Do we have any 458 SOCOM guys/gals loading or shooting these?



Doing a little info recon and study for this one...Data is sparace and required lots of searching and even pulled in favors from others to help.  Here is what I have learned so far by working on this project;

Best dies for the handloading of this cartridge is the Redding set. Redding #: 80444  The shell holder for 45ACP, 308 or 30'06 will work.  Using the LEE for 45ACP with the die in contact with the bottom of the sizer is working.
Cases from Star Line 1.5740" after sizing.  Some trim theirs to 1.5655".  Be sure to debur the inside of the cae mouth, makes for easier bullet seating.
Imperial Case Sizing Wax is your friend as there is a lot of surface area to this casing and it is easy to clean after the sizing process.
2.2600" is the limit of the magazines for the AR but many are holding the COAL to 2.2000"
There are a wide variety of bullets in the .458 Diameter but understand there are some which are just too long for this cartridge, one such example is the Barnes .458 #30622 500gr TSX FB at 1.6440" it is longer than the casing...

As I obtain more knowledge as I work with the cartridge I will update more info.

Shadow - I've been tinkering around with the .458 SOCOM for the last couple years. I'm running a Dillion 650 progressive as well as an RCBS single stage loader for some match ammo for a build I did using a finicky KAK Industries upper. While I've loaded 4-500 of these, I've have never sent any past my chrono.....I know,..sad huh. Hoping to do some graphing this summer when things slow down a little.

I've loaded the following so far:
All with Hogdon Lil gun powder with 28-30 gr
Barnes  TSX Flat Base HP /  Tripple Shock  # 45814  /  300 GR
Barnes TTSX Boattail Tripple Shock  # 45872  / 300 GR
Hornady  300 GR HP # 4500
Hornady  325 GR FTX # 45015



If you'd like the reload spec sheets I have been loading from, send me an email and I'll scan them and email to you. mike@ccintl.net

Thanks for your offer Mike...this will help out.
My nephew is wanting to start handloading and I'm gathering as much data as I can to teach him the ropes.
He supplied me with the 3 Underwood offerings that were documented in the Pull-Down section.
Thanks!

I loaded a batch for a friend a couple of years ago and don't have the data in front of me. I know I used H-110 and 300gr Sierra and Hornady bullets.

Well I have researched just about everything I could find on the .458 SOCOM and unveiled some workable and useful data.
Even managed to enlist the help of Sean to crunch some Quickload info as well.

These are some of the loads we are putting together

HORNADY 500 gr 458 SOCOM 45 Cal .458 500 gr InterLock® RN
STAR LINE BRASS length 1.5740"  Base Dia. 0.5390"
Hodgdon Lil'Gun 20.0 Grains
Bullet length 1.3365"  with 0.6260" outside 0.7105" inside case
CCI 350 Large Pistol Primers
COAL 2.2000"
Velocity 1050 fps (SUBSONIC) with  8" barrel

QuickLoad program shows;
8" BBL, Hor 500gr RN #4504
Lil Gun 20.0gr = 1042 fps @ OAL 2.200" = 25,211 PSI
Lil Gun- 20.5gr = 1086 fps @ OAL= 2.200"  = 28,105 PSI
Lil Gun- 21.0gr = 1130 fps @ OAL= 2.200" = 31,311 PSI
Lil Gun- 21.5gr = 1152 fps @ OAL = 2.200" = 33.041 PSI

Sierra 300 grain .458 JHP 458 SOCOM
STAR LINE BRASS length 1.5740"  Base Dia. 0.5390"
Hodgdon Lil'Gun  28.5 grains
CCI 350 Large Pistol Primers
Bullet length 0.7825"  with 0.3425"-0.3500" inside
HP depth 0.1925"
COAL 2.0140"
Estimated Velocity 1700 fps

Barnes 250 grain TSX FN FB
STAR LINE BRASS length 1.5740"  Base Dia. 0.5390"
Hodgdon Lil'Gun  30.2 grains
CCI 350 Large Pistol Primers
Bullet length 0.917"  with 0.5435 outside and 0.3735" inside
HP depth 0.5115"
COAL 2.1175"
Estimated Velocity 1925 fps

