Scope mounting loctite or not?

[ljalberta]

I de-grease the screws and clean them with cloth so as to remove gunk from the threads. I let them dry so they are spotless. I then apply a light sheen of oil, and evenly and properly torque down the ring cap screws in X pattern by angle…

Out of curiosity. How many rounds are you shooting a year, and how often do you check torque or retorque. In my experience, oil on the screws and lots of use is a recipe for a loose screw. I’ve come to like the loctite and not worry about it.

 

[JohnDough]

Out of curiosity. How many rounds are you shooting a year, and how often do you check torque or retorque. In my experience, oil on the screws and lots of use is a recipe for a loose screw. I’ve come to like the loctite and not worry about it.

Not a whole ton, honestly. I never re-check torque because you will always end up adding more with most torque wrenches. I do witness mark. Nothing's ever moved, but again, I would not call myself high round count usage.

 

[SDHNTR]

So, I did a deep dive on this years ago, asking a ton of industry professionals from the .mil side of the house what they did and why.

Nightforce: Sure, Blue loctite is fine. Torque to 25 in-lb like it says. We don't know if engineering said wet or dry or whatever, but we don't care, this thing is a hoss!--Paraphrased, regarding Unimount and NXS 1-4 at the time. (I did this, and when I removed the scope after years of use, ZERO ring marks, also it tracked true and was fine.)

Vortex: Loctite is bad in that it increases compression on the tubes. Reduce torque by 25% or don't use it. We have had scopes damaged by the use of loctite. (I have never owned Vortex)

Hakan Spuhr: We ship our screws waxed. People who strip this off and torque dry can have issues. If you clean them with acetone, alcohol, etc then use oil or loctite. DO NOT torque a dry screw for my mount or any other mount, especially if the base metal is aluminum, as most of the torque goes into drag/friction and not clamping. (I have never owned a Spuhr mount, but have spoken with Hakan on this very topic.)

KAC: A small bit of oil, just a sheen, wiped on the threads. Clean and sheen. Not dripping, not dry. (I have never owned a KAC scope mount).

Leupold: We will ship you screws with nylok patches on them with our ISMS mounts so you can stop quibbling about it. Torque it to 28 in-lb, fam! (Although when I did this, I got flakes of black stuff in the tube of my MK6, which I am suspicious could be flaking ano from tube compression. I have nothing to back that with, and Leupold cleaned it out in 3-4 weeks for me, saying nothing about the matter).

Geissele: The screws come lightly oiled and are meant to be de-greased with 222 added, or installed as they come, with light machine oil, to 18 in-lb. (When I installed a K16i in a G SuperPrecision mount using these values, it mocked up with several thousandths clearance on both sides dry at 18 in-lb), then I added loctite and the ring halves did indeed go solid at about 15-16 in-lb. as measured by feeler gauges. K16i's have thing, soft tubes, though, but this IS personal proof witnessed that Loctite does allow for increased compression vs dry, clean threads, and whether this is a good or bad thing depends on the equipment used.)

Reptilia: We recommend dry, clean screws. Regarding their AUS mounts. That said, the instructions also list 222 as "optional, not needed" and no separate torque spec is offered for if it IS used, as Vortex does (11 vs 18 in-lb) on the Gen 3 razor. I have further inquired for clarification.

That said...what do I do?

