Nice shooting!! Amazing how much energy those 300g SMK"s deliver on target. I had the same problem with my gong set up at 1000 yards as well. My 1st hit with the EDGE just plain ripped it right off the stand.
The first ime that I chronographed my load the Ohler 35 gave me a velocity of 2820 FPS and my drops were a bit low. I had this 4X6 under the front of the target frame inorder to level it up.
These 3 went into about 3" at 975 yards
The day was very a very bright sunny day that I recorded 2820 FPS, I re-chrono'ed the next time on an overcast day and came up with 2791 FPS and now all is good
The 300 Gr. SMK with H-4831 is also a shooter. I shot a couple of 1.00" 5 shot groups @ 200 yds the other day to test the load. So, that is .5 MOA @ 100 yards. According to my external balistic program the 300 gr. has more drop @ 1,000 than the 250 Gr. by about 18". However, the energy is still there. I'm going to try it @ 1,000 if the wind ever stops blowing here in our valley. I'm wanting at least 1 MOA at 1,000 yards under ideal conditions.
I'm pulling the Surefire muzzel break off my Surgeon 338 Lapua and replacing it with a Holland break. The Surefire is okay..but it is set up to accomidate a Surefire Supressor ($1,800.00). I have a different supressor ordered ($650.00) ..waiting on the ATF paperwork to be completed. The Hollan break is a bit lighter and will unscrew when I want to screw the supressor on the Lapua.
I'm going to try the H-1000 with the 300 Gr SMK soon. I like the H-1000 powder in my 260 Rem...also in a Surgeon rifle..the best groups is with a 140 Gr. Berger VLD Moly coated bullet and 48 gr. of H-1000, .166" 5 shot group. It is very consistance "Bug Hole" groups.