I was sighting in my Thompson Compass 308 bolt action rifle yesterday.
I had purchased 2 boxes of ammo on the recommendation of the store clerk at a local sports shop.
The 1st was Federal Power Shok in 180 grains, the 2nd Federal Premium Vital Shok in 180 grains. The clerk said he uses the Vital Shok when he hunts and that the Power Shok is good for sighting in. So I took his advice. Mistake.
I got the rifle sighted in @ 100 yards with the Power Shok, then switched to the Vital Shok… I shot a group of 3 shots, nearly on top of each other, 4 inches down and 4 inches to the right. I shot some of the Power Shok, near the bullseye, Not touching like the Vital Shok, but in the center. I tried Vital Shok again, 4 inches low and right..
I had some HSM 130 grain ammo, I tried that to compare. Near the bullseye.
Seems all ammo is not the same, even from the same manufacturer and the same grain.
I tried 200 yards with the HSM ammo, 2 inches high.. Now I just need to get more Power Shok and I am all set for hunting.
Links to the ammo I was testing: