BudsGunShop.com - Barrel rate of twist and chrome lining

Jeffrey, this has a 16" Barrel with a 1:7 Twist Rate. Most sites are saying it has a chrome lined barrel, but a few say Salt Bath Nitrate Barrel. It doesn't say on Bushmaster's web site, although it does say it has a Salt Bath Nitride MPI Bolt Carrier Group. For a definitive answer, I would contact Bushmaster at 800-883-6229 M-F 9am to 4pm, or email info@ bushmaster.com. Bushmaster web site here >>> bushmaster.com/m4-patrolmans/

Jeffrey, yes Sir. The Quad Rail Patrolman's Carbine has a 16" 4150 Chrome Moly-Vanadium Barrel. It is chrome-lined in both bore and chamber with a 1:9 twist ratio & A2 birdcage-type flash suppressor. Cheers and stay safe!

Yes.
The Quad Rail Patrolman's Carbine has a 16" 4150 chrome moly-vanadium barrel. It is chrome-lined in both bore and chamber with A2 birdcage-type suppressor. The free-float quad rail fore-end increases accuracy and enables accessory mounting. The Patrolman's Quad Rail Carbine utilizes a six-position telestock for light weight and quick handling.
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Oh and while some retailers list this as having a 1:9 twist bushmaster lists it as have a a 1:7 twist.
bushmaster.com/m4-patrolmans/

Yes, this has a 16 inch 4150 Chrome Moly Chrome-Lined barrel with a 1:9 twist ratio. Hope this helps.