I used to use the T/C Breech plug grease until the one evening I was unable to get the breech plug to come loose. I ended up snapping the wrench that came with the rifle trying to free it. I finally had to pull the scope and take the rifle to the shop. I poured boiling hot water through it and got it in a vice and finally with a 7/16th wrench was able to force it free. After that I switched to CVA Slick Breech plug and nipple grease and have never had a problem since.

I also loosen it after every 5-10 shots just to be sure. A stuck plug is not a fun thing to have....