.458 Socom Surprising (to me) numbers

[blackpowder man]

So I’m not new here and have spent way more time reading than posting. I have shot thousands of cast boolits from a couple dozen calibers and have yet to break out the chronograph and check the speed on my loads. I’ve had the chrony for probably 10 years or more and for whatever reason I do my research through manuals and often here and work for accuracy first and max power second. I’ve hot rodded my share of loads, usually with jacketed bullets, and i do love big bores! The great thing about big bores is they don’t have to be squeezed for every last bit of power to be effective.

This leads me to my .458 Socom. It is my semi auto buffalo rifle and I’ve been really enjoying it for some time. I had a .450 Bushmaster for a couple of years and it was pretty cool, but I like the Socom better. I’ve been shooting Sierra 300 grain hollow points, 350 grain Midway tmj’s, and Lee 459-500-2r’s through it for awhile now. With a little bit of extra time I decided to get into this powder coating game hoping to use my other.45-70 molds for the Socom. I pc’ed some Lee 457-340s and some NOE 460-340 hollow points. I tried the Lee 340s last week with Lil Gun and had some promising groups using 24.5-26.5 grains. I was thinking the lower level loads may be in the 1450-1500 fps range and wanted to know for sure. So, I dug out the chrony and shot only a couple of shots using a number of loads to see where I was with the speed. Some of these were a real surprise and some not as much. I thought my 500 grain Lee load over 25.5 grains og RL 7 was in the 1100 fps range. Turns out I was wrong. I need to go back and shoot more rounds to check deviation because some of the spreads are pretty bad.

The results:
Lee 500 lubed with lee liquid alox.
RL 7 25.5 grains
1. 1450 fps
2. 1447 fps
Speer 300 Hollow Point
IMR 4227 32 grains
1. 1701 fps
2. Forgot to write it down
Lee 457-340-rf pc’ed
IMR4227 32 grains
1. 1655 fps
2. 1704 fps
Lee .457-340 pc’ed
Lil Gun 24.5 grains
1. 1585 fps
2. 1741 fps
Lee 457-340
Lil Gun 25.5 grains
1. 1666 fps
2. 1665 fps
NOE 460-340 HP
Lil Gun 24.5
1. Forgot to write it down
2. 1638 fps
Midway 350 TMJ
IMR 4227 32 grains
1. 1577
2. 1561
3. 1564
4. 1564
Black Butterfly 350 TMJ factory
1. 1697
2. 1559

I’ve read all or almost all of the info on the .458 Socom here and maybe this will be helpful to someone else. I’d love to hear from others loading the .458 Socom about what is working for them. I would be happy with a 340 flat nose and hollow point in the 1650-1750 range and I’m going to pc some Lee 500s and see if they hold the accuracy they do with lube in the 1450-1500 fps range. I’ll post updates as I learn more.

[djryan13]

What Chrono were you using? I recall once running some Subs with my Labradar that were shooting too fast. I realized I had it set on rifle when it should be set on pistol.

All loads cycle?

[blackpowder man]

It’s a Beta Chrony made by Shooting Chrony. All loads cycle. I’ve been shooting the 4227 and RL 7 loads for awhile. I had the chrony 10 feet away or so and got a reading every shot. It seems like so much of the “data” I see is quickload data. And honestly that is better than no data. I’m going to post some more as I get a chance if only to possibly help someone else. It would be nice if they’d saami spec the cartridge, but I guess I get the reasons. I shot the .300 whisper before it got spec’d to the blackout and the .22 tcm when it first came out and it was a similar game. That .375 Socom looks interesting too... already debating how a 300+ grain .38-55 bpcr boolit would work.

[dkf]

The .458socom was submitted to SAAMI by the creators around 5 or 6 years ago. The reason it has not been SAAMI approved is all on SAAMI and their members. Many of the members are in the gun business and only want their own and their buddies cartridges to get approval.

[blackpowder man]

I had not read or heard that before. Interesting, everything is always political.

