i shot my rock river arms .458 socom last weekend, and i'm hooked again... i bought all the factory corbon i could find locally, 2 boxes... 1 was 350 gr hp's and the other 400 gr sp's...... i'l like to load laser cast 405's, anybody have any data to start with???... thanks, jim

Loadswap.com list a couple of different loads.

This site has some spread sheets.

[URL=http://www.mylittlespark.com/ar15/458Socom.html]

I found that the Corbon ammo was pretty hot. The head stamps were so misshapen during ejection that they would not fit in the shell holder to resize them. Also do not waste your money on the Lee dies, they are junk. I ordered some Hornaday dies from Lock, Stock and Barrel. They are still on back order. Let me know how your loading goes!

so far the corbon brass looks good, no marks at all.... what's wrong with the lee dies???... i have them, and have 200 brass on order from midway...

Me too!! I bought an upper in 458 SOCOM and I'm waiting on brass.

Load data are scarce. I contacted the folks at Teppo Jutsu and they sent me some spreadsheets. Most of the data were QuickLoad maximum charges for a long list of powders propelling 300gr and 405gr bullets at a maximum chamber pressure of 35,000 psi. Unfortunately, the COL wasn't provided -- and some of those powders were faster than I'd be comfortable with.

One sheet listed the cartridge developer's pet loads -- but some of those look like they exceed the 35kpsi ceiling.

Reloder 7 seems to be a favored powder. Rifle powders like 4895 and slower seem to leave a lot of unburned powder behind. I was hoping that A 2230 or IMR 3031 would show up in the lists more than once.

Using the 300gr JHP bullets, Reloder 7 seems to be the fastest powder that you can "fill the case with" -- up to 44gr for a compressed charge -- but I see 10% discrepancies in charge and COLs that run from 2" to 2.25" for the same bullet.

I figured that load data for the 50 AE might serve as a starting point but the magnum pistol powders (H110 and W296) only show up in one source for 458 SOCOM; I saw H 110 and W 296 running from 32gr to 40gr with 300gr bullets -- but the COL wasn't reported.

Of the two bullets you mentioned, one appeared in the pet loads. With all the usual cautions, I can tell you that I was told: Remington 300gr JHP over 44gr of Reloder 7 assembled to 2.020"

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jimatcat

Have you used your Lee dies yet?? First off I have a predisposed dislike for Lee dies. On my new .458 SOCOM dies the ID of the dies are rough. They left scratches on the cases.

I was also having a difficult time due to the misshapen brass. I would send you some photos but I threw it all out. Maybe my chamber is a little tight, but Corbon ammo is known to be a little on the hot side. My rifle is a RRA upper as well.

I have 500 rounds of brass but I have not loaded any of it yet... I am waiting on my Hornaday dies.

Another good place to get reloading info is on www.458socomforums.com go to the reloading section and look at what is posted there.

Good luck. I will let you know how my loading goes once I get it going.