So over the last year, I've bought 3 bodies from AO, and 2 of them have incorrect o-rings for ULE bodies. They're simply too small, and the detents are going too far into the bodies, causing friction on the bolt. For the longest time, I couldn't understand why my balls were shooting inconsistent. Now I fixed it, but need to buy a couple of new detents. Guys, please check to make sure you have the correct o-rings on the detents!