Slim
Active Member
So, I have two 16” Colt barrels that don’t fit my needs. 6920 and 6721. They’re used enough that they won’t fetch collector prices, but have plenty of life left in them. With the increase in Colt prices, General lack of quality parts right now, but availability of AR machinist, I’m looking to cut them down to 10.3”.
Both barrels date from ~2009. The 6721 was a LE trade-in and had a fair (but not alarming) amount of port erosion as identified during a SOTAR armorer class last spring. The 6920 has been shot much less; zeroes and qualification mostly.
I’ve researched the “Crane Spec” for the OG CQBR/Mk18 and the rationale for the 0.070” gas port.
My question is, will a 16” barrel, cut to 10.3”, likely function without gas port mods? Both will wear a suppressor (M4SD, 30SD, SOCOM556) most of the time. Ammo will generally M193/M855, FBIT3M, or Mk262. Any unsuppressed fire will only be with duty-grade ammo.
Some obvious “it depends” unknowns are the actual extent of erosion, which I can’t really tell without (destructively) sectioning the barrel.
Both barrels date from ~2009. The 6721 was a LE trade-in and had a fair (but not alarming) amount of port erosion as identified during a SOTAR armorer class last spring. The 6920 has been shot much less; zeroes and qualification mostly.
I’ve researched the “Crane Spec” for the OG CQBR/Mk18 and the rationale for the 0.070” gas port.
My question is, will a 16” barrel, cut to 10.3”, likely function without gas port mods? Both will wear a suppressor (M4SD, 30SD, SOCOM556) most of the time. Ammo will generally M193/M855, FBIT3M, or Mk262. Any unsuppressed fire will only be with duty-grade ammo.
Some obvious “it depends” unknowns are the actual extent of erosion, which I can’t really tell without (destructively) sectioning the barrel.