this would be done for a posty AR15 pistol. dont tell me the crap about its pointless and it will have the ballistics of a .22 mag. i am well aware of all of this. i just wanna know what it would take for the mag to be legally non-detachable. an SKS mag is fixed, but can be removed by talking the gun apart. if i would but replace the mag release buttom with a solid nut that didnt allow removal of the mag without pliars or something to remove the nut. i think that if it requires unscrewing sometihng to get the mag out it shouldnt be considered "detachable." it i replaced the mag release button with a peice of metal that fit in the fenced depression, and topped that off with a small nut. maybe a ATF letter would say no, but im thinking it would get by if i ever was questioned about its legallity.