I just wanted to post some results of a side by side comparison of my Direct Impingement Mk 12 MOD1 SPR (Compass lake barrel LMT upper Knights rail etc. All good stuff) and my POf M4.
This started out as more of a test to find out what buffers and buffer springs were best for my particular combinations. At the end of the day I realized why I prefer my POf piston powered AR to my other ones.
My SPR is a very smooth shooting rifle. Its extremely accurate and Im not putting it down in any way. That being said I found out that I had to have the right buffer, the right spring , and the right ammo for it to fire reliably , with the least amount of recoil.
I fired wolf , Lake city, and Black Hills ammo with these different buffer and springs. I had short stroking issues and bolt hold open issues. I did find a good combination that I am now satisfied with but can only use the Black Hills ammo for it to shoot reliably.
After I was finished with my SPR , I figure I would see what the POF would do with different combinations. Well It fired everything , in every combination. I could not get it to jamm with anything. 0 malfunctions.
The only difference that I found with the different buffers and spring was felt recoil and muzzle rise. The MGI RRB and 2x spring were the best for the POF. The ISMI spring with a H3 buffer came in a close second and a much cheaper alternative.
I did all of this testing with my recoil spring and cup that fits on my operating rod in the piston. This prove to not only be reliable but help reduce recoil even more. My POF is awesome. Today proved what operating system is the better of the 2. Im sold on the POF and I hope others realize this too. Thanks POF for a great design.