I am having a feeding problem with my guide gun. The lever is stuck open when I cycle to load a round. I have removed the lever, removed the cartridge 3/4 of the way in the magazine tube, and put the rifle back together. The rifle cycles fine when no rounds are in the magazine. When I attempt to load a round, the lever is stuck open again. I thought this original might have been the ejector, so I replaced it with the WWG bear proof ejector. Now I am thinking this may be a problem with the carrier assembly, loading spring, or magazine tube. Any ideas out there, previous experiences?