Depinger for BullBoss

Hey all, I hope I posted to the appropriate category. My bottle brush depinger works very well however it travels over time towards the muzzle end and defeats it’s purpose. I installed about midway after about 6 or so fills the twang comes back pain in the butt! Anyone know where I can get a pro one here in the U.S. or another solution? As always, Thanks 
 
Buy rubber grommet that's very tight fitting from hardware or automotive store.

Either 3 or 4 of these...

Screenshot_2020-08-27-11-10-132.1610979422.png


OR! One or two of these...
Screenshot_2020-08-27-11-11-523.1610979422.png