As you probably know this round was purpose built with shoulder set back for the 300 gr. bullet. A guy that I know that was working with one went up to 91 retumbo, cci250, 300 smk, start lower. I shot about 45, 285 HM and maybe I did not go up enough, but they were not having intial results like the berger for me. I will be shooting monday, and testing some more. I went up once but had scale problems on my old dial a grain, new scale now. I did shoot 87 and 87.5 retumbo, fed 215,300 hyb. gen 1, velocity 2650, and shot 2'' at 400 yard, center mass hit a rock at 825, and my son at 1016. Similar load in 285 shot lower at 1000, but I NEVER took it up hotter, just was not grouping for me, and I had already shot some 1'' @ 400 w/berger -.005 off.Its bear season so IM TRYING TO GET ROLLING.
The Smith that is building the rifle said the 285's would run with the 300 out to about 1200 yards, then the 300 would take over. I will try them all, once I get the rifle. I see a lot of elk at 1200-1400 yards, and want to be able to shoot that far. 400-500 rounds of practice first. I seen my son-in-law hit the end of a 55 gallon barrel, with a cold bore shot, at 1320 yards. He was shooting a .338 Edge.
Does the Retumbo work good in the Norma? I heard that Ramshot Magnum works real well, and it meters well, and it's from Montana. I don't like the RL brands, because of the temperature swing affect it has.
I ran the #'s and that is what lead me to try the 285. Drops where to be the same like you said. I dont think I got the 285 quite up to speed, but it shot lower @ 1000 than the berger, side by side. The berger is revised .818, the hornady .720, the berger carries 200 more energy across the board at all ranges, whats not to like. I put 3 bergers in 1 1/4 today @ 400, third time in last 2 wks. gota go with it. We have a bison gong at 460 and that 300 just rocks that thing, I put eyeballs on itI will try 285's some more because I RAN OUT of berger,back order. Retumbo is a extreme powder, the load I gave you before is from the GM of a gun shop that is in process of building a 20,000 sq. ft. shop. 10 rnds es 5, in my rifle and his, this powder he put 3 in 4'' at 1100 +, that rifle was 338 edge on classifieds few weeks back, had a ABS BARREL ON DEFIANCE.
This cartridge was built around the 300SMK. along with SAAMI reamer. The cartridge doesnt respond well to the usual powders Ramshot magnum will give the best velocity with R-22 second. Both powders were used extensively during testing.
The following powders shot bug holes, but only Ramshot and 22 reached the FPS I wanted. H-1000 was a little light on FPS but extremely accurate.
"Fast is fine accurate is final"