Time to update this thread now that I have a wee bit more data. As some of you know I put together an 18" LR-308 with a lightweight stainless-steel 1-in-10" barrel recently and have been shooting cast bullets through it suppressed. Keeping muzzle pressure low and velocity up has been the focus here with loads and its tough to do both with such a short barrel, but I finally got it licked with 36 grains of RX7 under the MP 30SIL HP @174 grains, gas checked and powder coated, sized .3105" on the bands with the nose riding .301" in my nose-first custom bump die. NO lube of any kind on the bullets. No special case prep, just bumped fired brass .001" in a fl bushing die and squeezed the necks to .307" on the inside, prep with a .309" spud and seat bullet. Very light crimp with Lee roll-crimp die. I didn't turn the necks, never trimmed them, only vld inside chamfered, and didn't weight sort the bullets.
The 5/8" group was fired first from a barrel that had only had one clean dry patch through it since shooting lubed, pc'd cast through it almost a month ago. This is my first HV sub-moa group with oc cast. I got excited and went after my Magnetospeed, which gave me the second group. I might have dropped the low one but didn't call the other so I can't say what happened but 1-1/4" for five at 100 yards still ain't bad, especially with the magnetospeed hanging off the muzzle and pulling the poi down an inch.
Now for the cool part:
Not bad for a 2.5/2.5 air cooled alloy at 14 bhn, from the magazine of a rifle that feeds itself, eh?
Getting closer all the time.