Had a chance to hit the range yesterday for some practice with the Tikka 6.5 CM, sight in a new to me Christensen Arms AR10 .308, Spikes 6.8 and Seekins .556. I've never shot groups at 300 so gave it a try with the Tikka and CA.
Fired 5 shots quickly on the Tikka with Hornady factory Match 140 AMAX and then 5 more with custom loads with 140 AMAX. I like the vertical with the custom loads and jerked the 3rd shot right. Next time will wait 2 mins between shots to let the barrel cool. Hit steel plates consistently and made 8 of 10 shots at 800.
The CA10 308 shot very well for a lightish AR10 and made 3 of 5 hits at 800.
Took the AR15 .556 with SWFA 1-6 from 300 to 700 (Hornady Match 75 gr OTM) and made consistent hits at 600 but very few at 700.
Took the Spikes AR15 6.8 with SWFA 1-4 (Hornady 120 SST) out to 500 but could not connect at 600.
Heck of a fun day!