This is the same AR15 service rifle barrel used by champion shooters at Camp Perry matches, and by US Military personnel in their Recce and SPR Rifles. It is the barrel we chose for our Recce Rifles.
In .223 Wylde Chamber (equal to 5.56x45 NATO chamber), it is 16 inches in length with a 1-7 twist, this barrel meets the same rigid specs as White Oak's Service, Match and Varmint barrels, allowing you to get extreme accuracy in a shorter length barrel. This barrel has m4 feed ramps and a mid-length gas system. Diameter at the gas block is .750". Does not include gas block.