I'm pretty sure I've read on here that the torque ARC recommends for its M10 rings is too high, but I can't seem find those posts. For the guys using those rings, what did you torque them too? I'll be using their 30mm rings on a Vortex AMG, if that makes any difference.
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Rifle Scopes ARC M10 Rings - Torque?
- Thread starter atxhorn4425
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I torqued the M10's on my AIAT in 308 using a Gen II Razor down to 45 in/lbs and haven't had any issues. I would go with the spec'd 55 in/lbs though on a light rifle in a magnum caliber though.
I would use 45 in/lbs in your situation but that is just my opinion.
I would use 45 in/lbs in your situation but that is just my opinion.
I think I remember a few years back Big Jim Fish did a review on a set where he was worried about the torque recomended so he tried them out on his cheapest Chineese junk scope first and crushed it. Then he called Ted to clarify the torque and was told that he was to stupid to be allowed to reproduce, that ARC rings were designed to be used with rugged high quality scopes, and Approach the setting with caution. I use 40 inlbs on my .260, and it seems to work ok.
On my .308 I torqued action screws, cross mount bolts and rings to 55 inch pounds. Keep it simple. I have moved the scope forward and back a few times with no marks what so ever. I'll do the same on my 6.5 creedmoor once the new scope comes in. Just my method of madness.
Awesome, thanks guys. Actually just got a PM from a Vortex employee who said they bought some ARC rings recently for testing out so they could answer this exact question, and that they didn't have any issues with using the recommended torque settings. Vortex customer service FTW as usual.
This is going on a 6.5 Creedmoor so I'll probably just use about 45 in/lbs, but sounds like I could go up to the full 55 in/lbs if needed.
This is going on a 6.5 Creedmoor so I'll probably just use about 45 in/lbs, but sounds like I could go up to the full 55 in/lbs if needed.
I used the 55 inch/lbs with a 5-20 Ultra Short and a gen 2 razor and an AMG so don't worry about it. The reason that the torque setting is so high is because there's only 1 screw and because it's placed at the top it had a different effect compared to a traditional design.
Better to have it and not need it, than to not have it and say oh shit.....
Better to have it and not need it, than to not have it and say oh shit.....
Interested in opinions on this as well. Just threw a set of M10's on my 308 this week and started out at 20 in/lb... I'm thinking that may have been to low based on how it shot when trying to rezero it. Increased it up to 45 in/lb and will see how it does next range trip.
For your education: http://www.engineersedge.com/calcula...orque_calc.htm
Total clamping force is then multiplied by number of bolts. Smaller diameter bolts generate more clamping force, less surface area = less force lost to friction.
Ted recommends small bit of oil under head as this is primary friction area. You can google more and learn all you'd like, but this is the basic principle.
I'd assume the force would then be divided by ring surface area to come up with PSI which most tubes are rated in PSI for collapse.
Total clamping force is then multiplied by number of bolts. Smaller diameter bolts generate more clamping force, less surface area = less force lost to friction.
Ted recommends small bit of oil under head as this is primary friction area. You can google more and learn all you'd like, but this is the basic principle.
I'd assume the force would then be divided by ring surface area to come up with PSI which most tubes are rated in PSI for collapse.
I split the difference between the numbers posted here and go 50 in/lbs. They are the only rings I use on my rifles and they have NEVER left a mark on a scope.
Conrad, thanks for the tip about a little oil/grease under the head, hadn't heard that before but will start making that SOP from this point forward.
Conrad, thanks for the tip about a little oil/grease under the head, hadn't heard that before but will start making that SOP from this point forward.
No problem, there is "wet" and "dry" torque. Most values represent wet torque but you can see there isn't a large difference in coefficients of friction, and so with quality rings we are all probably getting all the clamping force we need regardless.
I have gotten a little nervous about Vortex's low torque specs, and tried to back calculate PSI for collapse, but I don't know all the specs on their tube, so knowing that they tested ARC's themselves is really awesome and gives some peace of mind!
