I hope someone with a chonograph can help clear something up for me. I have a 7.62x51 ex-Israeli 98k Mauser (sporterised) that was showing pressure signs with some (not all) Winchester factory ammo (slightly stiff bolt lift, bright extractor mark on head). Doing some investigation it turns out this rifle has a short throat and factory ammo in/on the lands. (Headspace is also on the long side of 308W spec, but in spec)
So I have seated my factory ammo 100 thou deeper and I have been making my reloads about 100 thou off the lands and all is OK with compressed loads of Varget (AR2208) and 150gn Hornady SPBT.
I'm curious what this will this do to velocity (not that a fallow deer will care)? I read some places velocity can drop by 100fps or more. Other references show negligible drop in velocity. Not having a chronograph myself, when I get a chance I was thinking of comparing point of impacts at 100yds & 300yds to get an estimate of velocity variations.
Has anyone already tested velocity & seating depth?
I'm not too worried about extreme accuracy (getting about 1 moa @ 100yds - again a fallow deer won't care). Would seating say 50 thou off the lands (and not crunching my powder so much) get better velocity without too much more pressure? How close to the lands does pressure start increasing?
(attached pic is Win factory Power Point 150 gn)