I loaded and shot a very narrow ladder (8 rds) as I knew the approximate range I wanted to be in. This brass has been shot a lot during testing. I've re-used the sames cases instead of cracking into my cache of new brass. As I primed them, I discarded 2 cases and said this is the last loading on the other 6. Primer pockets weren't totally loose but not as snug as I like. I substituted 2 new cases and charges them with the 1st 2 increments. I'm only increasing charge weights by .1 as I'm pretty locking into a specific charge range. The 1st 2 rounds at 300 yds went into the same hole then when I hit the used brass they opened way up and moved up and left. I've shot enough ladders to have seen a lot of things happen with barrel harmonics but it really got me wondering if the last 6 were the cause of just flat out worn brass. I'm going to re shoot the 6 with new brass but has anyone seen something like this? Rifle is 6.5 SAUM/GAP and is a hammer.