Advice on working to a safe load for .50AE 400grain

[qualcorp]

FWIW: 34.0gr H110 chrono'ed 1400fps with the Rainier plated 300gr flatnose projectiles in my DE50AE.

I was using Rainier (I like) 300gr HP projectile with the A2400 don’t know how fast it was going but it surprised the hell out of me as the first time I put a real round down the bbl, up to that point it was off the shelf Horn and whatever I could get my hands on FTF store bought. In fact I really don’t remember where I came up with using A2400 in the first place.....somehow I thought it was a good idea as I picked it up just for this cal. and is all I've used it for. hmm

[Seismic Sam]

FWIW: 34.0gr H110 chrono'ed 1400fps with the Rainier plated 300gr flatnose projectiles in my DE50AE.

That sounds about right to me, and Ranier and Berry's bullets can be used to a certain velocity in a DE50. Part of the reason for that is that the DE50 has POLYGONAL rifling, so there are no lands to rip up the copper plating and make it separate from the lead. With normal rifling in a Smith 500, around 1400 - 1500 FPS the standard deviation of the velocity will go all to hell, and you will have a spread of 200 - 300 FPS because the plating is coming off the bullet, and when it does that the pressure blows by and the velocity drops a bunch. FWIW, the Ranier bullets hold together longer than the Berry's.

[Swen]

That 24.5 of H110 seems about right at max considering heaviest 454 casull loads with 405gr bullets are at ~24ish of H110. The 454 and 50AE have similar case capacities. One thing to remember with using H110 or 296 is to not use for reduced loads. Those powders have tendencies to have pressure spike issues if reduced too much. So like you said if you have a guy that has used those same bullets and powder combination and is trustworthy, start low and watch your primers. Using LPP over the SRP in the 454 you should be able to see flattening fairly easily and at that point back er' off a bit. With H110 start low (but not too low) and work up as you should do with every cartridge.

ETA: Make sure and get a COAL from that guy to, as seating depth can affect pressures also.

On the OAL issue he did say "maximum" but I will verify what that is as while the true max on the Israeli IMI site and wiki say 1.610 I've read plenty of load data that says 1.600 is true max. I suppose every hundredth matters.
Thanks for the info, will definitely be looking for flattened primers and other signs. I imagine it's more up to me getting the measurements correct as the group he shoots .50AE with all use this load now being they have "truck fulls" of this specific bullet. They even use the same brass and primers so it's definitely a trustworthy source and I understand the importance of that.

[BigDog58]

qualcorp, I have H-110 and if you'll remind me next time you are over I'll give you some to use and test on your 50 ae. I mainly use it for magnum handgun loads, which I don't frequently load. We can take the chrono next time we go shooting and compare the H-110 to your loads with 2400.