Hi guys! I built an upper using an Adams Arms mid length piston system. It came with the gas block without the rail on the top. I currently have the Samson Evolution EX 9" tube on there. I'm a little turned off about the clamp on attachment of the tube. I'm hoping to find a tube that uses its own barrel nut and the tube bolts to that. I'm just not sure what will work with the piston system. And I LOVE that piston system!! Thanks for any help!!

the lightweight piston does not fit under any rails without major modifications (can be done, PIA IMHO).  Something else to think about when making your decision on a new rail or tube, the two piece rail allows you to remove the rail without removing the gas block for cleaning the back side of the gas block.

Good luck with a decision.

fatkid