I have at least three greens in my shop
Loctite is complex. Colors are re-used, to confuse us. Use numbers instead to be sure what you are getting.
While not exactly a lay guide, so not easy to understand in full, this is the best anyone has given me to figure out which to use where. The list on page 9 is pretty complete, others are shorthand, most-used ones.
first, I'm no officially trained armorer, mechanic etc ... I'm a shade tree of all these skills, that said, I have spent a lot of time cursing in the shade of a tree OJT'ing these skills
My OJT lessons on LocTite "colors".
I use LocTite blue, "medium". I haven't had a problem so far on weapons. Super low sample size, of course, but I do run my gear pretty hard for a civilian training. Several thousands of rounds per year between rifle and pistol (more pistol using pRDO) and haven't had a problem. I'm very paranoid about nuts/bolts/screws from my time in Naval Aviation wire wrapping nuts on to make sure they don't fall off. I check my screws/bolts/nuts before and after events to make sure they are secure and "blue" has never let loose on me. FWIW.
I DID have a problem with LocTite Red High Strength.... HOLY SHIT .... I almost passed out trying to get it off before using a heat gun. I didn't know about "permanent" and the heat gun thing (see shade tree) but I'm built like a gorilla and know my way around breaker bars, prior to this event never met a bolt I couldn't get off ... well, learning occurred.
Rifle barrel nut, in vise, breaker bar (country boy assist) and a LOT of huffing and puffing ... NOTHING.
I read the FUCK out of the LocTite when I buy it in the store now to make sure I don't buy or use the permanent stuff unless I KNOW I want it.
If I put "red" on any of those tiny PRDO screws, I'm not sure if it can be taken off without destroying it. If I made that mistake I would probably walk it to a real armorer and see if they could manage.