I have one and I like it. Very reliable and get the mags at ar57.com they are the makers of that upper. The mags work great and are way cheaper than the FN mags. I saw somewhere where they had a combo package the upper and 5 mags for under $600 new. I would do more searches. Sorry I cant remember the name of the company but i found it on arfcom (ar15.com) I have a special "device" for that caliber I plan on thinning some hogs out when I get a change. It really is a cool upper. Only problem is the scope/red dot. You have to get a removable mount like from La Rau if you want a scope or a small red dot like the new EO Tech.