

[Rflshootr]

Reamer chatter. Send it back.

 

[Horse1]

That doesn't look like reamer chatter to me. That looks like the rifling (lands) are still there from the hammer-forging process. The chambers I've seen w/reamer chatter also usually ended up w/brass cracking on 1st/2nd firing either in the neck or right where the body/shoulder starts to taper into the neck.