I have a question for the experts… I have a lightweight (6520) and want to cut it to 11.5 for a lightweight sbr. Are there any issues with cutting a peincil barrel?
You’ll end up with a smaller shoulder for the FH and washer to seat against. You’ll need some gas port work. Use a competent smith.
Clear. Thanks Skintop…![]()

Not a problems if you have a good company do the work. Colt pencil barrel cut down to 12.5", gas port opened for .mil ammo and can. ADCO did the work.
Why don’t you just buy a factory 11.5" Colt barrel and swap barrels?
I looked at that option myself, but the ~$300 price difference convinced me to just have ADCO cut mine down. I could’ve sold the 16" barrel to recoup some of the costs, but it was less hassle to simply send it to ADCO and wait a week.
Not to mention the scarcity of barrels at the moment. Unless you want to pay a hefty premium to the usual Colt suppliers, of course.