Remington 700 .308 (Factory)
I am new to this forum so I hope this is the right place to post this. I bought a new Remington 700, .308 with a 20" Tactical Barrel - 1:10 twist. Has a Weaver T-Series 36 power scope on it. The gun shoots terribly at anything other than 100 yards even with hand loads. Factory loads were 167, 168 & 175 gr Lapua, Federal & Black Hills in that order. I measured the case neck OD after firing at ~0.345". This is about ten thousandths more than a loaded factory cartridge neck size OD, (average I measured betwen Federal, Black Hills and Laupua was about 0.335 - 0.338" depending on manufacturer). It is so wide that I can drop a bullet into the fired catrdridge! Never had a .308 before. I am a 6.5mm Creedmoor enthusiast at the moment.
I am asking you .308 experts if this is excessive exapansion or is this normal for a factory chamber?
BTW, I plan on replacing the barrel with a custom one, but I just wanted to know. My goal is improved accuracy out to 600 yards. I know what does improved mean? OK, 1 MOA at 600?
Thanks in advance for any advice / help you guys can provide.