Weird WTF jamb?

[BD1]

So, I replaced the new spring with the old spring, and the rifle runs again. However, I also took a close look at the chamber, throat and barrel with a fiber optic inspection camera. All look good, but as I was doing that I noticed that the ridge in between the M4 feed ramps of the barrel extension comes to a sharp point. That point has not been beveled as is the case in my other ARs with M4 ramps. That explains the little divots in the shoulder. My current hypothesis is that the new recoil spring added just enough extra speed to the bolt carrier that it was spiking the shoulder of the cartridge on that sharp point between the feed ramps causing the cartridge to tip down on the way into the chamber leading to the bend, and the jam. I had intended to pull the barrel and bevel that point and polish up the ramps this week end, but I am out of polishing tips for the Dremel and no-one in town has any. So I ordered some online and I'm shooting it the way it his until they get here and I have a day to tear it all down to do the work. I'll get some pics when I have the barrel out.