amt seemed to always be hit or huge miss. I had a longslide ordered for months and finally cancelled it (patience, my butt i was 16 at the time). If you got one that was right it seemed to work forever and if you got one that didn't it would drive you nuts trying to get it to work. I have their knock off 10/22 and love it. all stainless, heavy barrel and plastic stock half filled with lead for weight. very accurate.
I would offer $350, at that you could send it off and get it work if doesn't when you get it.