Hi guys, I hope you can help. I have had a lot of POI shift problems lately, and it is really starting to p--- me off!
My rifle is a 6mmARTurbo- almost identical ballistically to a 6mmBR- except chambered in an AR-15 type rifle. I was using the Berger 108grain boattail over 28.4 grains of H4895 for a velocity of about 2800fps. This combo has proven to shoot typically under .4” at 100yd (5 shot groups). Previously I had been using the 105 AMAX over 28.8grains H4895. That combo has proven to shoot typically under .5” at 100yd (5 shot groups).
On Saturday I participated in a little friendly “match” that ranged from 100yards to 500yards. I used the 108 grain BT load. The second stage was at 100yd. (pool balls) and this occurred at about 7:30 AM with a temp of about 85 degrees. My zero had been dead on at 100 yd. one week prior at 100 degrees temp. (about 10:00 AM). On the pool ball stage my impact was at the 10:30 position, about 1 inch out (high- left). I made adjustments to compensate at this time. Within 1 or 2 hours the rifle was back to shooting at the original zero. By this time (9:30 AM) the temp was about 97 degrees.
Previously I have done some testing with my 6XC bolt gun to see if the direction of the sunlight is causing POI shift. My findings were that the direction of the sunlight has no effect.
After our friendly “match” I re-zeroed the rifle at 100yards, shooting a .4 MOA group (3 rounds). Then I immediately engaged the 500yd steel. I was missing right on the steel by about .75MOA so I cranked left. Mirage was boiling when I sent the rounds at 500yd. After the correction my group was good, with 4 rounds going into under 3". Then I engaged 100yd paper. Back to missing left by about .6 MOA. I tried again and the shift was exactly repeatable. I cant believe that I am getting that much spin-drift at 500 yards. WTF?? When I was using the 105 AMAX I didn’t seem to have any issues with spin drift out to 500 yards.
What scope am I using? 16X “Super Sniper”. Yes, I know – I know…. (hanging head in shame). I am still waiting for the PSTs to come in.
I used a torque wrench to properly tighten everything. Scope mount is the new Burris AR mount.
Thanks so much for any input / suggestions.
My rifle is a 6mmARTurbo- almost identical ballistically to a 6mmBR- except chambered in an AR-15 type rifle. I was using the Berger 108grain boattail over 28.4 grains of H4895 for a velocity of about 2800fps. This combo has proven to shoot typically under .4” at 100yd (5 shot groups). Previously I had been using the 105 AMAX over 28.8grains H4895. That combo has proven to shoot typically under .5” at 100yd (5 shot groups).
On Saturday I participated in a little friendly “match” that ranged from 100yards to 500yards. I used the 108 grain BT load. The second stage was at 100yd. (pool balls) and this occurred at about 7:30 AM with a temp of about 85 degrees. My zero had been dead on at 100 yd. one week prior at 100 degrees temp. (about 10:00 AM). On the pool ball stage my impact was at the 10:30 position, about 1 inch out (high- left). I made adjustments to compensate at this time. Within 1 or 2 hours the rifle was back to shooting at the original zero. By this time (9:30 AM) the temp was about 97 degrees.
Previously I have done some testing with my 6XC bolt gun to see if the direction of the sunlight is causing POI shift. My findings were that the direction of the sunlight has no effect.
After our friendly “match” I re-zeroed the rifle at 100yards, shooting a .4 MOA group (3 rounds). Then I immediately engaged the 500yd steel. I was missing right on the steel by about .75MOA so I cranked left. Mirage was boiling when I sent the rounds at 500yd. After the correction my group was good, with 4 rounds going into under 3". Then I engaged 100yd paper. Back to missing left by about .6 MOA. I tried again and the shift was exactly repeatable. I cant believe that I am getting that much spin-drift at 500 yards. WTF?? When I was using the 105 AMAX I didn’t seem to have any issues with spin drift out to 500 yards.
What scope am I using? 16X “Super Sniper”. Yes, I know – I know…. (hanging head in shame). I am still waiting for the PSTs to come in.
I used a torque wrench to properly tighten everything. Scope mount is the new Burris AR mount.
Thanks so much for any input / suggestions.