I just thought I would share my great experience with my new Nordic Components dedicated 22lr upper. This thing is built like my JP CTR-02 rifle and runs like it to. I haven't shot a lot of long range stuff yet but it has eaten two 550 boxes of bulk wallie world ammo without so much as a hiccup. I have improved my positional skills already with this thing on my JP lower at a fraction of the cost. Unlike the conversion I used to have it sets everything off with my 3 lb JP triggr. The black dog mags are great too since they are just like my AR's and the 50 round drum is a blast. Here is a link to their website.
http://shop.nordiccomp.com/NC22_c6.htm
http://shop.nordiccomp.com/NC22_c6.htm