Questions about crushing a scope tube?

[Onmilo]

15 to 20 inch pounds on the torque wrench is usually plenty.
Some heavy duty rings require up to 35 inch pounds when used on heavy recoiling rifles such as the elephant guns and Browning .50 rifles.

 

[DBR]

IMHO Loctite is a good idea on a scope you expect to leave mounted for a while.

FYI:

Blue Loctite is the recommended grade for things like scope mounts. Degrease the threads, the Loctite acts as a lubricant for torque readings.

If you are really paranoid regarding Loctite, use the Purple Grade. It is weaker than Blue and is usually used for instrument adjustment screws.

Red Loctite (271 and 272) is intended for things you are not planning to take apart. 271 is normal temperature grade and releases at about 300*F. 272 is high temperature grade and releases at about 500*F. IMO neither is appropriate for scope mounts.

Loctite 290 (green) is wicking grade and is intended to be used after the screws are tightened. It is nominally the same strength as Blue but because it is wicking it can cover more threads on the engaged surfaces and be harder to break free.

 

[DBR]

I have found "Liquid Wrench" to be useful in releasing Loctited fasteners.

Particularly with the wicking grade Loctite 290 it tends to get on the out side end of the fastener so the internal threaded part has to ride over the cured Loctite on the fastener threads. The "Liquid Wrench seems to soften the Loctite and lubricate the threads to make removal easier.