43.5grs of H4350 using a 123gr Lapua bullet has shot really well with 4 different rifles we have shot this load in. Varget works well too. You just need to see what your gun likes.
One of my 260s loves Varget the other one likes anything. One shoots the RL17 into .3s & .4s the other one won't harldy put the same load into an inch for only 3 shots!! Guns are like women they are all different!!
I can't speak to gas guns, but I worked up about 500+ rounds using AA-4350 and 140 AMAX/142 SMKs for a buddy's Surgeon/Rock/AICS and if you can't find the Hodgdon verson, get the AA as it's a dead ringer.
I don't know if you need to try the heavies, but both seemed to shoot well out of his bolty.
100 gr Nosler Ballistic Tip moly coated # 26100 bullet moly coated , 45.0 gr canister IMR4895, 2.940" over all length, almost no insertion of the bullet into the neck, due to the short bullet and long throat. Quickload prediction 61,328 psi 3261 fps for 22" barrel chronographs as 3,236 fps
This is the most accurate I have found in my rifle.
I am going to try the lapua 139 with h4350, and the 123 lapua with re 15. Do these combos sound good, and does anyone have any starting loads? I am going to be shooting it out of my new gap ar 10 with a bartlein 22 inch barrel with a 1-8.5 twist.