I did a little research into the AR-7 years ago. There are quite a few different manufacturers (Armalite, Charter Arms, etc.). I remember being told that one version is quite good and rugged, and at least one version is cheaply-made junk.
Sorry, but I can't remember who made which version.
I had the Charter Arms pistol version given to me by someone who couldn’t get it to feed right. I couldn’t either and I’m a fair gunsmith.