It does sound like you are getting basic bolt stick due to a carrier size that is too tight. Install the next larger carrier size. You want to use the largest carrier that does not produce a leak using the same white carrier oring. The smaller carrier sizes cause bolt stick and a leak because they don't allow the bolt stem to slide in properly and they push the carrier assembly farther back in the powertube while keeping the bolt stem vent hole exposed so that it weeps air. It stops the bolt short of being far enough back to reset the sear.
You should keep a range of carrier sizes. You never know when you might damage a carrier oring and need a new one. You need to adjust the tension of the new oring using the carriers.
Also, remove all the shims from the powertube. They can cause you to experience false leaks which result in you using a carrier size that is too tight for your setup.
If you use a longer or stiffer bolt spring, you need to increase the pressure/velocity setting to offset the increase in spring tension.
Except for the Automag in front, its usually the man behind the equipment that counts.