Team,

Does anyone have any cast bullet loads for .458 Socom? I have some 300 gr Lyman 457130 bullets I’d like to use but I can’t find any data. Does anyone have anything they can share or any data source they can point me to?

Thanks,
Jeff

I've run a Saeco 350gr L-RFN-GC @ 17Bhn in a 16"Satern 5R carbine Bbl/gas w/Superlative adj block & 7.2oz buffer w/Sprinco X hvy(orange) spring for a few years now.

StarLine brass
CCI 350 LPM primer
SBR-SOCOM powder @ 35.0gr
2.190"OAL(.010" jump)
@ 1780fps
shoots 1MOA on a regular basis

Dan,

Thanks for the reply and the data. However, I do not have any of your powder. Any suggestions for powders I have - 2400, 4227, 4198?

Thanks,
Jeff

The Hodgdon site has loads with two of your powders and similar weight bullets. It shows pressure now too so I would go a grain or two less than the start loads and check your results.
Cast and pressures below 28000 psi would be my goal. 4227 is usually a good cast powder. I have no experience in making a gas port work with cast loads though.

Use jacketed bullet data. Readily available.
Now if you are shooting them in an AR, it might fill up the gas port. You will know when and if it does.
If you have a bolt action, then you can go far higher pressure, until you get leading or stripping and they won't shoot.