I did a bit of experimenting with my two 358 MGP ARs, one is a 12 twist and the other is a 20 twist I started with the 200g RCBS FP Silhouette bullet and 1680, I have the GC and PB versions of the mold. I S&B the bullets, removing them with the bent needle nose pliers, picking them up by the ogive, sitting them nose down in a up side down hardware cloth box, 1/4” expanded with a round punch, so the bearing surface and base are not molested. I use auto chrome black, used for blacking out a vehicle. Bake at 400 for 20 minutes, cool. Re coat, bake and cool. Size using case lube to .358 my groove diameter. With no gas checks at all, I get 2,500 fps at .4 inches at 100, and no residue or leading in the ARs.
I had put the load together to fire form 60 rounds of brass and realized I had one hole. So swung off to the side, .4” for 3 at 100.
That was a max load for he MGP, I am building a 35 Whelen, 1-14, on a 700 Action. I want to see what the Whelen’s bigger case will do wih he same bullet.