I have an old (cup and cone type) type Dura Ace 7400 BB, and the lockring on the adjustable cup side keeps loosening, introducing play into the BB

I assume this is not supposed to be happening

Am i supposed to put lock-tite or something?
Thanks guys

Teflon tape, and grease.

Had this problem with an old no name lockring on my hub.

lol dont use teflon tape, use a lockrign spanner and lock it down tight.

I run the same bb.

Are you using two tools to tighten the lock ring while holding the cup? Or do you just tighten the ring against the bb shell?

DO NOT USE LOCKTITE!

https://www.parktool.com/repair/readhowto.asp?id=93

well the first time i tightened it, i used the pin spanner to hold the adjustable cup steady while i tighted the lockring with the spanner. the second time, i only used the spanner -- its holding tight, but it's only been a day

BTW thanks everybody!

Has the bottom bracket shell been faced?
If the lock ring and frame aren't meeting up properly, it may be difficult to get and keep the adjustment you want.