http://desmond.imageshack.us/Himg59/scaled.php?server=59&filename=99626968.jpg&res=medium Here is proof that the germans are using the PTR m-4 tapco tube in battle. I use the magpul CTR stock,it looks more fitting,the tubes are solid.These stocks take the long screw thru the back ,unlike other u.s. made A2 stock knock offs. I have 2 of these backplates. They are no longer made. Tapco thought no one wanted them. They work GREAT.