Who makes a good .22LR conversion kit for AR...

[missiontrails]

And who has some in stock?

[Saigon1965]

Ciener have a kit out - Colt used to make kits - You can go dedicated upper like the Spikes - CZ also have a dedicated upper -

[MonsterMan]

Spikes Tactical has great dedicated uppers for the AR. I love mine. They also have a drop in conversion kit for the .223 upper. I haven't tried that one though.

My Spikes upper is great as long as you use the .22 ammo that they recommend. I shot with it this week and it jammed on every single round of Remington .22 ammo I had. I also tried another brand and it jammed with it also. But once I tried the Walmart Federal 550 bulk pack, it didn't jam once. It was great fun to shoot. I wish it wasn't so picky with ammo though. Not very useful in my book if you have to stick to one brand of ammo. All my other .22's can shoot anything.