The linked video is a discussion of lubricating the bases of scope mounts when mounting them on Picatinny/Weaver type rails. The practice is known as “wet” mounting, and according to the individual being interviewed, it can help prevent sighting shifts if the scope is subjected to side impact.

Although the video doesn’t go into a technical discussion of why the practice helps, I believe that oil or grease on the scope mount base (not inside the rings!) helps ensure that the mount settles into its final position when it’s tightened down. If not lubed, friction can prevent that, and if there is impact against the scope or mount later, that friction is overcome and the mount can shift with respect to the mounting rail on the rifle.

Is it always necessary? Probably not, but in addition to making sense in theory, it’s quick and easy and is reportedly being adopted by many precision rifle shooters.

https://www.youtube.com/watch?v=kL5LvXd14Yc&t=3s

NOTE that this is about lubing the contact surfaces between the scope mount base and the mounting rail on the rifle. Do not put lube on the inside of the ring surfaces that contact the scope. In fact, the man in the video recommends the old trick of using powdered rosin on those surfaces to help prevent the scope from sliding in the rings.

Why not inside the rings?

Years ago- circa ‘93 I had a chance to see the inner workings of the Marine Corps precision marksmanship unit in Quantico. I watched as the Marines put together M-16’s, M-14’s, 1911’s, and the Marine Corps Sniper Rifles, the M-40’s.

I watched as the Armorers took a small gob of grease and coated where the Rings contact the receiver and the inside of the Rings where they contact the scope. They told me that it:
Made for a better fit between the Rings and Scope
Waterproof- you know the different climates the weapon is going to.
Rust proof- difference in metals of the Rings and Scope can lead to oxidation and rust, even very minor- would still lead to a change in accuracy.
It also helps with the Scope not sliding too much when initially mounting it.

This may be an old “wives tale”, or something of legends. I don’t know. Im not an Armorer, nor that great of a shot on a long gun.

the gun shop where I used to spend a lot of money and time, whenever they would mount a scope they would lube the rings in the manner described, always said it was as a precaution and didn't hurt anything and this was in dry CA. humidity was not an issue.

They catered to guys who could afford hunting on any continent as well as guys who bought quite a few very expensive precision rifles and premium glass Hensoldt, Schmidt & Bender, Nightforce, Swarovski, etc. rifles like Accuracy International, Blaser R8 etc and had guys shipping in rifles built at places like hill country rifles and other custom houses.

Well, another thing I’d never heard of was lubing the inside of scope rings.

As I mentioned, applying powdered rosin to those surfaces has long been recommended to help prevent the scope from slipping under recoil, and that’s just the opposite of reducing friction. But beliefs change based on new findings, so all I can say is that’s a new one on me and unlike lubing the mount(s), I’ll have to think about it for a bit to understand its benefits.

They greased all the metal-to-metal contact points.
Scope to the rings.
Rings to the receiver.

Now, probably the rings to the picatinny base, and the base to the receiver.
Granted, it's been 30+ years, and things may have changed. I've also heard of other armorers doing it, but that was years ago.
Does it help or hurt? I wouldn't know, because my experience with those weapon systems are rather limited, and my skill level wouldn't be able to determine any difference.

I will say I did it when I mounted my Vortex to my Ruger 10/22 Takedown! So watch out because those bad-mamma-jammas rank right up there with an Accuracy International, McMillans, Sakos and Havaks!

I've mounted my share of scopes on precision rifles, both ARs and bolt actions. I've watched some very experienced 'smiths & shooters mount scopes. Never have I seen anyone use the wet mounting method. Never have I heard of it before.

I've had my rifles/scoped bumped more than I care to admit. I've seen quite a few others bumped. Shoot PRS or 3-gun and it happens all the time.

I'm fine with dry mounting scopes. When using quality components, when the bolts/screws are torqued to spec, the rifle/scope systems hold zero just fine.

Maybe wet mounting makes a difference, maybe it doesn't. There are many devices & techniques on the web that people swear by -- some are proven by double-blind testing, some are proven by "well, it works for me."

https://youtube.com/shorts/1Ah...?si=boWdG5dBi1y0epwC

Here’s a short video that explains wet mounting the rings to the rail

Well that's a new one for me!

quote:

Originally posted by CPD SIG:
Here’s a short video that explains wet mounting the rings to the rail

Thanks for that. I watched that guy’s video about the problem with trying to level a scope by checking the orientation of the scope mount before tightening it to the receiver rail. I find the … self-assurance (for lack of a different term) of presentations like his somewhat annoying, but that earlier video did prompt me to reevaluate how I mount my scopes. I believe the way I was doing it before was probably more than adequate for my purposes, but I did change some things.
And now I’ll give him credit for admitting that the “wet” mounting method seems to eliminate the concerns he expressed before.

Regarding how things are done in the military, there was a saying that there were three ways of doing things: the right way, the wrong way, and the Army way. Right or wrong, we did things the Army way, and I know from personal experience that it wasn’t always the right way. I have found blatant factual errors in a military sniper training manual and from time to time I learn of other things military personnel are being taught to this day that are simply wrong. I therefore keep my skepticism filters in place regardless of the source of any information.

I dunno, I always use a very light swipe of EEZOX on those surfaces anyway.
Never had any problems but I can't necessary the credit to "wetness".
It was pretty thin coat as it were.

And now a dissenting opinion:

https://www.youtube.com/watch?v=zxP-zzIC6aU

Would something like a Larue VFZ mount be immune to the symptoms that wet mounting is supposed to address?

I don’t know that I fully understand the mounting mechanism of the VFZ, but its contact surface with a base is fairly small, and that would reduce the friction between the mating surfaces. And reducing that friction is the reason for the “wet” process.
But whether there’s something else about how the VFZ contacts the base, I don’t know, and I’d be interested in other opinions.

VFZ doesn't use cross-bolts. The clamping force is exerted in a different way. I thought that may make a difference.

Unless you never plan on using oil on your rifle, it's going to get under the rings anyway. The notion that you are going to make the scope prone to slip by oiling during installation seems a bit silly. On the rail may help a bit with seating if the rail/rings aren't the top of the line, but who knows? The high end rings and bases we have now bear little resemblance to what we dealt with 40 years ago when nothing lined up and lapping rods were still a thing.

"Dry mounting" isn't going to let "friction" resist the force that you're tightening things down with. "Wet mounting" is unnecessary, but won't hurt anything either.

Does anyone bother lapping scope rings anymore? No. Because machining precision and materials today are much better.

I file a lot of things under the same category as vacuum tube amplifiers. Unnecessary, and the people who enjoy it shouldn't act like they know something the rest of us don't. It's a preference only.

I do something I don't see many others do. I take a paint pen and put a dot between the scope and ring. It'll tell you if it ever moves. I also use grease instead of loctite in the threads of all kinds of things. All these little tricks work for me.

Okay, I understand the corrosion issues, dissimilar metals between the rings and the scope tube. But wouldn’t over time the lubricant leech from the mounting? Would something like Birchwood Casey”s Barricade be an alternative to oil or grease?