[Czechbikr]

As I've said before, all of my AR's have been purchased assembled either complete or assembled upper and lowers and just pinned together. I have a 300 BLK Pistol and carbine and my first consideration was to buy a complete upper and pin it to the 300 BLK lower that's on the carbine. Simple, quick and allows me to change back and forth at will with very little hassle. Estimated price these days on a complete .458 upper however is in the range of 450.00 +/-, which ..combined with acquiring dies, brass and projectiles has been the reason I've hesitated to this point.

Then it occurred to me that I could probably just buy the barrel and swap it out on the 300 BLK upper and the cost of the barrel only is 140.00 plus shipping. What other expenses would be incurred to do that, considering that I may be able to borrow the tools needed? Time and effort needed? Heck..I could probably sell the 300 BLK barrel to reduce costs.

 

[youngandfree]

458 so com generally needs a larger ejection port than a standard AR size. So I'd say probably not.

 

[youngandfree]

https://www.brownells.com/rifle-par...socom-stripped-upper-receiver-prod107943.aspx. $70 for receiver. $140 foe your barrel.

https://www.brownells.com/rifle-par...-mp-sku078102007-105383-202842.aspx?rrec=true. Going to need a bcg, for $110.

You'll need a gas block and gas tube. Your handguard and barrel nut should be compatible. That's about it.

 

[terryb]

not enough difference in cost IMHO. Get the complete upper and that way you still have .300 upper. If you really want, sell the complete .300 upper. But considering the cost of lowers right now(still?), when you get some spare cash, pick up another lower and put the socom upper on it and have 3 complete ar's. The lower is really the cheap part. i just picked up 3 forged lowers for $100. I figured that had to be about the bottom price and that way the FFL fee was spread over 3 lowers

 

[Czechbikr]

458 so com generally needs a larger ejection port than a standard AR size. So I'd say probably not.

I found a YouTube video on enlarging the ejection port with a Dremel and stone. Probably have to give up the ejection port cover.

I looked again and 450.00 was a low estimate now...more like 550-950.

 

[terryb]

prices are rising. an AR10 upper i should have bought at $399 when i ordered the lower(just before the florida shooting) is now $499 and almost all the configurations are out of stock.

I found a YouTube video on enlarging the ejection port with a Dremel and stone. Probably have to give up the ejection port cover.

I looked again and 450.00 was a low estimate now...more like 550-950.

 

[flareside_ford]

I am a tinkerer so I say assemble your own upper. Someone used to offer a bigger ejection port door to fit the bigger cartridges. Also you only need the bolt not the whole bcg. I want a .450 Bushmaster upper. I think the pistol diameter bullets that the Bushmaster uses are designed for the velocities achievable with the cartridge. Plus you can plink with cheap .45 ACP bullets.

 

[Czechbikr]

I am a tinkerer so I say assemble your own upper. Someone used to offer a bigger ejection port door to fit the bigger cartridges. Also you only need the bolt not the whole bcg. I want a .450 Bushmaster upper. I think the pistol diameter bullets that the Bushmaster uses are designed for the velocities achievable with the cartridge. Plus you can plink with cheap .45 ACP bullets.

That's a definite plus. What does it take, a Glock magazine with some kind of adapter?

 

[RedOilMan]

Bolt carrier groups are different from 300blk. I have a complete upper I carry in the same case with a 556 anderson rifle and change out at will. The cost of dies is nothing compared to buying rounds from the store. I load with barry's plated bullets and brass i have bought on sale. The price comes down considerably after a couple of reloadings. Besides that you will like it!

 

[Capt Rick Hiott]

https://tromix.com/shop?olsPage=t/458-socom

 

[Czechbikr]

https://tromix.com/shop?olsPage=t%2F458-socom

Thanks for the link. Now you've added another thought into the mix...I could use a 10" barrel to modify that 16" 300 BLK upper and use it on my 300 BLK pistol lower. hmmmmmm

 

[Capt Rick Hiott]

Hahahaha,,,,sorry.


I had a .458 SOCOM,,,but like a dummy I sold it. Ive been thinking about getting another one.........

