Because of the heat of sustained firing, even red locktite would let go after a certain point. If you wanted to use a locktite, you would have to use green locktite, and then you would have a very hard time ever getting it off.
Consider making a notch for the indexing pin to sit in. It wont take you long and you will be able to install and remove it quickly without tools.
*** BUT *** Before you do that, you will have to be sure that there is enough metal to cut that slot. If you break into the expansion chamber, that wont feel so great when you shoot!