Optimum loads for 458 socom

[adcoch1]

Hello everyone, I finally shot my 458 socom for the first time the other day and had a few minor issues to discuss. The first was a minor feed issue from using a bone stock pmag, which I will mod before trying again, but the big question I have is about loads.

I ran 10 rounds of IMR4198 at 35 grns with a hornady ftx 325 grn bullet at the crimp groove, 2.015 coal if I remember correctly. This was from a load list found online, can't remember from who ATM, will look later. The max load was 36.6 grn I think.

So these loads will cycle the action just barely, getting about 50/50 on bolt lock back. Another sight stated a max load of 38+ grs of the IMR, so maybe I am just too lightly loaded?

Also, is imr4198 a decent powder for the socom? I started there because I have some, I also have h110 and some 4227 along with others that will probably work. I'm asking mostly for discussion sake, and to avoid burning through a ton of bullets just finding a functional starting load.

 

[Blue68f100]

With IMR 4198 the load data I have, has a range of 35.0-38.8gr. So your on the light side. I found the sweet spot for my gun to 38.5gr with the 325gr FTX. My preferred powder for the 458 SOCOM is the W296/H110, load range of 27.6-31.1gr. The sweet spot for my gun was 29.7 gr a OAL of 2.140". This give me a velocity of ~1700fps (1672 fps at 15'). When I started loading this round (2015) data was very sparse and all over the map. So start load and work up looking for over pressure signs. I had Over Pressure signs show up at 30.0gr in my gun. I had good results with A1680 and RL-7 too. All using CCI 350 primers.

 

[jmorris]

I and another H110/W296 fan for supers, faster powders like HS-6 for subs.

 

[adcoch1]

I plan on h110 loads in the future, maybe I'll just head there now. I don't remember why I wanted to start with the IMR powder when I planned this project a year ago, but now I have two uppers (one a pistol the other a dissipator carbine) and want to start running them.
It's good to hear I am just having starting load issues, it acted almost identical to my first 300 blk starting loads. Light recoil and about three to four foot ejection of the brass.

I think I will go try some h110 loads, but let's keep the discussion going if anyone has any good insights.

I also have a box of 350 grn berrys plated bullets for the 45-70 that I plan to try out. Not sure if I'll go as big as the 500 grn stuff but you never know...

 

[Blue68f100]

Most don't go over the 405gr unless there shooting subsonic.

The IMR 4198 works fine you just need to bump your charge up.

 

[GarrettJ]

What brand barrels? Carbine length gas system? Pistol length?

I started at 35.0 gr. of H4198 with a 350 gr. bullet and worked downward from there. This is with a 16” barrel. The 35 gr. load ran fine as-is. Somewhere below that I need to have a suppressor in place to get it to run. But it runs subsonic that way, so I’m good with it.

For supers I switched to Lil Gun, which I’ve gotten up to 1650 fps without any pressure signs. But I’m not trying to go as high as possible. A 350 gr. soft point at that velocity will get the job done on anything I need it to.

Oh, and try some Lancer mags. They have worked for me with no mods necessary.

 

[adcoch1]

I am going to pick up a few lancer mags.

The barrels are an 8" pistol gas system with adjustable gas block, and a 16" carbine gas system.

I want a few loads that run in both, and for the moment I am looking for supersonic. I will get into subsonic loads later, for right now I want plinkers (for general use and deer hunting) and bear protection ammo.

 

[Blue68f100]

Lancer mags are good, I have a few of them I use with the SOCOM.

 

[adcoch1]

Update: decided to run a few rounds tonight since I finished my dissipator carbine upper. Ran the Berry's 350 grn to the crimp groove over 37.0 grn of IMR 4198. Five through the pistol and five through the dissipator. Wow! Recoil like I expected from a 45-70 class cartridge, LOTS of fun in the pistol and zero feed problems using a c-products mag. The dissipator is a pussycat! It kicks a bit, but it is great to shoot. I think I found my plinking load!

 

[jmorris]

The SOCOM can get pretty close to factory “trap door” loads but falls a good bit behind “marlin” or (#1) 45-70.

If your just plinking you might try HS-6 you’ll use half the powder and it makes less noise, if you are shooting suppressed.

Makes it easy to hear the 300 yard steel, my buddy missed the 3rd shot.

 

[adcoch1]

Not shooting this one suppressed yet. Just using it as a thumper hunting rifle/camp gun. It sure is fun though, shooting an ar15 that has some kick. I would like to get a 45 suppressor soon, but a 22 can is next...

 

[jeeptim]

I have been shooting the Socom for a while now...
Feeding can be troublesome.
I now cast and powder coat my own with really good results.
I also use the Hornady 325gr but costly.
I started with imr 4227 but was getting unburnt powder lil gun has been my go to powder. I also use pmags trim the lips a lil bit. 4rnds in a 20 rnd 5.56 mag seem best and 6 in a 30 rnd otherwise I notice to much drag on the bolt.
The best thing I got for reloading the Socom is the Lyman ammo checker.

 

[alfsauve]

I only have about 50 rounds through mine. Once a got a properly ported upper and put flat followers in my mag it runs well. LilGun is what I'm using under a 325gr bullet. Seemed that was the most popular choice from other forums.

 

[jeeptim]

Went to the range Saturday banged our 100 rounds at the tin can range 50 yd not much left in the way of tin cans.
Shoulder sure feels it.

 

[Blue68f100]

The reason I run a GL-Shock absorbing stock on SOCOM, tames the recoil. This stock has a shock absorbing spring it. Make it like a big push vs hammer hit. That or run a 1" Limbsaver.