I de-grease the screws and clean them with cloth so as to remove gunk from the threads. I let them dry so they are spotless. I then apply a light sheen of oil, and evenly and properly torque down the ring cap screws in X pattern by angle, so that clamping forces/compression remains equal. I will end up with no worse than a 0.002" delta between all points on the rings on either side. I also make sure nothing "goes solid", because THIS is what will cause slippage (as well as under torque). The screws have constant tension on them from both a little bit of thread stretch, and mainly scope tube compression rebound. It makes the threads behave like Helicoils, and this is why you do not need to use a thread locker. The slight sheen of oil is important so that all fasteners have equal compression from equal axial force. That's all torque measured with your wrench is, is the measure of axial force required to overcome drag. I do make sure that my scopes have overlap with the mount specs. For example, I use Nightforce scopes and Reptilia AUS mounts. Reptilia says 15 in-lb, Nightforce says 25 in-lb max (they used to say 15, but changed it a couple decades ago because people complained "WiLl It HolD!?" and they tested, determined 25 was safe for their product, and changed the recommendation to stop the questions, lol! No scope ever slipped in their testing even on .50 BMG at 15 in-lb. Another thing I will do is use acetone to chemically de-grease the mounting surface of the scope tube and inner rings. I leave this as such, bone dry. I will also lightly oil the 1913 section of rail that the mount clamps to, on my AR's. This comes from conversations with Hakan Spuhr, which he has publicly stated as well and you can Google in your free time.

Nightforce for the win.

 

[JohnDough]

This does not seem to imply that threadlocker is necessary, but it does cast considerable doubt on claims of overtorquing.

 

[JohnDough]

Do you Loctite the action screws? How about spark plugs? No, because it’s not needed. Loctite whatever you want, but it’s as silly as bead lock rims to drive down forest service roads.

Nothing on the rifle is as easy to re torque as the ring screws - this concept is ridiculously easy to test for yourself by simply checking the ring torque on every rifle you own to see if they have loosened up. They never do - it’s not a thing.

Checking and rechecking with most torque wrenches can over a few cycles cause the screws to become tighter than indicated. A witness mark is a better alternative, and should be used whether a locking compound is, or not.

 

[Eagleman]

You ever hear of James Eagleman the ex special forces sniper who runs Barbour Creek Shooting Academy? Guess what seen him mount scopes without loctite on the rings and guess what. Those rifles are fired 1000's of times a year in his classes. He recently swapped a barrel on one with over 4000 round on it. Still hitting original poa with no change in poi just groups were opening up because barrel was toast. Now tell me he doesn't know what he's doing or talking about. Just because the way you do it works for you doesn't mean that's the only way to do it.

sorry late reply just found the forum to clarify not ex special forces; I am a retired Army sniper and graduate of 5th Special Forces Sniper course! don't want to have bad info out there. I use vortex rings and never use Loctite on them with 6 school guns and literally thousands of rounds through them never an issue

 

[Appalachain Hunter 304]

I use blue Loctite while mounting scope bases and rings.

 

[4th_point]

sorry late reply just found the forum to clarify not ex special forces; I am a retired Army sniper and graduate of 5th Special Forces Sniper course! don't want to have bad info out there. I use vortex rings and never use Loctite on them with 6 school guns and literally thousands of rounds through them never an issue

Glad you're here, James. I appreciate the information you have shared over the years.

Regarding the Vortex rings, they appear to be the ones made by Seekins?

Some people here claim loss of zero with Seekins rings. Maybe a few that broke - low height, if I recall correctly.

Have you seen any issues with the Vortex/Seekins, at all?

I've used the Seekins a bunch and never had issues. I don't use threadlocker on ring caps or halves.

Jason

 

[Eagleman]

never tried them my friend seekins

no issues with vortex

 

[keeper_]

I've used loctite purple with a little witness marks on the small screws that I'm paranoid about, scope rings and plate mounts

 

[Macintosh]

@4th_point @eaglemountainman i have been told dozens of times over the years that vortex PMR rings are manufactured by seekins. I have both, afaict they are precisely the same thing as the seekins rings, other than logo. So I believe this is true.

 

[86indy]

I've used loctite purple with a little witness marks on the small screws that I'm paranoid about, scope rings and plate mounts

Ditto. The lightest grade thread locker, actually use a torque wrench and index screws with a paint pen.

Make sure threads are clean and free of oil with rubbing alcohol.


Sent from my iPhone using Tapatalk

 

[AO_Hunter_2110]

I know it was probaly mentioned somewhere in this thread. I understand people being spilt of using loctine on the screws that clamp the tube of the scope, but what about the bases of the scope rings to a pic rail? I have always used scope rings that screw to the action and I always use loctite for the base screws, but I will be mounting my first pic rail scope rings. I will be using loctite for the rail screws to the action, but on the fence of using loctite for the scres that hold the base of the rings to the rail.

