Converting 5.56 to .458 socom.

Puffy93 · #1 06-08-09, 00:36

Has anyone ever converted a 5.56 ar to a .458 socom? I'm not talking about a complete upper, More like changing the barrel and bolt. What else would have to be changed? Would it be easier to just get a complete upper?

DRich · #2 06-08-09, 00:48

That's it...just the barrel and BCG. I did this exact conversion a few years ago.

Would have been easier to just buy a complete upper, though. The individual parts were not easy to find at the time and I ended up paying more for the parts than I would have if I just bought a complete upper. I don't know if that's still true today.

Herkemer · #3 06-09-09, 14:59

Hi!

I'd like to do the same thing. I always thought a modified upper reciever was needed also, wider ejection port or something like that.

If I can use any upper I want, that would be very cool.

As soon as my current build is done, the 458 is next!

Thanks,
Orvis

DRich · #4 06-09-09, 16:16

Yes, you have to enlarge the ejection port a bit, but you don't need any extra or special parts for the conversion.

Puffy93 · #5 06-14-09, 22:18

Thanks.

Would you hapten to if you coulp use PMags with it or just steel / aluminum mags?

newarowner · #6 06-28-09, 01:37

I'm still pretty new to the 458 SOCOM, but for me the PMags have worked great for the 300gr Corbon loads since they're relatively short in length. I really like the Pmags for that loading. I'm not sure if the Corbon 405gr loads wil fit in a Pmag though since the Pmags have a reinforcing rib that runs down the inside front of the magazine, and I have yet to purchase or handload any 405gr bullets. I do know that the 500gr Round Nose Soft Points that I hand loaded (COL 2.245") do NOT fit with Pmags. I use a Lancer or HK mag for those (regular GI mags would probably work fine for the long 500gr loads as well.) I don't think you have to, but I take a file and carve out a small notch in the front of the magazine to allow for easier manual unloading of the magazine. Just personal preference. I've seen/heard of others doing the same thing. Here's a picture of my HK mag that has been modified as described with a dummy 500gr SP round loaded.