458 SOCOM cast and load info

[Snagman]

I'm purchasing a .458 SOCOM upper to put on top of one of my AR platforms and plan to cast and reload my rounds to keep the cost down. I was looking at the LEE molds but most of them are .457 diameter and I was thinking that I need a .459 diameter to properly work. Is this correct or will the .457 diameter bullets work OK? I've also looked at the RCBS molds but some of their reviews aren't all that good so I was wondering if anyone has a mold, bullet, and recipe that works well in their AR and they would like to share?
Thanks for your help

 

[FrankenMauser]

You generally want 0.001" to 0.002" larger bullet diameter than groove diameter. But, in the case of .458 SOCOM...
Bullet diameter will depend upon who made the barrel.

Tromix barrels are very precise. Most people can't chamber a cartridge loaded with .459" bullets.
Rock River barrels are also pretty tight. Some people can get .459" bullets in there, but not all.

Places with chambers cut by the PTG reamer (like BCA, Radical, Davidson, and more), will usually swallow a cartridge with a .459" or .460" bullet without issue. ...But it's best to avoid those barrels for other reasons.


What type of bullet are you looking for?
NOE offers a few things that work for .458 SOCOM, and a few things designed specifically for the .458 SOCOM.

 

[44 AMP]

Cast bullets and gas operated firearms seldom "play well together".

There is an added complication beyond the usual "right alloy, right lube, right bullet to bore fit. etc."

And that is the gas system. Lead, bullet lube, and powder residue together can make a very effective plug in your gas system.

Can, not "always will" but can. If the firearm does not have a gas system that is easily accessible for cleaning (and that includes the barrel gas port) the wrong combination of factors can leave with quite the chore to fix.

I don't consider the AR gas system to be easily accessible. Disassembly, cleaning and reassembly of the AR gas system is not a chore you want to have to do on any kind of a frequent basis, nor is it good for the rifle.