Make sure it is unloaded. I use a pair of parallel jaw pliers, with appropriate padding, and grab the spring loaded pinned bolt and pull it down. Slide the stock off.
To get the colt aftermarket comp apart, you will need a padded vice, a spanner wrench and a heatgun or torch. the ends are threaded but have thread lock applied.
I have had my Colt for 1.5 years, and close to 5k rounds down the tube. No problems with the barrel, and I have found the rifle's accuracy is superb. With regards to the tensioned barrel, I have found the very small o-ring on the threaded end of the comp is fairly important. It is what centers the barrel in the shroud. With constant loosening and tightening for cleaning, my o-ring broke at some point and I never did find the darned thing. Accuracy went to hell without it. The only 0-rings I had in stock were the correct diameter, but thicker. So, I increased the chamfer at the muzzle end of the shroud to accept a larger o-ring. After tightening the comp to the desired torque, I used a center punch to dimple the comp at 12 o-clock as a visual indicator so I can consistently return to the same spot. A very small amount of lube on the o-ring works to keep the o-ring intact. I have not experienced the comp loosening up during use. Have you checked to see if your o-ring is missing? :thumb:TM
Back when I was into SKS's, I could get Chinese 120 round battle packs for under $20. But they were steel cored, and got banned. Even though the Russian ammo was also steel cored. If you want to drool and see what we are missing in the "Land of the Free", check out Marstar in Canada. And, no, they don't ship Chinese firearms to the US. >:( Scroll down to Norinco and check out the prices) TM