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...