I removed the gas key from the bolt for cleaning and I can't seem to get it torqued back enough to hold it during firing.

Has anyone else used loc-tite in the bolt? Is it safe from a heat/pressure standpoint?

Locktite is worth a try. If it doesn't work you'll have to stake them like the manufacturers do. Stakes aren't disolved by cleaning products and lubricants like locktite may be.

Quoted: I removed the gas key from the bolt for cleaning and I can't seem to get it torqued back enough to hold it during firing. Has anyone else used loc-tite in the bolt? Is it safe from a heat/pressure standpoint?

Absolutely.  Try blue first.  I know that Compass Lake Engineering was using Green LocTite to hold the gas blocks in place, but I'd only use green on the bolt carrier if the blue proved inadequate.  Either way, a little mild heat from a propane torch or soldering iron will soften loctite enough for removal.

The use of "Loctite" products is not called for use on the carrier key bolts. Manual calls for torque of 35-40 inch-pound. Staking in 2 or 3 places is called for. Mechanical locking will hold much better than "chemical" locking that will be affected the heat generated by the hot gas cycles in rapid or auto fire, along with the oils used to lubricete the bolt-carrier. All mine are properly staked.