well, i have been trying to decide which .22lr conversion kit to get.  i was initially excited that DPMS finally said the hi-caps were coming.  then i looked deeper and found out that the dust cover has to remain open.  i am going to build a dedicated upper that is near identical to my favorite 5.56 AR, and i want it as close as possible.  i wanted to give DPMS the business being in my home state and all.  seems kinda silly i know.  does the m261 kit work with the  dust cover?   if not it looks like the ciener is what i am going with.

Does the DPMS kit actuate the bolt catch?  The dust cover is hardly a concern for me.  Does it require a dedicated upper or will it work with a 5.56 barrel?

Dunno about the DPMS kit, but the dedicated upper does not activate the bolt catch. In fact, you can't even lock it open manually.

M261 doesn't activate it but you CAN lock it open manually.

As to not allowing the dust cover to close, that might be intentional. The 22 ammo might not have enough power to open it if fired with it closed. It's not a big point to me. I hardly ever close the dust covers on my centerfire ARs.

Don't know about the DPMS kit, but you can close the dust cover on the Ciener just like a .223 AR and the .22 is able to pop it open.   I thought there was a kit that worked the bolt catch.  Air Force M261 maybe?  

I wouldn't miss it on a .22, but since the bolt doesn't lock back* I've taken to using the dust cover as a sort of "chamber checked flag" for myself at the range by closing it when I've verified the chamber is empty.  

* = IIRC you can push the catch up and it'll sorta hold the bolt open, but not all the way, and it's easily bumped off and closed.

the DPMS kits can be had both as dedicated uppers or the slip in unit for .223/ 5.56.  the air force kit is supposed to lock the bolt back, but i remember peopelsaying that the lo0ck back function is finicky.  i am leaning towards the 261, but the $175 price tag makes the $115 for the JAC kit seem a little better.

<oops, double tap>

Don't forget to factor in magazines in your price comparision.  According to the Ciener web site a kit with three 10-round mags would be $139+35+35=$209 and on DPMS's site a kit with 3 mags would be $130+30+30=$190.

The best match for your 5.56 upper would be to use a drop-in kit in that upper, which may be adequate depending on your accuracy requirements.  But there are other reasons for wanting a dedicated upper, such as keeping the .22 gunk out of the 5.56 gas tube and not having to move the sights when switching.

Most dedicated uppers are built around a specific kit (modified to not use the chamber adapter) so unless you're going to use a KKF .22LR barrel (which still uses the adapter) or are just "dedicating" a .223 upper to .22LR by turning the gas tube over then I would start by picking my barrel and then get the kit that works with it.