Rifle Scopes ARC M10 and Kahles 525i

[Archangel01]

Ok gents question for you all about Kahles 21in/lb torque recommendation. I planned on dropping this optic into a pair of ARC M10 rings anyone had issues with the 525i or the 624i for that matter running M10 rings?

I'm trying to remember correctly if i read about the M10 rings shortly after their release the the 50-55in/lb torque was causing issues with either just one optic or an across the board issue. I'll admit i have slept since then, and consumed quantities of adult beverages that would cause concern to all healthcare professionals.

I understand that the design of the M10 rings requiring more torque to be applied to a single bolt to hold the optic with the same force as a non hinged mulitiple bolt cap and base type ring, but its late, i cant sleep and the mind is running on autopilot with very very outdated software.

Regardless please help a brother out with the lack of proper memory and google-fu skills.

 

[flyer]

Simply put, if you torque M10s to ARC's instructions and the scope gets damaged, you got a bad scope.

If you torque less, the scope could move in the rings which will mar the tube.

All bets are off if you buy Chinese airsoft knockoffs.

 

[PullMyTrigger]

My 525i, and M10 mediums both arrive today. I’ll be mounting it up tonight or tomorrow morning. I’ll let you know it goes. That being said I have a Vortex Gen 1 Razor 15-20 mounted in M10 lows torqued to 50 in lbs on a different rifle. I removed the scope 2 weeks to push it a little more forward in the rings. Not a mark on the tube, no slipping , looks like it was never mounted.

 

[JWG]

I asked an engineer about cumulative torque. They said 25in-lb on all screws = 25 in-lb of compression. That said, I disagree. I feel that number of fasteners is also as important as amount of torque/tension. My case study is the "watermelon and rubber band game". Each rubber band applies identical tension (roughly), yet they add up and explode the melon. I feel it is the same for rings/screws/scopes. This is why the ARC has a higher torque value.

Just my .02, and I won't stand behind it if I'm wrong.

 

[bjay]

Hmm one thicker rubber band with 20"/lb is same tension as 5 rubber band with 4"/lb coming from each
When they designs these scopes i bet it was tested with 4 screws rings with 15-25max"/lb????
4 screws with 15"/lb torque still 60"/lb tension to the tube

 

[308pirate]

So much fail in this thread

Amateur engineers amuse me

 

[bjay]

So much fail in this thread

Amateur engineers amuse me

Then maybe share what you know or your opinion "mr know it all" your response didnt contribute anything at all

 

[mdmp5]

Not an engineer, but I have very real practical experience with the OP’s question. I have a 624i and M10 rings. I’m usually a less is more guy and I believe I overestimate the force of the torque. I think I torqued the rings to around 20-25 in-lbs because I forgot the specs and may have mixed them up with Seekins. My scope slid so far forward in the rings that the turret body was wedged against the front ring. That was just from recoil from a 6.5.

It needs 50

 

[308pirate]

Then maybe share what you know or your opinion "mr know it all" your response didnt contribute anything at all

I know better than to waste my time when I see shit like this:

I asked an engineer about cumulative torque. They said 25in-lb on all screws = 25 in-lb of compression. That said, I disagree. I feel that number of fasteners is also as important as amount of torque/tension. My case study is the "watermelon and rubber band game". Each rubber band applies identical tension (roughly), yet they add up and explode the melon. I feel it is the same for rings/screws/scopes. This is why the ARC has a higher torque value.

 

[TSean]

Ok gents question for you all about Kahles 21in/lb torque recommendation. I planned on dropping this optic into a pair of ARC M10 rings anyone had issues with the 525i or the 624i for that matter running M10 rings?

I'm trying to remember correctly if i read about the M10 rings shortly after their release the the 50-55in/lb torque was causing issues with either just one optic or an across the board issue. I'll admit i have slept since then, and consumed quantities of adult beverages that would cause concern to all healthcare professionals.

I understand that the design of the M10 rings requiring more torque to be applied to a single bolt to hold the optic with the same force as a non hinged mulitiple bolt cap and base type ring, but its late, i cant sleep and the mind is running on autopilot with very very outdated software.

Regardless please help a brother out with the lack of proper memory and google-fu skills.

Hi Archangel01,

To answer your question, you will be 100% good to go with the ARC M10 rings torqued to spec on a Kahles. Some instructions say 55 in-lbs, some newer ones say 65 in-lbs, but I have always just stuck with the 55 in-lbs (base and cap) and had zero problems with quality scopes (S&B, NF, Kahles, TT, Vortex AMG, etc.) mounted to everything from .223 to .338NM.

To your specific concern with Kahles, I have my 624i in ARC rings torqued to 55in-lbs and the combo is 100% good to go. Further, unless I am mistaken, (and not to speak for anyone else), many of the competitive shooters for Team Area 419 and Team Short Action Customs (among others I am sure) have been using that combo (Kahles and ARC rings) successfully, and I am sure they plan to continue with the new 525i. Go forward without hesitation. You have picked a great scope and ring combo, I hope they serve you well for a long time! Have a good one!

-TSean

 

[scudzuki]

I asked an engineer about cumulative torque. They said 25in-lb on all screws = 25 in-lb of compression. That said, I disagree. I feel that number of fasteners is also as important as amount of torque/tension. My case study is the "watermelon and rubber band game". Each rubber band applies identical tension (roughly), yet they add up and explode the melon. I feel it is the same for rings/screws/scopes. This is why the ARC has a higher torque value.

Just my .02, and I won't stand behind it if I'm wrong.

The M10 ring clamp screw torque requirement has to do with their being a single screw for each "band" AND the fact that one end of each of the moving elements is a hinge. It's a complex thing to calculate. I saw recommended torque value for the M! clamp much higher initially (IIRC 70 in/lbs.) before it was lowered to the current recommendation of 50 in/lbs.

The watermelon explodes because its skin is relatively flexible and the accumulated (additive) force of the rubber bands leads to an equally distributed internal pressure that breaches the skin in one region.
The structure of a scope tube is not supported by the air pressure inside.
The scope tube at any point along its length has the same structural rigidity because of the compressive strength of the material (aluminum) it's made from and the wall thickness of said aluminum.
Increasing the number of clamping locations along the length of the scope main tube has a linear effect on the resistance of the scope tube to move longitudinally.
Your understanding of the material sciences could use some refinement.