Hello, I have an older Mark I that was brought to me because it jams. I test fire it and sure enough the cartridge tries to climb up the feed ramp and stops the bolt when you try to load the first round from the magazine. If I try to hand load the first round it will climb the ramp and lock up on the second round. Cannot even fire two consecutive rounds out of this thing. Initially I polished the bolt face and the feed ramp, no change.
I clean the gun real good and get a new magazine. Same thing. I see all the posts on the web about rounding the sharp corners and try that...zero change. I adjust the feed lips and give them a good polish and that solves the climbing up the ramp thing, but now that i can actually load and fire the gun the bolt ends up on top of the "next" round and jams it that way. It is as if the bolt is short stroking. This doesn't make sense because the gun will positively eject the fired round. Now I am thinking some kind of timing issue. At this point you can load a magazine and hand cycle the action flawlessly. It loads, extracts, ejects and reloads no problem...just not when you fire it.
I take the gun completely down looking for a problem and find one. I really thought I had it...the magazine button was dragging on the inside surface of the right side walnut grip panel. I give it plenty of relief and head out to shoot it just knowing it will work...nope, same thing. I know that the bolt is very fast on the Mark pistols. What seems like a short stroke cant be because the fired round gets ejected perfectly, but for some reason the bolt ends up over top the next round and wedges between the round when it tried to get up the feed ramp.
It cannot eject the fired round until the bolt is well behind the next round in the magazine, so it seems like the only way the bolt could get on top of the round instead of behind it is if there was a delay in the round coming up {again, I know the bolt on these things is very fast} or the magazine is sitting too low in the receiver. Doesn't seem like it is sitting too low because, again, it cycles fine and picks up every round when cycled by hand {way slower, back to the timing thing again.}
For what it's worth, the owner says it has been shot a lot, but nothing appears to be worn. There is moderate peening on the breech of the barrel by the bolt, but everything else looks fine for its age. This is an early one. This gun is whistle clean, and the bore is perfect. The new magazine feels like the spring is heavier or stronger than my pretty new Mark III Hunter and definitely heavier and harder to load by hand than the old magazine. Thanks in advance for any info!!!!! All replies are greatly appreciated.
