7.62 x 39 Subsonic 2 of ?

I used my Over All Length gauge and loaded up some of the big British bullets I use for my Ruger Bolt gun and they shot ok, were accurare and stable. They did not operate the action at all. I will need to keep looking and someday down the road buy another upper (hopefully from the same company because I just love this one) with a pistol length gas system on it.