the feed port does not appear to be on center of the feed block in most of the pictures I am seeing. What about the possibility that the feed port is in the wrong place? That would put it in the wrong location in relation to the bolt face. I don't know the order of operations they used for making the feed block, but if they put the key and boss on the wrong ends after machining the feed port it would probably move the feed port about that much.
I agree, and this would lead to my aforementioned autococker-with-ball-partly-down-the-barrel-resulting-in-low-velocity analogy, correct?
Its easy to check. Measure the front of the feed block to the front of the feed tube and compare between OPBN and Sniper42. A ruler would work, its more than 1/8" its out.
I agree. We're building quite a list for these two volunteers.
Either that or all of the machining on the bottom face is set .150 to far to the rear. That would also require that the sear hole was buggered too. I can't see it firing if the sear hole was in the correct position and the frame and valve were trailing by .150. I seem to remember a video of these being manufactured on a 4th axis, so I can't see this being likely. Unless its a setup part that should have been scrapped out.
I would love to get my hands on the process sheets/drawings. It all depends what they used for datums for all the various features.
Having the bore from the back be .150" deeper than others shouldn't make any more difference than a softer spring would. It should in theory allow the bolt to travel farther forward past the feed port than it needs to, not allow it to set back farther.
I agree. However, my hypothesis isn't about the distance from rear field strip screw hole to bolt spring seat. It is about the distance from rear field strip screw hole to breech and other features all from the same datum - the rear field strip screw. See my list of dimensions I would like to gather from various bodies in this thread: https://www.automags.org/forums/showt...-2k9-mag/page2 We have not yet verified these are the same between functioning and non-functioning bodies. If the bolt releases the power pulse too soon relative to the breech/barrel geometry, it could lose much of the pressure up the feed tube.