HELP: Stuck scope mount screw

S

Sea Buck

New member
I bought a rifle recently. An unblemished model 70 XTR.(I thought). I want to change the scope mounts. Bubba overtightened the screw in the rear mount. Hex head cap screw. Won't budge and I don't want to round out the hex or strip it out.
The mount will move slightly with a couple taps from the plastic mallet. I soaked the screw in Triflow overnight. No dice, won't budge. HELP, any hints would be appreciated.
 
You could try applying some heat to help the oil reach the threads.
I like PB Blaster

Using a straight hex wrench and some vice grip pliers, you can also try tapping downward lightly with a small hammer while applying torque. Often the shock will break the threads loose.
 
Thanks. I looked in "search" and have made up a 50/ 50 (about) solution of ATF and acetone in a baby food jar. I have a couple drops on the screw and recess with my bench lamp about 2 inches away. I will leave it for an overnight and gingerly try it again. I am open to any other ideas. I just hope I don't have to drill it. I have had that nightmare before...needle nose vice grips, etc.
 
Soldering iron with a fine pointy tip applied directly to the screw. Then tap it with the wee hammer(think tack hammer) and vise grips. The soldering iron won't heat anything else and will loosen any Lock-Tite.
 
...Bubba overtightened the screw...
Click to expand...
Or used loctite on it. The posts recommending the tip of a solder gun are likely most appropriate...just oil will not affect Loctite, it needs heat if it is one of the high strength varieties. Over doing it with force can result in worse problems than you have now.
 
"Soldering iron with a fine pointy tip applied directly to the screw."

Follow that immediately by sticking the proper sized bit in the recess and hit the end of the bit with a medium hammer. This treatment has always worked for me.
 
I've lightly tapped a corresponding torx driver into these before and was able to get enough bite to turn them out. You basically broach the hex feature into a torx feature.


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too tight

If nothing works, drill into the screw and using a hand tap handle with the proper size easy-out turn counterclockwise so that it digs into the drilled hole you made.

This will usually brake the grip of the screw.
 
If nothing works, drill into the screw and using a hand tap handle with the proper size easy-out turn counterclockwise so that it digs into the drilled hole you made.

This will usually brake the grip of the screw.
Click to expand...

I suspect that you haven't seen many scope mount screws. Where do you get an easy-out for a #6 or #8 screw?

Minor diameter on a #8 is about .13", on a #6 it's about .10".
 
Since there were no issues with the front screw, I ruled out threadlocker- though I thought initially red may have been used instead of blue.

Put the receiver in a mill/drill press vise, fit the tip into the chuck lower the quill with a lot of downward pressure and turn the spindle by hand.

If you've tried penetrating oils, heat, vibration, etc. and nothing has worked it's time to let 'er rip. Maybe it'll come out, or strip, or snap off. But, if leaving it in isn't an option there comes a time to deal with the unpleasantness and move on.

It's probably a #8. drill out/tap for #10-32.
 
Success: Thanks for all the comments. This forum is really great. After soaking the screw with the 50/50 mix ATF/Acetone overnight with my bench lamp about 2" from it. I put the correct 7/64 bit in and gave it many sharp raps. Also on the side and ends of the mount. (After my 3AM pee call I did the same thing...immediate feed back from the little lady!!) Anyway, I took a # 15 torx bit and tapped it in as the 7/64 was slipping a little too much...I tapped and turned, with pressure, for a couple of cycles and SUCCESS! Thanks again for all the comments, I really appreciate them.
 
As a side note, some of the bore cleaners, like from Hoppes and such, will dissolve even the red loctite, even if you don't want it to do that.
Just be sure to not let it run into the action are re-solidify.
Don't ask I know not to do that.
 
Be sure you determine what the problem was before running another screw in...if the threads are fugged up you may need to chase them with a bottoming tap- probably a good idea, anyway.
 
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