Numbered from left to right
1) RRA Semi Carrier
2) DPMS Semi Carrier
3) Milled Carrier for use with RLL
4) 9mm Carrier milled for use with a RLL
I signed up to reply to your question. It can be overwhelming trying to figure out all the little things that will make your RLL run flawlessly. If you use a stock DPMS carrier as pictured above you will beat the living $@#! out of your paddles. The key to having your paddle make contact with the back of the carrier is to hit a flat surface. If you look the DPMS is curved in the back where your paddle will strike. The DPMS is close to SP1 specs but not quite there. Definately a really bad idea to try and use it. Not that I have ever tried. The Rock River Arms carrier is even further away from where you want your paddle to hit. Why spend $8k on a link and not get your carriers properly milled? You can even do it at home with a steady hand, a Dremel, Needle Files, and a Caliper. Just go slow, you can't put back material but you can always hand file away the last few millimeters. Or better yet send it to someone who has the right equipment.
Threaded Mode