Receiver bending while heating up the mag tube

For rusted parts that is true, for this application heat is only needed to defeat the loctite. I heated the inside of the tube for a few seconds and was able to unscrew by hand.

I think the industry calls it "shrink fitting", where parts with close tolerances will not fit together unless the female part is warmed and the male is frozen. I think you are right about the heat relaxing the thread lock materials in this case. When I changed my original out for the CC titanium,, after cleaning the receiver well with a dry rag, I screwed the new mag in tightly by hand without using any thread lock. It dawned on me then that removing it may be difficult since it screwed in farther than if both parts had been the same temp. Sure enough, when I replaced the CC tube with a Benelli, it was so tight I was planning on warming the receiver again, but it finally snapped loose using all my grip and strength, and a little bit louder grunt.