Jump to content
bj139

Shot my new 458 SOCOM today

Recommended Posts

I shot my new 458 SOCOM today. I do not have a .875 gas block or a carbine length gas tube so I shot this in manual mode.

I have ordered a .936 gas block since a .875 was not available and a carbine length gas tube.

I took the side charging upper from my 6.5 Grendel since the ejection port was already large enough to eject the huge 458 SOCOM cartridge. The lower is an 80% I milled out on a drill press.

 

41377073591_1dda9a6a4e_c.jpg

I loaded ten .452 200gr swc. I had to push the necks into a 45 ACP carbide die to get enough neck tension but it worked.

9gr of Red Dot for a plinking load.

I also loaded ten .458 350gr copper plated bullets the normal way. 7gr of Red Dot.

The Lee dies have a mouth expanding die to ease bullet insertion.

I had some trouble getting it adjusted so I just used my Lee universal mouth expanding die instead which worked well.

41334990552_9b050cab80_c.jpg

The .452 rounds were used for sight in at about 12 yards.

Then I fired the 350gr bullets and got the two groups below.

All the fired cartridges ejected very easily with just hand pressure.

The unfired 350gr cartridges required mortaring to eject them when I was trying to clear an incomplete chambering.

41377073271_4a432c7114_c.jpg

During this time I had a persistent problem shown below. The base of the bullet popped out of the P-mag and was trapped above the ejector. I put the case into the chamber and pulled the bolt back slightly each time and let it slam home. I need to remove the ejector and taper the edges to stop this.

41377072881_49245c1263_c.jpg

One time when I let the bolt fly into a chambered cartridge I had my first slam fire. It make quite a crater in the ground.

I grabbed a handful of dirt and the bullet came out. It showed good expansion. I am glad I did not slam the bolt home at home or I would have had quite a hole in my floor. I will remember this for the future. These loads were very mild; sort of like light target loads in a 45 ACP pistol but fired in a rifle. The expansion in a full power load should be quite impressive.

41377072651_f6c1b27b0a_c.jpg

Edited by bj139
  • Like 3

Share this post


Link to post
Share on other sites

You have poor Google Fu

 

http://www.primaryarms.com/troy-industries-low-profile-gas-block-875-set-screw-style-sgas-875-00bt-00

 

you can even get it online from Walmart Shipping is Free to the store or your house.

 

354f51a0-c3c6-4677-a973-b6579b9913d8_1.2

 

https://www.walmart.com/ip/Troy-Industries-Gas-Block-875/23246500

Share this post


Link to post
Share on other sites

Some of the rounds you loaded don't seem uniform in the amount of bullet sticking out of the case especially the 6th lead bullet round from the left? Also the last plated round seem to be sticking out further. You might want to check them with a caliper?

Share this post


Link to post
Share on other sites

Looks good.

If your barrel diameter for the gas block is .875", That is the size your going to need.

Not sure how well a .936" is going to work out for you.

 

Glad you where outside with the barrel pointed down on the slamfire. That will definitely give you a good scare.

Looking at some other forums. The Lancer magazines seem to be the top choice for this caliber.

Please give us another range report when you get the rifle complete.

 

Thanks,

Glenn

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

$43 for a gas block? That is nearly half the cost of the barrel.

I was placing an order to Delta team Tactical anyway and they were out of stock on the .875 gas block so I will try to get the .936 working with some Yankee ingenuity.

I think the bullets look long due to the photo angle. I seated them to just cover the bullet lube groove.

The ones with lube produced more smoke since they were undersized with considerable blowby around the projectile maybe even burning some lube in the process.

They could be used in a pinch.

 

The slam fire was not scary since the loads were so mild. It was more of a WTF just happened.

It was scary afterwards considering the penetration of these low velocity loads.

I have been cycling rounds in the house to test function but I was careful to not do a full chamber seated slam.

Maybe I will try to think of a temporary firing pin block to make this safer.

 

I think I can bump up the Red Dot loads a bit. I used a reported Quickload estimate for a 500gr bullet in the SOCOM of 9.8 gr at 35,000 PSI.

I know the faster powders can raise pressure quickly so maybe 10gr would be good for the 350gr bullets.

 

This is like having a large caliber pistol in a rifle format.

Edited by bj139

Share this post


Link to post
Share on other sites

$43 for a gas block? That is nearly half the cost of the barrel.

I was placing an order to Delta team Tactical anyway and they were out of stock on the .875 gas block so I will try to get the .936 working with some Yankee ingenuity.

I think the bullets look long due to the photo angle. I seated them to just cover the bullet lube groove.

The ones with lube produced more smoke since they were undersized with considerable blowby around the projectile maybe even burning some lube in the process.

They could be used in a pinch.

 

The slam fire was not scary since the loads were so mild. It was more of a WTF just happened.

It was scary afterwards considering the penetration of these low velocity loads.

I have been cycling rounds in the house to test function but I was careful to not do a full chamber seated slam.

Maybe I will try to think of a temporary firing pin block to make this safer.

