Fulton Armory makes a 16" rifle length barrel..... So sexy!
If you like the idea of an adjustable gas block, you need to look into the JP (LMOS) Low Mass Operating System. The idea is to use the minimum amount of gas to cycle the rifle. The lower the weight of the cyclic mass, the less amount of felt function of the rifle.
They say that the felt recoil is actually 3 parts all felt in conjunction. First you feel the recoil of the shot. Next you feel the action pulling back and releasing the spent casing. The last you feel the bolt slamming back into battery.
JP designed the tank brake, the LMOS BCG, the adjustable GB and the captured buffer spring, all to address these issues. They sound great in concept. Since they were made by JP I assume they work and are very high quality. The problem is reliability. Even JP advises against using the parts in a hunting/combat rifle, where every pull of the trigger counts.