458 SOCOM Loads

[RugerFan]

I recently aquired a RRA AR-15 in 458 SOCOM. My intent is to use it for primarily sub-sonic loads. I currently have the following molds: RCBS 45-300-FN, 45-405-FN and Lyman 457483 (385 gn). I will probably obtain a 500 grain or heavier mold as well.

Anyone have any sub-sonic loading data? A forum search has yielded mainly super sonic load data.

[dkf]

There is data floating around at the .458 socom forum. Several use the 525gr piledriver from beartooth. Takes it while to get membership approved over there though. I don't know if you will be able to stay under 1100fps and get the rifle to cycle on the lighter bullets you currently have molds of without opening up the gas port. Best to just go heavier.

Some 500gr jacketed data here but I don't know if it subsonic or supersonic.
http://teppojutsu.com/downloads/458_...ading_data.pdf
http://teppojutsu.com/downloads/458_..._reloading.pdf

[RugerFan]

Ya, I've got the Teppojutsu stuff. Didn't see any cast sub data. The .458 SOCOM forum registration is currently "disabled." Weird.

[dkf]

That site has the weirdest registration of any site I came across. From my understanding it is that way because of hacking and spammers opening accounts.

I usually just go off jacketed data, reduce the load some for cast and work it up. The threads in the links below may help you some.
http://458socomforums.com/index.php?topic=870.0
http://458socomforums.com/index.php?topic=3061.0

[RugerFan]

That site has the weirdest registration of any site I came across. From my understanding it is that way because of hacking and spammers opening accounts.

I usually just go off jacketed data, reduce the load some for cast and work it up. The threads in the links below may help you some.
http://458socomforums.com/index.php?topic=870.0
http://458socomforums.com/index.php?topic=3061.0

Awesome, thanks for the links!

[wlc]

RugerFan please post with your results and experience with the new rifle. What can are you running?

[RugerFan]

RugerFan please post with your results and experience with the new rifle. What can are you running?

Oh I definitely will. I don't have a can yet, but one will be in my stable before long. I'm hoping the Donald will change the NFA rules for the better soon. Either way I won't be doing much shooting until spring break up as its a bit chilly here through the winter. Where are you located?

[wlc]

I'm in the Valley. Between Wasilla and Big Lake. And yes, unless we get some warmer temps I won't be doing to much in the way of shooting either. Probably do some loading as soon as I get through with a few "honey do" shop projects.

[pakmc]

Trail boss in .458! I just shot 14.5gr's of TB behind a berrys 350 gr. bullet in an AR-15 upper. the recoil was a little less than my load of 26.5 gr' of H-110. the TB would not work the action of the upper, while the 26.5 gr's of H-110 pulled five rounds out of the mag.(a 30 round 5.56 mag.) and they where quite accurate at 50 yards in rapid fire.

[Patricklaw]

+1 on the 458 SOCOM forum.

I too have an RRA upper. It seems to really like the Lee 459-500-3R powder coated and set on top of 26.5 grains of R7 or 25.5 grains of 4198. I'm guessing they run about 1,100 feet per second but I've never shot them over my Chrony.

https://leeprecision.com/mold-dc-459-500-3r.html
https://www.midwayusa.com/product/10...ted-round-nose

[RugerFan]

Since I began this thread 2 years ago, I have temporarily shelved the Sub-sonic load evolution. The Hearing Protection Act doesn't seem to be any closer to happening, so my silencer purchase has been put off for the time being. However, I wanted to get some kind of load development done for next years bear hunting.

In addition to the RCBS 45-300-FN and 45-405-FN mentioned in post #1, I have also obtained the NOE 460-530-FN and RCBS 45-500-FN molds. However, I must have a tight throat or something because when crimped in the crimp groove, the rounds don't want to chamber. The front bands are engaging the lands early.

Before the cold and snow took over, I began loading the RCBS 45-300-FN seated just deep enough to chamber. 31 grains of IMR 4227 proved very accurate at 30 yards with a 2-7x Leupold scope. The reason for shooting so close is because that's the distance of my ground blind to bear bait. I'll try stretching out the distance (and chronographing) in the spring.

[Petander]

However, I must have a tight throat or something because when crimped in the crimp groove, the rounds don't want to chamber. The front bands are engaging the lands early.

The crimp groove may be located for 45-70 /458 -length. I can not use the groove in heavy FN:s, the nose will not fit.

Try seating some dummy rounds deeper,past the groove. Adjust your load,it will rise pressures. 458S does not necessarily need a crimp if neck tension is good,at least Starline brass has tons of tension especially when new.

It's also very easy to crimp too much and bulge the shoulder just a little,enough to prevent chambering.

Here is how my 480 grainer cycles in a Tromix:

Attachment 232317

[Gtek]

My limited experience witnessed a very easy and fast ride into over pressure signs on primers. Very small tweaks for me when exploring!

[RugerFan]

The crimp groove may be located for 45-70 /458 -length. I can not use the groove in heavy FN:s, the nose will not fit.

Try seating some dummy rounds deeper,past the groove. Adjust your load,it will rise pressures. 458S does not necessarily need a crimp if neck tension is good,at least Starline brass has tons of tension especially when new.

It's also very easy to crimp too much and bulge the shoulder just a little,enough to prevent chambering.

Here is how my 480 grainer cycles in a Tromix:

Attachment 232317

Good info!


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[RugerFan]

My limited experience witnessed a very easy and fast ride into over pressure signs on primers. Very small tweaks for me when exploring!

Good point. Duly noted.


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[the_ursus]

I’ve been shooting the RCBS 45-300 with my Tromix SOCOM with great success. Starline brass, CCI LP primers and 40gr Reloader 7. 2” groups at 100 yds. Haven’t checked it on the chronograph yet but it’s a real thumper.

[RugerFan]

I started back at the range about 2 weeks ago. The snow is mostly gone now.



The RCBS 45-300 with IMR 4227 is clearly a winner. Inching the charge up a tad I'm getting 1,683 FPS. I have a Leupold VX-2 2-7x sighted in for 50 yards (Max distance I expect to shoot over a bait) and am getting great accuracy. Next time I'm at the range I'll try to remember a target pic.

Since the pic above, I have changed out the RRA mount in favor of a Leupold mount that allows some space on the flat top where I have installed a 45 degree reflex sight. The purpose of which is for quick acquisition in a too-close encounter.

[blackpowder man]

How much did you bump up the IMR 4227 for that 1683 fps? That seems like a good combination of power vs recoil.