Chambermates work but they have their problems like buring up the O-ring in 25 shots and make a mess of the guns chamber. Tried the teflon tape both gas and water types, neither work well. I have two sets of 20's and 2 sets of 410's for 20ga. The 20ga have two different size grooves to accept the O-ring, when I emailed Seminole and sent a photo showing the tubes with different size grooves, never got a response back.
If someone has a fix for the design flaw that causes the O-ring to burn out please share with the rest of us who purchased the Chambermates so we can enjoy using them.. GZ