My best friend who also happens to be my FFL Dealer, bought FIVE I O's back in 2010 and sold four of them to friends including me. The price was around $425.00 each out the door.
Not one of them would go through a full 30 round mag without hanging-up on an open bolt. Pull back on the charging handle and get a few more rounds out of it. Jam again. Always with the bolt hung-up to the rear.
Tried different magazines: same result. Seemed to be hanging-up on the receiver rails.
His, unfortunately was the worst one. Maybe three rounds before open-bolt jammimg.
Returned it to I O and received another, no-questions asked, that was just as bad. Thank GOD for the lifetime warranty.
After a third one with the same problem, he returned his, mine, and one of the others sold to someone who was made aware of the problem but insisted he could "fix it."
Other two guys kept them as safe-queens as they don't shoot much.
Not saying this will happen to you.
Just relaying an experience.
Easy company to deal with, but who wants to go through the hassel?
Needless to say, I do not have a good opinion of I O's.
Spent $1500.00 on a Firingline-milled-receiver underfolder and have had no problems after 500+ rounds.
You get what you pay for.