Scope Ring Torque

[Steve K]

I have a Leupold scope, Mark AR MOD-1, mounted on a dedicated 22 AR upper. I am using a Nikon Tactical 2-piece mount. When I change power going from 4X to 2X the point of impact changes. I called Leupold and the tech advised to check the inch pound setting. He explained the wrong pressure can change the POI. However, he was not able to tell me what inch pound torque to use and I should call Nikon. I did that and the tech was useless. So I am asking you if you can help figure this out.
Thanks in advance.

 

[1Merlin]

Sounds like a lot of tech BS to me. Changing poa should not happen during power changes. Maybe if the rings are actually deforming the tube but that's very unlikely.

 

[Clancy]

I don’t think that’s it either but 18-20 inch lbs (dry torque) will work on any scope I’ve ever seen.

 

[skeeljc]

I use Vortex Precision Matched rings. They are HD and do not leave any marks. I torque the ring caps to 25 in-lbs.

 

[MUP]

Seems fishy to me as well. Torque setting shouldn't affect poi after the fact. That said I generally torque rings to 16 in/lbs and bases to 20 in/lbs, that is if I can't find manufacturer recommend settings.

 

[WyleWD]

I have a Leupold scope, Mark AR MOD-1, mounted on a dedicated 22 AR upper. I am using a Nikon Tactical 2-piece mount. When I change power going from 4X to 2X the point of impact changes. I called Leupold and the tech advised to check the inch pound setting. He explained the wrong pressure can change the POI. However, he was not able to tell me what inch pound torque to use and I should call Nikon. I did that and the tech was useless. So I am asking you if you can help figure this out.
Thanks in advance.

I agree with the other posters that it is unlikely that the rings are causing the problem.

A few years back I had another brand 4-12x scope that would move POI around 4-6" at 100yds just by changing magnification from 4-12x, and anywhere in between. When bore sighting you could watch the reticle move up and to the left. I sent the scope back to the manufacturer explaining the issue. In a couple weeks I had a new scope, and a week later a letter from them apologizing for my troubles. JMHO, but Leupold should do the same for you. WD

 

[HTSmith]

According to my friend who's a customer service manager for a scope company, yes excess torque can impact adjustments. He recommends 17-20 inch lb generally. Just passing on what I've heard from what I believe is very good source.

 

[grauhanen]

Apparently Nikon no longer makes this product and offers no relevant manufacturer's specs online.

Insufficient torque may cause the problem described, but too much can harm the scope. Usually 25 -30 inch pounds of torque on the base screws are good, with about 18 inch pounds on the rings. Make sure that a good torque screwdriver is used.

It's worth noting that other problems with the scope may result in changing the POI with magnification changes.

 

[Larryh128]

IMHO if this is an issue with torque on the screws I would be looking to see if the rings were in alignment.

 

[F Class John]

My understanding in talking with them in the past (and having taken a tour of their place) is that Leupold can typically handle 20 inch pounds of torque as a safe number. I personally go 25 in/lb on my Mark5HD and I'm using Leupold rings on it.

I can also tell you that they (and most other companies) are reluctant to quote numbers when it's not 100% their scope AND rings. Like any manufacturer, they've been burned when thinking other manufacturers would allow the same torque settings. Not all scopes (and rings and other components) are made the same. In this case it’s all in the design.

I also know some other companies only allow 15-18 inch pounds and I’ve seen people crush maintubes which will affect POI. Yes. Crushing the maintube can cause POI. It doesn't mean it will, it just means it can.

Placement of the rings makes a difference too. I've seen guys put the rings too close to the turrets or in some cases to the objective and/or eyepiece and it can have a detrimental effect as well on repeatability and POI.

Also be aware that no torque wrench is exactly what it claims so make sure you work safely within the limits of whatever tool you have. I've seem some that are as low as 2% and most cheaper ones are more like 7-10%.

 

[dgeesaman]

I can also tell you that they (and most other companies) are reluctant to quote numbers when it's not 100% their scope AND rings. Like any manufacturer, they've been burned when thinking other manufacturers would allow the same torque settings. Not all scopes (and rings and other components) are made the same. In this case it’s all in the design.

Naturally. Scopes are hollow tubes and we wont buy overly heavy ones. So the scope manufacturers just have to hope you’ll buy quality rings and install them properly.

I’m sure that cheap rings or a wavy rail or a burr of metal somewhere can warp a main tube. Not much they can do about it.

David