A new-to-me RRA BT3. I'm still troubleshooting the root problem, but I noticed this about all of the spent brass.
The two scratches appear to be from the lugs on either side of the feed ramp. The dent appears to be happening during extraction. It's hard to tell from the picture, but it is smoother near the base and then sharper near the neck, like the metal is being gouged deeper as the brass extracts. It appears that way on every round, so it looks like the scratches don't matter which side the round loads from, but the dent is always on the left scratch.
The bigger issue, whether or not related to the brass, is I've been having rounds not want to chamber. This did not happen at all on my first outing, where I was sighting in the irons. I was using a mix of FN and MAL ammo. In most cases, I loaded 5 or 10 rounds per magazine for sighting. I used two PMAGs and a steel factory magazine.
In the second outing, it was only MAL ammo, and I had installed a scope, torquing the cross screws to 60in-lb. In all cases, it's happened where I push the bolt release on a fresh magazine of 5 rounds. Normal firing and cycling had no problems. To get the round out, I had to mortar the rifle on the bench. Same magazines as the first outing.
The first outing was a mix of FN and MAL ammo, with the same marks. The second outing was just the MAL ammo, maybe 5 rounds out of 80. Same mix of magazines. So, the only real difference between the two outings was adding the scope.
Plans for my next trip, whenever that may be, will include trying different ammo and loading rounds with the charging handle instead of the bolt release, and also trying single feeds directly into the chamber. I've measured the next set of MAL rounds and compared them to some Hirtinberger, and found no differences.
The two scratches appear to be from the lugs on either side of the feed ramp. The dent appears to be happening during extraction. It's hard to tell from the picture, but it is smoother near the base and then sharper near the neck, like the metal is being gouged deeper as the brass extracts. It appears that way on every round, so it looks like the scratches don't matter which side the round loads from, but the dent is always on the left scratch.
The bigger issue, whether or not related to the brass, is I've been having rounds not want to chamber. This did not happen at all on my first outing, where I was sighting in the irons. I was using a mix of FN and MAL ammo. In most cases, I loaded 5 or 10 rounds per magazine for sighting. I used two PMAGs and a steel factory magazine.
In the second outing, it was only MAL ammo, and I had installed a scope, torquing the cross screws to 60in-lb. In all cases, it's happened where I push the bolt release on a fresh magazine of 5 rounds. Normal firing and cycling had no problems. To get the round out, I had to mortar the rifle on the bench. Same magazines as the first outing.
The first outing was a mix of FN and MAL ammo, with the same marks. The second outing was just the MAL ammo, maybe 5 rounds out of 80. Same mix of magazines. So, the only real difference between the two outings was adding the scope.
Plans for my next trip, whenever that may be, will include trying different ammo and loading rounds with the charging handle instead of the bolt release, and also trying single feeds directly into the chamber. I've measured the next set of MAL rounds and compared them to some Hirtinberger, and found no differences.