 

[JohnDough]

I like to keep up with this thread. I recently bought my first real Vortex (I had previously owned some Strike Eagles purchased as gifts for new shooters on low use guns.). I called Vortex and Reptilia. Reptilia is who made the mount, and Vortex the optic, for Project Hunter. Likely one of the most exhaustive optic and mount contracts with regard to testing. Several hundred thousand rounds of real and machine approximated 7.62 rounds down range from scar H were used as vetting.

So I reached out to Reptilia. They advised me to use 15 inch pounds of torque with their mounts, which was specified dry both in their comms with me, and in their product instructions. The screws and mounts are 100% bone dry, chemically decreased, upon arrival. They specified 0 oil, 0 loctite. They were very clear in their instructions both when I reached out, and when I read the included instructions.

I then reached out to Vortex, who made the optic. They took a few days to respond to me as they discussed this with their team. They finally replied that for Project Hunter, they tested of course the contract Reptilia mounts and their optic, installed as per instructions as they arrived---dry, no oil. No loctite.

During extensive live and simulated testing, no scopes moved in Reptilia mounts, and no ring cap screws became loose.

Since I am using tried and tested combo of vortex scope and reptilia mount, I have used 16 inch pounds (what's 1 more? Makes sure if my wrench is on the shy side its still minimum spec, and still gives 2 inch pounds leeway on the big side per vortex 15-18 instructions), dry, and nothing else.

Things I noted: the screws moved until the wrench clicked over. Its been my experience that when inconsistent clamping is happening, near the end of the sequence, the screws simply stop moving as tq is applied and then soon the wrench clicks. These spun right about up to the moment the wrench clicked. Also, the ring gaps from front to back are within 0.002". This is the same as my loctited nightforce projects have been.

I really like using optics combos that were developed in conjunction with one another. Both companies/or the same, for nightforce etc, have tested amd engineered the torque specs and compatibility and tested for validity on Shaker tables and with live fire, to the specs of the military purchasers involved. This supersedes the backyard tests on forums like this and others no matter how well done, by virtue of budget and sample size alone, as very few people have a Shaker table that can accurately reproduce scar h recoil, or the budget to run $50k worth of optics and mounts on said table, plus similar live fire, etc. Standing on the shoulders of the companies involved is cheaper and easier by far.

As to the scope and so forth, I am very pleased.







Interestingly, although the reticle is as level as I think possible, the laser engravings are a bit wonky.

 

[atmat]

I like to keep up with this thread. I recently bought my first real Vortex (I had previously owned some Strike Eagles purchased as gifts for new shooters on low use guns.). I called Vortex and Reptilia. Reptilia is who made the mount, and Vortex the optic, for Project Hunter. Likely one of the most exhaustive optic and mount contracts with regard to testing. Several hundred thousand rounds of real and machine approximated 7.62 rounds down range from scar H were used as vetting.

So I reached out to Reptilia. They advised me to use 15 inch pounds of torque with their mounts, which was specified dry both in their comms with me, and in their product instructions. The screws and mounts are 100% bone dry, chemically decreased, upon arrival. They specified 0 oil, 0 loctite. They were very clear in their instructions both when I reached out, and when I read the included instructions.

I then reached out to Vortex, who made the optic. They took a few days to respond to me as they discussed this with their team. They finally replied that for Project Hunter, they tested of course the contract Reptilia mounts and their optic, installed as per instructions as they arrived---dry, no oil. No loctite.

During extensive live and simulated testing, no scopes moved in Reptilia mounts, and no ring cap screws became loose.

Since I am using tried and tested combo of vortex scope and reptilia mount, I have used 16 inch pounds (what's 1 more? Makes sure if my wrench is on the shy side its still minimum spec, and still gives 2 inch pounds leeway on the big side per vortex 15-18 instructions), dry, and nothing else.

