It's called "the pendulum of pain" for a reason... They do look kool posing for your carbine class photo wearing ACU pants a black polo shirt, and, of course, sunglasses. 
No that is the only one that will NOT work because the fake buffer tube of the rifle has the lower extension go all the way to the reciever and the MCTAR-30HD will only fit around a bare round tube. I used an MCTAR-13 on my PC model and it works fine. Just pop off the stock, slide the adapter on and clamp it around the buffer tube lower extension, then put the stock back on. You will lose the shortest stock postion but who uses that?
Not sure without looking at it but you can't use one designed for a normal AR-15 buffer tube because the 15-22 integral tube has the lower extension for the stock notched lower extesion going all the way to the receiver for extra strength. A normal AR buffer tube has that stop short so the end by the receiver is just the round tube. And since you have to slide one on the end of the tube for the 15-22 you have to use one that has the lower cutout for the stock's notch extension. An AR-15 one with a round hole is put on by removing the castle nut and taking the stock off the receiver, putting it on and remounting the stock. Can't do that with a 15-22. What ever you get it has to have the round buffer tube hole and the cutout below that for the stock extension. Also can't use any of the ones that are designed to replace the locating plate below the castle nut. That is what I use on my real ARs. That QR type should be used up on the front of the handguard or way down at the end of the stock.
If it's what I'm looking for, then yes (for the front).
I don't use a sling every time I shoot, so QD is the best option for me. When I want to remove the sling, it's very easy to do and I'm not left with little metal parts swinging around or getting in the way.
I often go from single-point to two-point when I do use a sling. It's nice to have at least one rotation limited socket in the mix. Both is even better IMO. On my 15-22 I have a Troy pro grade QD mount in the back, and a Magpul RSA in the front. I'm not liking the RSA though. It gets in my way.
This is the style I like. They stay out of the way even if you have the swivel attached. The price is reasonable too.
Rainier Arms™ | Browse | Rail Mounted | Fortis Rail Attachment Point
It would be better if it had a socket on each side, so if you mounted it on the top or bottom rail it would be ambidextrous (I shoot lefty).
