While I was doing the 100 round break in on my MP153, the recoil spring got jacked up. It jams everytime now and I have to pry the recoil spring out from under the action bar sleeve.
On other forums, the indication is the gas adjustment is set too low; that the action was cycling too fast for the spring. I found the gas adjustment nut in between marks that indicates "fowl" play
. The instruction manual says there should be a mark showing where the factory setting should be, but I'm confused which marking is what? So the question is which is the factory setting; A or B?