http://www.youtube.com/watch?v=6JmIQXkoog8
Here is a interesting video, may show a argument for the use of the POF roller cam pin.
Printable View
http://www.youtube.com/watch?v=6JmIQXkoog8
Here is a interesting video, may show a argument for the use of the POF roller cam pin.
I've got a POF roller cam pin in my Ruger SR-556C. The pin's been in the gun pretty much since new and I'm coasting up on 6,000 rounds fired.
The stud or shaft or body or whatever you want to call it has the usual wear patterns from its interaction with the bolt carrier but the roller is looking fine. It is still tight on the shaft with no signs of loosening.
I doubt there's any real benefit from the use of the roller but it doesn't seem to have caused any problems, either. I don't notice any increased smoothness in the action or anything like that. And I've still got a small amount of cam pin drag in my upper.
The LMT MRP upper has an angled cut in the receiver just behind the cam pin recess.
brent31, yeah that video shows what drag there is, we should see a similar test done with one upper using a lubed cam pin and a roller pin. I'll do it if nobody else hasn't already but I don't really have the time now.
That with a cam like move in the wear area (LMT MRP) apparently. I like, I like a lot. This maybe would help reduce "break-in" wierdness.
I think this is something that just might make the DI even more reliable, atleast it should operate for a longer time if the ultimate failure mode is attributed to the system weakening due to loss of energy.
I did try this in my LMT upper with a POF roller dry and could not get the BCG to bind like it did in the video.Quote:
brent31, yeah that video shows what drag there is, we should see a similar test done with one upper using a lubed cam pin and a roller pin. I'll do it if nobody else hasn't already but I don't really have the time now.
I can try, won't be till the weekend.
engineering never works like that. Everything is a compromise, and when you're working on a time sensitive project trying to win a military contract that's a part of the compromise. I do think it's a very good system and it really is the first modular adaptive rifle. This roller cam thing is neat, but i'm not interested in beta testing it. :D