BudsGunShop.com - Threaded barrel cap

Dave, some manufacturers have a bad habit of using loctite or something similar. The best way to remove it would be to heat the cap. You can use a blow-dryer or something similar but the best and funnest way to heat the barrel is load up a couple magazines and shoot them as fast as you can/mag dump. Then try removing the cap. You can also contact the manufacturer at 1-800-290-0065 Option 3 or email them at customerservice@americantactical.us hope this helps.

Dave, you can try heating with a blow dryer or other source if you have thermal gloves. I would contact American Tactical Imports Customer Service for advice at 800-290-0065. Cheers and stay safe!