the slidefire stock actually does work well.i have only used it on a 556 upper.i just put it on my new 6.8 for the quick pic. i have only used it for about 200 rnds.thinking about selling it as i have ready access to several f/a weapons. it is cool and does work as advertised,it just takes a little retraining of instincts to pull weapon into shoulder and push forend out slightly.if i had more time and ammo, shot placement would be as good as m-16 with practice. i even had a sheriff deputy check it out on the range.he thought it was a great idea.