yes , i have a model 1 sales dedicated upper for my 20" rifle and a spikes tactical conversion unit with my 16" carbine , both shoot well but i think the dedicated a tad more accurate , i have a ceinar conversion in my m16 A1 retro , it shoots great

ive given all of my kids/kids-in-law a conversion of one brand or another for each of theirs as well , none are extremely accurate but all are good enough to be fun and effective for practice , i cant think of a cheaper way to shoot them