Remington 870 Police Magnum Feeding Issue

[StingyGunner]

Background: Purchased the Remington 870P about 2 years ago, and have had it out to the range infrequently since then, but have put a decent amount of rounds through it with ZERO problems to date.

Issue: Tuesday I lightly lubed a few contact points and took it out to test some new ammunition. A couple shots in to the day, the gun locked up on the round it was trying to feed. I cleared it through brute force (reaching in and pushing the round back down to loosen the action, then shoving the forend forward again). I assumed it was the new ammunition and tried other brands that have been flawless in the past, and they too malfunctioned...every other round or about every three rounds. I'll post a picture when I can, but the problem is similar to the problem in this thread. http://forum.pafoa.org/shotguns-43/1...g-problem.html The difference that I can see is that my extractor is holding onto the rim of my cartridge when feeding.
870 jam.jpg

I assumed I'd never run into problems like this with a higher end remington shotgun, or at least a "duty" level shotgun. Any tips/suggestions?

See: Post #8