Maruzen shot shell grommets

[tunabreath]

Since I added the mag extension to my M1100 rev3, I've been encountering a whole slew of new problems, the most annoying one being due to the shot shells themselves, not the feeding/extraction mechanisms.

The front grommet has become too loose over time. It still seats in the shell quite securely, but it no longer holds the BBs in very well. With BBs loaded into the shell, a vigorous shake will jar the first BB out the front. This did happen before I installed the extension, but is exaggerated now due to the higher compression from the longer mag spring (and the consequently rougher stop-and-go action).

Usually, the first BB from every shot will pop out as the shell is fed. Most of them fall out the bottom, but occasionally, one gets jammed up in the works. This usually either jams the shell lifter, which stops feeding, or jams the bolt, which stops extraction. A couple good tugs on the bolt usually clears it, but considering how often it occurs, it's obviously a less than ideal situation in a game (or even plinking for that matter).

Is there any way to swell the front grommet? Are they made of the same material as mag seals? Would soaking them in silicone oil be effective?
If silicone oil does work, will the grommet maintain a degree of slickness (after cleaning) that would potentially negate any improvement? Is there any other material (non-lubricant, non-corrosive) that would be similarly absorbed by the rubber?