[dkf]

Yep, political good ole boys club. The .458socom is a competitor to the .450 Bushmaster from Remington. Guess whom is a SAMMI member, thats right Remington. Wilson Combat got the .300hamr SAAMI approved in months, a cartridge with next to no following, ammo or guns chambered in it. Of course they had Western Powders, Starline Brass and Sig Sauer get behind it to ge tit approved. Doesn't matter how good something or how good you are at your work, it boils down to who you know.

I guess it really doesn't matter. The .458socom has dominated over the .450bushmaster in number of guns made for it, variety of ammo made for it, variety of bullets made for it, barrels made for it, etc. If certain states would not have ammo regulations that favor the .450 over the .458, the .450 likely would not even be as popular as it is.

FYI you might want to try the Speer 300gr JHP bullets too. They are bonded and a lot cheaper than the Sierras and are even cheaper than the Hornadys.

[Patricklaw]

A quick glance at my log book (online) this morning, mirrors your expectation about "500 grain Lee load over 25.5 grains og [sic. ] RL 7 was in the 1100 fps range" I'll look into this further when I get home this evening.

[blackpowder man]

I had a 450 Bushmaster made by Bushmaster and it was accurate and shot well. I like my .458 a lot better. The upper is a factory Wilson Combat with the 1-14” twist. Too bad they didn’t push the 458 too. At least not successfully anyways.
The 300 grain hollowpoints I’ve been using are made by Speer. $17.99 per 50 when they are on sale at Midway. If I get these pc’ed cast boolits to shoot like I want I may use them exclusively.

[DDriller]

The Remington 300 gr HP is the cheapest I have found but hard to find. Have not shot any cast bullets through mine. My normal bullet is a 300 gr swaged using dies from BT Sniper.

[Intel6]

DDriller, I own BT's original set of .458" swaging dies he made for himself to make bullets for my SOCOM.

Below is a pic of the 300 gr. big mouth HP's made out of .45 ACP brass





Below is a 405 gr. JHP made out of cut down 7.62x51 cases





And to the OP, I also shoot quite a bit of cast bullets out of my SOCOM also.


Below are my two most used bullets in the SOCOM. The NOE 354 HTC and the NOE 500 gr. Spire point.






Below are the two heavy NOE MOAB bullets. The mould with flat pins makes a 600 gr. solid and with the deep HP in installed makes a 570 gr. HP.

[blackpowder man]

I looked at the swage die set ups some years ago. You inspired me to look again and as incredibly awesome as it would be to make my own jacketed bullets it is still well outside my toy budget. Looks like he makes a nice set up.
Are those bullets left with the old rim, primer, and headstamp on when loaded and fired. If so that is very interesting.
I’ve looked at the 600 grain molds and the no lube groove pc molds and may have to try one. Have you shot the 600s at any longer distance?

[DDriller]

Intel6 it is your fault I bought the die set. My 300 gr bullets look a lot like yours. Getting ready to Hi-TeK some bullets then run them though the die to see what it does.

[Intel6]

Are those bullets left with the old rim, primer, and headstamp on when loaded and fired. If so that is very interesting.
I’ve looked at the 600 grain molds and the no lube groove pc molds and may have to try one. Have you shot the 600s at any longer distance?

Yes, those pics are of a ready to load bullet and a loaded bullet. You get interesting results when you recover the fired bullets. The first pic below you see some bases after the bullets were fired at steel plates at shorter distances. In the second pic you can see what happens when the same types of bullets are fired at slower velocities at steel and the brass "jacket" doesn't break off, you get brass "flowers."

[Intel6]

Intel6 it is your fault I bought the die set. My 300 gr bullets look a lot like yours. Getting ready to Hi-TeK some bullets then run them though the die to see what it does.

Ha Ha! I am guilty. I ran some of the PC'd NOE 354 HTC bullets into the dies and came out with a nice HP'd version with a slightly different profile. I don't have that mould in HP version so it was nice to see I could HP them if needed.