I've had three. Two of the old "Armalite" made rifles, and one "Charter". By far, the old Armalites are the most desirable.. With some practice, they can shoot quite accurately, considering their intended application.. (extremely compact, low maintenance pack/survival kit rifle)
The biggest problems I've encountered has been the steady degredation of quality in the versions since Armalite quit making them.. The Charters were serviceable, but did not have the durability of the Armalites, and the "survival", and "Henry" variants did not lend much confidence..The plastic jacket over the steel barrel is the complete anthesis of the origional's aluminimum over steel barrel.(Intended to promote a very light,yet rigid barrel assembly)
Magazines are another issue. There appears to be ten junk AR-7 mags for each useable one.If you wish your AR-7 to work reliably, you need to test, tweak, and be selective of the mags you use.
If you are serious about one of these, seek out one of the Armalites, and find some good mags.. Remember this was neve intended to be a match rifle, or something you shoot every weekend.(Once a month for maintenance, or proficency is about it..) It is intended to be a tool kept in a pack for emergency purposes. Very few do this as well as an AR-7..
If you are just after a semiauto .22, get a Ruger 10-22..
Meplat-