HORNADY 250 gr 458 SOCOM 45 Cal .458 250 GR MonoFlex
STAR LINE BRASS length 1.5740"  Base Dia. 0.5390"
Hodgdon Lil'Gun  grains  30.2 grains
CCI 350 Large Pistol Primers
Bullet length 1.0890"  with 0.6260" outside and 0.4630" inside
COAL 2.200"
Estimated Velocity 1925 fps

I would be curious how LeverRevolution would do as it seems to work well in cartridges of this bulk. Since a .458SOCOM is "essentially" a short 45-70, it would be interesting.

The working pressure for the .458 SOCOM is only 35,000 PSI.
One reason for lack of LEVERevolution data is it may not be listed in the QuickLoads Program, so NO data has been shown in the info I have reviewed so far.

Sean did run some numbers using IMR 3013 which showed low pressures with the 500 grain Hornady RN in one QL scenario, but these AR's can be funny and the bolt may not lock back fully if enough energy is transferred thru the gas system and buffer systems being used.  This showed 500 gr Hornady using 31.0gr of IMR 3031 = 1230 fps at 25,579 PSI , this is a 104% case fill load.  This is difficult to know whether the numbers will be accurate.  Therefore workups and testing would be needed.

Much of the QL data is shown here in PDF files; http://www.teppojutsu.com/458.htm

Can you load a 500gr projectile and fit it in the mag?

IIRC, I was with 10mmMike and he cast some but they wouldn't fit.

The HORNADY 500 gr RN 458 SOCOM 45 Cal .458 InterLock® RN does work, but the COAL need to be 2.2000" some load to 2.2400" but they may be too long for some magazines and feed reliably with the big round nose.

Put these together based on data and testing others mentioned had work for them...Some had gone higher, but mentioned the saw imprinting on their headstamps at 30.5 and upward...  They were seated to depth without crimp and the final crimped in separate step to finish.   

I looked at the 458 SOCOM but decided to go with the straight cased 450 Bushmaster instead. The 450 BM uses the same bullets as the SOCOM.
Both rounds make great deer or black bear rifle on the AR platform.

Good huntin' everybody.

1/23/17 Yes, sqlbullet you are correct. Since posting I have taken two black bears that dropped on the spot or within 30 yards of being shot using the Hornady 250 FTX bullet.
I will be reloading with Hornady XTP for plinking but will stay with the 250 FTX for deer and black bear hunting.
Plus my 'friend' Tim Legendre had a lot to do with the 450 BM as it was originally called the 45 Professional.

Quote from: Riddim Guy on June 16 2015 12:18:18 PM MDT
The 450 BM uses the same bullets as the SOCOM.

Based on my understanding the 450 Bushmaster uses .452 projectiles and the 458 SOCOM uses .458 projectiles.  You can run .458 bullets through a die and size them down to .452, but they aren't the same family of bullets.

I have three AR-10 lowers looking for a build, and one AR-15 lower left looking for some love too.  I am intrigued by the idea of a big bore sibling to my 300 Blackout.  In AR-15 I would choose between the 450 Bushmaster and the 458 SOCOM.  In the AR-10 I have looked at the 45 Raptor wildcat and possibly the 375 Whisper.

Those of you that have decided on one or the other between the 450 and the 458, what were your reasons.

Sqlbullet, this .458 is my nephew's rifle, I'm just trying to teach & help him with loading for it. 

Here's a nice starter-

http://www.radicalfirearms.com/product-p/rfrifle.v2.16fhr-458.htm

It is a pretty good deal as their price is essentially the price you would pay for parts if you went DIY.  I already have all the needed tools to build AR15/10 rifles, so I will probably roll my own so I know the crush washer is on right and everything is torqued to spec.

There are some reports of poor QC/CS on this company, but also some guys got great guns.