Originally Posted by Rockfish Dave
Very impressive build, video and muzzle brakes!
You kind of have me scratching my head on my build. I just finalized my 338 Lapua based wildcat reamer to work with 350 gr SMK's with a CIP Lapua Mag Magazine, but I am tempted to switch to a single shot for longer freebore and hence greater case capacity and lower case pressures.
Mind sharing your thoughts?
I have built a couple of 375 Terminators, 375 Lapua Improved, on the big Barnard P-Chey actions with 32" Bartlein gain twist barrels, they go exceptionally well with the Cutting Edge projectiles not far behind the 375 Cheytac with only 111-114 grains of powder, but as the projectiles are so long mag length rounds just won't work.
I didn't do much at all with the SMK in those rifles as the 7.8 & 8 exit twists are a little hard on the jackets.
I also built a 375 Rum imp on a Rem 700 with a 30" 1-11.5 barrel for S&Gs.
It shot the 350 SMK at approx 2825fps & 330 CEs approx 2925fps with under 110 grains of powder, it was long throated & once again no way it would mag feed.
The Aussies are building a few over there, they call them the 375 Sledgehammer, they should have info on mag feeding etc, I think one was going in a DTA
One thing to consider is the recoil is pretty brisk
The small efficient cases are a bit of a problem because you can build a light weight rifle that will push a fairly big projectile reasonably fast with relatively small amounts of gas velocity & volume so the muzzle brake has very little to work with.
I re-chambered a light 700 338 Win mag to 338 Edge then even bigger again on the same short barrel, the difference between the Edge & its bigger cousin was 300 fps & around 25 grains of powder.
I didn't test it but recoil appeared to stay the same, it certainly didn't increase noticeably, the brake was loving it with all that gas pressure, volume & velocity