Cycle issues and cheap set screws - Guntec USA AR-15 Clamp On Aluminum Rail Height Gas Block Gen 2

My dads eyes are not good and couldn't use the iron sights like he was used to in the army on his ruger 556 he bought. So i bought this to replace the A2 sight gas block so he could mount a scope.

We installed and lined up this gas block and it would cycle inconsistently, we removed it and cleaned the gas ports but it appeared to not completely fit over the barrels gas port.

We put it back on and tightened the set screws and both heads twisted right off with very little torque, now im looking for another reliable gas block so he has a functional rifle.