I'm building a 458 socom upper, mid or carbine length gas system?

I'm building a 458 socom upper with a 1:14, 16" barrel with brake and adjustable JP gas block. When ordering a barrel, should I order a mid, or carbine length gas system? The 458 is a low pressure round and reliability could be an issue mid length and the shorter carbine system might shred my very expensive brass. My only AR 15 is a mid length, M-4ish 5.56 and it's easy on my brass, compared to my mini 14 and 30. It would be good if the 458 socom was easy on the brass as a case costs close to a buck...

Carbine is all you need. If you haven't bought your barrel buy one from Tromix along with his bolt. He made the first 458 socom and his prices are good.

The carbine length gas system functions well IME.

I went down he road of building my own upper with an adjustable gas block and a bunch of expensive internals. Took a long time to get it to function right. I finally bought a complete Tromix upper and it ran great from day one. Now I have my home-built upper dedicated to heavy, suppressed, subsonic rounds and my Tromix for everything else.

If I had it to do over, I would have just done a Tromix upper build and saved a bunch of money and time getting it right.

But the "journey" was educational and fun.....

Thanks for the response, I've been to Tromix's website and might buy the barrel and bolt from them. I probably would have come out ahead buying a whole upper from Tromix, had I not already started picking up bits. Carbine length gas system is what I'll buy, thanks again...

Cant go wrong with tromix

Mid South has 450 bushmaster and 458 Socom uppers complete for $400.

I have the same question. In the .556 I don't recommend a carbine length gas system. On my match rifles I extend the rifle length gas system 2". I have zero experience with the 458 SOCOM but everything I have read states the carbine length gas system is the way to go with the 458 SOCOM.

My 458 SOCOM has mid length gas system and I shoot many 300 grain cast bullets through it with no problems in function or brass.

My understanding it's the length of barrel after the port - too short and pressure is lost when the boolit exits. With the adj. block you can tune extraction rate/timing which is what damages brass rims.

450 runs lower pressure than the 5.56. So while carbine length is overgased in 5.56, works great in 450. Most barrels I have seen for sale are carbine length system.

Mine runs fine as is w carbine system, standard gas block. But a really heavy buffer tamed the recoil alot. I see everybody w carbine stocks on 450s. I prefer the rifle stock and heavier buffer. Can get alot more weight in a rifle buffer than carbine.