For those that are contemplating purchasing a Ruger 10/22 and already own an AR, I would strongly suggest that you give serious consideration to one of these uppers....
Considering the cost of a new rifle and the normal upgrades that most people wind up investing in a 10/22, this is a serious alternative... I've built two 10/22s in the past years and my investments ran 450-$600 by the time I was finished..
When I install the .22lr upper on my DPMS lower, with the exception of the paint scheme difference, it's almost impossible to tell the difference between it and my .223 upper...
The weight and appearance are almost identical, I've wound up feeding 25 different brands/types of ammo through the upper in both slow and rapid fire situations and cannot cause a malfunction, short of attempting to get it to feed empty cartridge casings...
While various brands of ammo will provide different accuracy nodes or points of impact, the upper is certainly accurate enough for hunting or action competitions...I'm still out on Benchrest type match evaluation, due to the trigger group in my lower and less than perfect conditions existing at the attempts I've made in that area..
As you can see on the target board by my first attempt at 50 yards,,some ammo had drastically different results, while others were within acceptable accuracy standards..
These were shot on 3"x5" index cards and while later range sessions showed a little change for the better, wind conditions kept me from obtaining more definite results..