Scope went for a walk. Use locktite??

[coloradokevin]

Short version: Scope moved rearward in the rings by 0.15 inches sometime during a brief trip to the range. Do I need more torque on the scope ring screws, or locktite on the screws that hold the rings together?


Full story: I just got back from a range trip with my new rifle. In two range trips in the past week I've put approximately 30 rounds through my new Tikka Scout Compact Tactical Rifle (.308 Win). I'm using a Weaver Grand Slam Tactical 3-10X40 scope, mounted in 1-inch TPS rings.

The good news is that my scope was on paper right off the bat, and it only took about 1 mil of adjustment to bring things in to center. Today I ran 10 rounds of match ammo through the rifle. The first group just broke the edge of the 1-inch bullseye, with a nice 0.67 inch grouping. The next two groups spread out a bit, to 1.5" and 2.5" respectively.

I got home tonight and was cleaning the rifle when I noticed some light abrasion marks on the scope tube, just forward of each ring. A closer inspection revealed that my scope had moved rearward in the rings by approximately 0.15 inches (I had marked the scope tube with pencil for eye relief setting during the original mount, so I had a good reference point).

Obviously this movement is undesirable, and I suspect that my sudden loss of accuracy could be because of this movement. But, would I be better off adding more torque to the adjustment screws, or should I just throw some locktite on the screw threads?

NOTE: I don't currently have access to an in-lbs torque wrench (might need to find one), so my initial setup was a guesstimate on the torque required to hold the scope!

There's nothing like a mobile scope to add some frustration to this sight-in process!


Thanks for the help!

 

[WardenWolf]

Both. Torque it down a little more, and use blue Loctite to keep it there. Don't use red, unless you want it to be there forever.

 

[madcratebuilder]

I would not exceed the recommended torque settings, it can damage the tube. I would use some gun-tite (purple loc-tite) or blue. Use heat from the tip of a soldering gun the break the grip of the loc-tite when disassembling.

 

[Zach S]

Purple loctite (AKA 222) is low strength. No room for it in my toolbox. No room for red either. Anything I would use red loctite on gets a tack weld or two instead, and I've never welded on my guns...

I've found that blue (242, to be specific) works well for everything I'd use loctite on (from cars to guns). No heat required, just a little more effort and a screwdriver that fits properly.

A little bit goes a long way, so dont run out to buy a bottle. Chances are, the little tube will last you a while.

Edit: in/lb torque wrenches are not cheap. The ones that are, arent worth having. I've heard of some guys putting a little dab of black RTV in one of their rings to help keep a scope from walking, but I've never done it myself.

 

[JDGray]

Blue LT for me also, I've had no luck with purple on some 1911 grip screws. If using the supplied allen wrench, only tighten with the short end in your hand, should be able to get enouogh on it to keep it in place. Were the ring screws loose when you rechecked them?

 

[Uncle Mike]

Coloradokevin, did you notice the tiny indexing notch(es) on the base part the rings(the part that bolts to your receiver) and raised notch(es) on the ring caps of those TPS rings?

If you inadvertently have the caps on the bases in such a way that the notch(es) of the bases do not align with the notch(es) in the rings, the caps will not tighten down enough to grip the scope tube.

Check you correctly indexed the ring caps to the bases.

Also, TPS ring caps will have NO gap on one side on the ring cap, and a small gap on the other side of the ring cap. Contrary to normal rings that would have equal gaps on both sides of the ring cap after properly torquing the caps.

If you have allowed for a gap on both side of the ring cap, the caps are not installed correctly and will not hold your scope.

TPS rings are some of the finest rings made, we use them a lot, and never have had a problem...but, you know what they say, there's always a first time.

OH and BTW...no need for Loctite on the TPS ring caps, they will not shake loose!

Check your, 'ring cap to base' indexing, and that you have bolted the cap down tight to the base on one side, the directions will tell you which side gets bolted down tight, because it is specific.

Oh, and BTW...there is no need for Loctite to be used on TPS rings, cap screws, the screws will not shake loose, make sure you torque the cap screws and base screws to the correct amount of torque.

 

[coloradokevin]

Coloradokevin, did you notice the tiny indexing notch(es) on the base part the rings(the part that bolts to your receiver) and raised notch(es) on the ring caps of those TPS rings?

If you inadvertently have the caps on the bases in such a way that the notch(es) of the bases do not align with the notch(es) in the rings, the caps will not tighten down enough to grip the scope tube.

Check you correctly indexed the ring caps to the bases.

Also, TPS ring caps will have NO gap on one side on the ring cap, and a small gap on the other side of the ring cap. Contrary to normal rings that would have equal gaps on both sides of the ring cap after properly torquing the caps.

If you have allowed for a gap on both side of the ring cap, the caps are not installed correctly and will not hold your scope.

TPS rings are some of the finest rings made, we use them a lot, and never have had a problem...but, you know what they say, there's always a first time.

Mike,

As far as I can tell, the rings have been indexed properly, and tightened in the manner you described. I followed the directions that came with the rings in this regard, and one side of the rings has a gap, while the other side sits flush.

I'm glad to hear that you like these rings, since this is my very first experience with the company! Since you haven't ever needed loctite with these rings yourself, I'm going to guess that my rings weren't tightened to the specified torque level.

Since I didn't have a torque wrench available, I was worried about the possibility of over tightening the rings. In my effort to avoid such problems, I may have under-torqued them.

Do you lap your TPS rings when you install them? I didn't lap mine, as I don't have the tools to do so, and have never tried it in the past.

 

[Uncle Mike]

Do you lap your TPS rings when you install them? I didn't lap mine, as I don't have the tools to do so, and have never tried it in the past.

Generally no, we wont lap rings unless there is no other way around the problem.

Torque the cap screws to 20 INCH pounds for the STEEL rings, and 15 INCH pounds for the ALUMINUM rings, with just a drop of oil on the threads and under the square edge of the screw's head.

Trick...put one drop of BLUE loctite in the saddle of each ring, you can also put one drop in the ring cap, but it really does no better. When you tighten the caps down, the loctite will ooze out, wipe it off with a rag of your choice that has no solvent of any kind on it.

The loctite will solidify and 'take up' any space in the bore of the rings, we'll do this with a special mix of loctite(same blue strength) to kind of 'skim bed' the outside of the scope tube to the inside of the ring bore....works great, and your scope absolutely will not slip in the rings.

 

[Sky]

Uncle Mike great idea about the LT in the saddle!! I have not thought of that....

 

[jerkface11]

I've used fine grit valve grinding compound before.

 

[Welding Rod]

After cracking a lens in a scope, I lap all my rings, at least enough to check if they are reasonable close to aligning.

Don't know if it is a big help in preventing slipping, but a lapping kit is a lot cheaper than a busted scope.

Since I started doing that I also have come to realize how horrible out of synch many ring and mount sets are.

On a high end setup I borrow a Snap On inch pound torque wrench with a big dial for good resolution. I think it goes 0-60 or 0-80. Makes mounting scopes much more pleasurable.

 

[brettrow]

I use blue loctite (I think its called uncle mikes). I use burris plastic ring inserts with burris rings and torque down to 18-24 pounds per what they told me. Never had one walk. I used to lap rings but with the burris inserts you dont have too. They also protect the scope from scratches.