Duplicating a "factory" load

[Jim]

I've spent the last hour or so reading up on the Garrett 540 grain "Hammerhead" ammo. I don't see a problem having a mold made to duplicate the bullet. Not knowing exactly what the lube groove/band pattern is, I would imagine a couple of our resident bullet designers could solve that.

As for powder choice/charge, now that's another question. Anybody got any ideas? How 'bout it, Felix? You're a whiz-bang at this kinda' stuff. Wanna take a shot at it?

http://www.garrettcartridges.com/products.asp

[felix]

Best stab at it, Jim, would be anything between 3031 and 4320, but NOT a double base powder therein. My preference for a start would be 4064 with that heavy projectile at that velocity attempted. ... felix

[Jim]

Felix,
I'm not nearly as well versed on powders as you are. Any ideas for a starting load? I have a chrony to work up with.

[felix]

Jim, start with 40 grains, 1 shot, RP standard LR. No need for chrono just yet. Measure case diameter with caliper up against the rim before and after the shot. Dry brush before the shot, and take a look through the barrel afterwards. Pay attention to recoil force. Report all info back here. ... felix

[Jim]

Umm, well, Felix, first I gotta get a mold!

[felix]

If no mold yet, I'd strongly consider the consequence of recoil, and choose accordingly. Increasing velocity with those heavy slugs to realize 35K CUP is not child's play, which means you will not realize accuracy unless you are truly an expert with elephant (buffalo) guns. ... felix

[Jim]

Well, truth is I can't find a 540 gr. mold. Lee makes a round nose flat point GC in 500 grain. I've shot plenty of those in round nose and spitzer point. I might just go with the RNFP G/C.