 

I think I can bump up the Red Dot loads a bit. I used a reported Quickload estimate for a 500gr bullet in the SOCOM of 9.8 gr at 35,000 PSI.

I know the faster powders can raise pressure quickly so maybe 10gr would be good for the 350gr bullets.

 

This is like having a large caliber pistol in a rifle format.

What barrel did you use?

Share this post


Link to post
Share on other sites

What barrel did you use?

I used the AR-Stoner barrel from Midway.

Delta Team Tactical has what looks to be the same barrel in stock now for the same price.

Muzzle threads are not 5/8-24 but are 5/8-32, I think. Not sure about 32TPI but is 5/8".

I usually leave them bare or put a thread protector on so I guess this will remain bare threads.

Edited by bj139

Share this post


Link to post
Share on other sites

You might want to look at some harder primers, and check to make sure that slam fire was an isolated incident.

If not you will have a problem when you load a full mag and send the bolt home.

Share this post


Link to post
Share on other sites

$43 for a gas block? That is nearly half the cost of the barrel.

I was placing an order to Delta team Tactical anyway and they were out of stock on the .875 gas block so I will try to get the .936 working with some Yankee ingenuity.

I think the bullets look long due to the photo angle. I seated them to just cover the bullet lube groove.

The ones with lube produced more smoke since they were undersized with considerable blowby around the projectile maybe even burning some lube in the process.

They could be used in a pinch.

 

The slam fire was not scary since the loads were so mild. It was more of a WTF just happened.

It was scary afterwards considering the penetration of these low velocity loads.

I have been cycling rounds in the house to test function but I was careful to not do a full chamber seated slam.

Maybe I will try to think of a temporary firing pin block to make this safer.

 

I think I can bump up the Red Dot loads a bit. I used a reported Quickload estimate for a 500gr bullet in the SOCOM of 9.8 gr at 35,000 PSI.

I know the faster powders can raise pressure quickly so maybe 10gr would be good for the 350gr bullets.

 

This is like having a large caliber pistol in a rifle format.

Buy another firing pin and grind it down so theres no protrusion in the bolt head.

 

I would definitely go with harder primers too.

Share this post


Link to post
Share on other sites

Feeding from a magazine absorbs much of the impact of the firing pin. I let the bolt go on a chambered round. Bad.

I last loaded 45 Colt with the large primers so they were probably large pistol primers left in the Lee auto prime.

The loading data I have seen for the 458 SOCOM lists large pistol primers. Strange.

Another firing pin with the end ground sounds like a good idea. I will get an extra just for cycle testing and grind it.

Edited by bj139

Share this post


Link to post
Share on other sites

I guess the 452 bullets were just to get it down range but hardly a good way to start sighting in. It's like throwing a three pound cat through an eight foot wide picture window.They get out there but that's about it. It greatly overworks the case necks if you go down that small.

 

Slam fires occur when being mag fed most times. The floating firing pin is the culprit and the soft primers. STARLINE brass (NEW!!) is cut for rifle primers and I would go to those in the future.

 

Loading new cases USUALLY requires a slight shoulder bump and a trim BEFORE you even shoot them. I don't get it but it is what it is. The 458 SOCOM board goes on and on about that.

 

Tactical Ammunition has your gas block. Tell them Greg sent you.

 

Greg

 

PS: They are a HOOT to shoot!!

Share this post


Link to post
Share on other sites

I wasn't sure where to start this thread. I noticed a few posts about 458 SOCOM in the general AR15 discussion so I went there.

Is this OK?

Share this post


Link to post
Share on other sites

Absolutely a good place. This is a GREAT educational thread.

 

Greg

Share this post


Link to post
Share on other sites

I took the ejector out and made a taper from the top and cut a few coils off the spring.

After reassembly, the cartridge then caught on the bottom of the ejector so I disassembled and tapered the bottom.

The cartridge then was hanging up on the bolt face.

The ejector does not throw the round as far as before the modification using the bolt handle. It should be OK once I get a gas block in place.

27528624408_ed269af6a9_c.jpg

 

 

I then used a small sanding drum in a dremel tool to taper the inside forward end of the feed rails. It took about 5 seconds.

The round now slants upward in the mag as shown. It was flat before.

The dummy round now fed in at least 3 times fine. It seems the mag rail taper now allows the back of the round to pop up quicker and straighten into the chamber.

The P-mag holds 11 rounds. I checked.

27528624618_6dab45fbbf_c.jpg

I loaded 20 rounds using the 350gr copper plated bullets and a heaping 1.3cc Lee powder scoop.

A level scoop should weigh 9.2gr so these should be high 9gr.

Like I mentioned before Quickload listed 500gr bullet at 9.8gr for 35,000 psi.

I used the Lee mouth belling die that came with the SOCOM dies. It expands at a more gentle taper than the universal expander I used before. It seems to be specific for .458 so it was too large for .452.

I will try to shoot these Friday. I gave up on the .452 bullets. I have to get more .458 bullets.

Edited by bj139

Share this post


Link to post
Share on other sites

Lyman lists some loads you might look at and Hornady also. I hope your cut ejector spring will kick them around fast enough for proper ejection m

 

Greg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×