 

[flareside_ford]

That's a definite plus. What does it take, a Glock magazine with some kind of adapter?

The .450 Bushmaster is a full length rifle round designed for the AR. I just meant that it uses .452 diameter bullets instead of the .458 diameter bullets the Socom uses. I am not aware of any .45 ACP AR that does not use a special lower. My GWACS poly lower has a wider section in the magwell sized for grease gun mags.

 

[GreenWolf70]

The .450 Bushmaster does exceed the performance envelope of .45ACP bullets by quite a margin. From what I hear people are saying you need to use bullets meant for the .460 S&W.

The .458 SOCOM matches up well with any jacketed bullets suitable for the .45/70. All lead .458 bullets will work as long as you use gas checks. Magazines can be an issue. All GI aluminum mags work great, but the only plastic magazine that works for me are the Lancers. I cut out a half moon on the forward lip of my SOCOM mags to clear 400 grain flat nose remmys. Your mag goes from being double stack to single. A 10 round mag holds 3 rounds, a 20 round mag holds 7, and the 30 round mag holds 10 or 11 rounds. My SOCOM kicks about like a gas operated 20 gauge auto shotgun.

I believe Aero Precision makes a stripped .458 SOCOM upper, if you don't relish milling out your own. I would also advise using Strike Industries enhanced port dust cover, Shopping

You will require a larger diameter gas block (I recommend BTE's adjustable micro) for the .458 SOCOM's larger diameter barrel. The SOCOM uses a normal spring/buffer (rifle or carbine) and a MILSPEC BCG. I would suggest buying the bolt with the barrel so the headspace is assured, but this is probably not necessary with current specs known. I bought mine years ago before the specs were really known and I tried using different buffer weights before going back to the standards. Best to just use standard recoil spring/buffer/BCG and an adjustable gas block. Tuning it with an adjustable gas block for smooth operation is much, much better/easier than changing springs/buffers.

When I first started thinking about a SOCOM, the consensus was to NOT use an adjustable stock. I haven't kept up with those forums for quite some time, so I don't know what the consensus is currently. I have my SOCOM mounted on a Cavalry Arms one piece poly lower (now GWACS). I have 2 of these lowers and I love them. The other is on my .300 BLK upper set up for supers. These things are great. They are lighter than a MILSPEC lower assembly would be by at least half a pound and much stronger. They are also very easy to modify, as Bondo works on them like nothing else and is almost impossible to distinguish as long as you finish it the same as the surrounding area. My second one of these lowers was part of the CAV AID 2008 charity drive to save Cavalry Arms from BATFE. They were manufactured by volunteers and the QA was not the greatest. I thought my magazines fit a bit too loose in the well, so I used Bondo to tighten up the fit. I also filled the gap between the upper and lower, like you would tighten the body panels on a custom car. I can not tell where the Bondo was used, and I did this almost 10 years ago. You can use any spray paint that adheres to plastic to finish. I also drilled and epoxied in QD sling mounts on both lowers.

Here are my two builds on this lower. The black one is the Blackout and the camo one is the SOCOM.

 

[NativeTexan]

You think 450 is bad? Try to find a .450 Bushmaster upper for less than 600 bucks. Price of brass is cheaper on the Bushy is why I was looking into it. In the end, I just worked up a good hog load with a Barnes bullet for .223 and lived happy knowing it'd kill a hog just as dead. And, if I wanna burn a hundred rounds of ammo on a gong target or something, it's a LOT more affordable shooting .223 factory ammo and I don't have to mess with reloading it.

 

[Yissnakk]

I found a YouTube video on enlarging the ejection port with a Dremel and stone. Probably have to give up the ejection port cover.

I looked again and 450.00 was a low estimate now...more like 550-950.

Keep an eye on Primary Arms - they've had several sales on .458 SOCOM with a Barrel and BCG for under $200 several times in the last couple of months.

Also, you won't lose the dust cover - the port needs to only be widened vertically by a few thousandths - it's not anywhere near enough to lose the dust cover...however, Primary Arms has "official" 458 SOCOM uppers (stripped or completed, minus barrel, BCG and so on) for $80, and those also go on sale often.