I have a strange case and I would appreciate any insight. My rifle is clearly marked as having a .262" neck diameter, and was sold to me as such. For this reason, I turned my first rounds down to .0875" neck diameter, resulting in approximately .261" neck diameter on the loaded rounds.
Here's where things get strange. After firing for the first time, I notice that the necks are bulging. The case mouth is approximately .003" smaller than further down along the neck. What's even more disturbing is that when I got home and measured the necks, they all measure between .270" and .271". In addition, after seeing this, I tried to chamber brand new unloaded Lapua brass (about .268" neck diameter give or take) and they all chambered fine.
Is this all conclusive evidence that my rifle's neck diameter is NOT in fact .262" as advertised to me, and that it is in fact somewhere around .272"? Or, is there something funny when dealing with case necks that are thin that the brass somehow expands even greater? This makes no sense to me though, because the brand new Lapua brass fits.
I guess I'm just having a hard time understanding that a reputable gunsmith (I did not include the gunsmith's mark in the picture below, but this is a fairly big name custom rifle maker) would mark a barrel as having a tight neck when in fact it does not. It's easier for me to believe that my relatively limited experience reloading is to blame.
Any constructive insight is appreciated. If it matters, the rifle shot pretty well for the first time out with brand new reloads, even if there was too much neck clearance. My best 5 shot group was close to .5" at 100 yards.
Here's where things get strange. After firing for the first time, I notice that the necks are bulging. The case mouth is approximately .003" smaller than further down along the neck. What's even more disturbing is that when I got home and measured the necks, they all measure between .270" and .271". In addition, after seeing this, I tried to chamber brand new unloaded Lapua brass (about .268" neck diameter give or take) and they all chambered fine.
Is this all conclusive evidence that my rifle's neck diameter is NOT in fact .262" as advertised to me, and that it is in fact somewhere around .272"? Or, is there something funny when dealing with case necks that are thin that the brass somehow expands even greater? This makes no sense to me though, because the brand new Lapua brass fits.
I guess I'm just having a hard time understanding that a reputable gunsmith (I did not include the gunsmith's mark in the picture below, but this is a fairly big name custom rifle maker) would mark a barrel as having a tight neck when in fact it does not. It's easier for me to believe that my relatively limited experience reloading is to blame.
Any constructive insight is appreciated. If it matters, the rifle shot pretty well for the first time out with brand new reloads, even if there was too much neck clearance. My best 5 shot group was close to .5" at 100 yards.
