Loctite® 243™ Primerless Threadlocker is an oil-tolerant, removable, medium-strength, blue threadlocker designed for locking and sealing threaded fasteners ranging from 1/4" to 3/4" (6 to 20 mm). It works effectively on both active metals (such as brass and copper) and passive substrates like stainless steel and plated surfaces. It can tolerate minor surface contamination from various oils, including cutting, lubrication, anti-corrosion, and protection fluids. Loctite 243 has a temperature resistance of up to 360ºF.
Apply a small amount to barrel threads and set screws to help prevent compensators from backing off. This can also be used on other screws such as optic mounting screws.
