jetinteriorguy
I have a Savage 12 LRP and a 10T-SR in 6.5 Creedmoor. Both rifles are at the top of my average of all groups accuracy list. They are insanely accurate and a joy to shoot.
I have really good target scopes on both of them. It pays to have a high power target scope with a thin reticle and a target dot so you can aim 'small' if you want to shoot small. With really accurate rifles like these, having a very precise aim point makes a big difference. You quickly learn that the 'nut behind the trigger' is the only thing keeping you from having really small groups every time.
You made a good choice on powder - IMR4350 has given me the best results by a considerable margin. IMR4064 is second and N150 was third.
My 12 LRP likes Sierra 142 gr SMKs #1742, 140 gr Berger Match # 26401, 140 gr Hornady ELD Match #26331 bullets the best. It also shot 140 gr Berger Long Range #26409 and 140 gr Hybrid # 26414 pretty well. The Hornady 143 gr ELD-X #2635, 123 SMK # 1427, and 140 gr SMK #1740 didn't shoot all that great.
The 10T-SR also likes Sierra 142 SMKs but it shot best with Hornady 143 ELD-X.
I have more Hornady Match, and Bergers as well as 147 grain Hornady Match on order.
Lapua brass with the small rifle primers out performs Norma and Hornady brass with the large rifle primers simply because the LRP brass primer pockets wore out in 4 reloadings and the Lapua SRP primer pockets are still tight after 5.