Things I noted: the screws moved until the wrench clicked over. Its been my experience that when inconsistent clamping is happening, near the end of the sequence, the screws simply stop moving as tq is applied and then soon the wrench clicks. These spun right about up to the moment the wrench clicked. Also, the ring gaps from front to back are within 0.002". This is the same as my loctited nightforce projects have been.

I really like using optics combos that were developed in conjunction with one another. Both companies/or the same, for nightforce etc, have tested amd engineered the torque specs and compatibility and tested for validity on Shaker tables and with live fire, to the specs of the military purchasers involved. This supersedes the backyard tests on forums like this and others no matter how well done, by virtue of budget and sample size alone, as very few people have a Shaker table that can accurately reproduce scar h recoil, or the budget to run $50k worth of optics and mounts on said table, plus similar live fire, etc. Standing on the shoulders of the companies involved is cheaper and easier by far.

As to the scope and so forth, I am very pleased.

View attachment 1005534
View attachment 1005535
View attachment 1005536
View attachment 1005537


Interestingly, although the reticle is as level as I think possible, the laser engravings are a bit wonky.

View attachment 1005538
View attachment 1005539

Oh boy.

 

[Castle Rock]

Yep

 

[DaveT1]

Just wondering if using blue loctite on the ring bases is necessary? Was told recently by a gunsmith it's not recommended.

I use purple locktite.

 

[JohnDough]

I have experienced two things now that shape my views.



The first was almost a decade ago. I was setting up a K16i in a Geissele Super Precision mount. I torqued the ring caps down dry, and a feeler gauge averaged around 0.003-4 all around, and I gently un-torqued the front ring cap, and loctited the screws, and torqued back to 16 in-lb. I did the same with the rear. They had gone solid except for 0.001" or so on one side, as I recall. Geissele verified that the mount was in spec. Kahles verified that the scope was in spec. I was using a Wheeler Fat Wrench.



Now, I got curious again today, and bought a 34mm x 1.5mm thick 304S tube. I got some Monstrum 7075 rings (cheap for this project).



I torqued a ring on chemically de-greased. On the left side, it gauged 0.013" with feeler gauges between the ring-halves at 15 in-lb. Initially, it was 0.0285".



The right side, I did the same. It measured 0.017", and initially was 0.0285".



I then loosened the upper left screw, and re-torqued to 15in-lb. I repeated this in sequence all around. The measurements I got once re-torqued for the left side were 0.013", 0.013", 0.013". For the right, 0.017", 0.018", 0.018".

I then did the same, but applied loctite to the screw before retorquing. Just wetted the last 3-4 threads. None under the screw cap.



The left measured 0.012, and the right, 0.016".



I immediately loosened the screws, and set the Vortex torque wrench to 12 in-lb, and re-did this. The left measured 0.013", and the right, 0.018".



In short, the K factor of loctite does allow more torque to be applied to the optic tube than "dry" torque. In this case, when we model the clamping force delta using the 8-40 screw size steel into aluminum 7075 anodize (0.47 coefficient), and 15 inch pounds, we get a clamping force of 194lb-f of clamping force. This based on our measurement of the same compression at 12 in-lb indicates that at 15 in-lb using loctite, we would receive roughly 240 pounds of clamping force. Of note, the k-factor I observed with loctite appears to be 0.2, working backwards, which tracks with published data more or less.

Keep in mind these forces are multiplied by 4 (or 6) screws, as such you can end up with 200 pounds more clamping force on your optic when using loctite, vs. what is intended.



So lets say we clamp our Vortex scope to 18 in-lb, the most they recommend. Dry, that is 233 pounds per screw of clamping force, or 932 pounds per ring. If we apply loctite, it becomes 291 pounds of clamping force, or 1164 pounds per ring, or 232 pounds more compression than design intent.



Ultimately, we are left with both a calculator and real-world observable events which show us that yes, loctite does meaningfully alter the compression of scope rings by potentially hundreds of pounds in compression force.



Always follow the instructions of the manufacturers whose products you are using.