I have gotten a little nervous about Vortex's low torque specs, and tried to back calculate PSI for collapse, but I don't know all the specs on their tube, so knowing that they tested ARC's themselves is really awesome and gives some peace of mind!
55 inch lbs on base and scope in Athlon Steiner Minox. Never a single scratch and never a scent of a slip. If ted didn't want it at 55 inch lbs then he shouldn't have posted that that's the spec. So I trust Ted. He designed and engineered them. Don't much care if a guy feels uneasy about going another 16th. Ted word is law cause he invented em.
Thanks guys. I went with 50 in/lbs since it's just a 6.5 Creedmoor, but consensus seems to be up to 55 in/lbs is no problem. Great looking rings and great design, easiest install I've done.
Yep, 20 in/lb was definitely too low for a 308. No more issues once I increased the torque to 45 in/lb.
arc M10
both rail & scope clamp screws
50-55 inch pounds
I've never had an issue at 45 personally which is what I run them at, always use a torque wrench
both rail & scope clamp screws
50-55 inch pounds
I've never had an issue at 45 personally which is what I run them at, always use a torque wrench
Ok, I've been using ARC M10 rings for a while now on many different scopes. I have an IOR 3.5-18x50 (yeah yeah, I know...) In 35mm ARC rings. IOR says to torque scope rings to like 13ish inch lbs, and then ARC's #'s are significantly higher. The scope has been great so far with zero issues and I just want to see if anybody has some insight on this particular combo. Do I go with IOR's torque specs, or ARC's, or do I just split the difference somewhere? Just want to make sure I don't damage the scope tube and have to go through the whole warranty/scope repair debacle. Any info would be greatly appreciated!
13 inch pounds sounds fairly weak, maybe for a rim fire lol.... I don't know how good the quality is on the IOR tube, but I would say you need to be at least around the 45 inch pound mark with the M10's cause they only have the one screw..
The ARC design is different from standard #15 or #25 small screws x4 or x6
they've been tested by scope engineers and they will not damage the scope at pressures significantly higher than the recommended poundage
Go for 35 in# and see if it slips, if not, try 40#
they've been tested by scope engineers and they will not damage the scope at pressures significantly higher than the recommended poundage
Go for 35 in# and see if it slips, if not, try 40#
I plan to use M10 rings on a Sightron Slll 8x32x56. Sightron customer service said I would crush the scope, but that was customer service and not an engineer. Are the Sightrons sturdy enough to go the 50 or 55 inch/pounds reccomended by ARC? I don't want to kill my scope. Thanks.
I literally just finished installing my 3 and 4th set. I have been using a Fat Wrench and using 55 in pounds on the base screw and 50 on the top screw. Zero issues on the first 2 sets which I got curious about after reading some posts. Used them on a T5Xi and a Mark 5 with out so much as a scuff on the finish.
Same here I just followed the torque spec’s specified in the instructions and I’ve had no issues. Getting ready to order more for a new build, there great rings in my opinion.
Something I do, whether it's really recommended or not... I identify the thread size and reference the max torque spec for that thread. I'll also compare torque from the mount manufacturer's recommendation for ring halves scope and the scope manufacturer's recommendation. If they differ, then I take a look at the materials involved. Some scope bodies may be thicker than others, so getting away with a higher torque value isn't as bad... but you'd be surprised how much clamping force four #10-32 screws at 18in/lb actually has. Most people over-torque anyway. I'm meticulous with torque values. Cross-bolts always get a 5fl/lb value in my book.
But we are all meticulous with our own stuff... this is just my $0.02
But we are all meticulous with our own stuff... this is just my $0.02
I now make sure to always torque my ARCs to 55in/lbs and it’s never been a problem.. This happened to me: I zero’ed my rifle and went to a local small match my gun shop put on for us, suddenly I wasn’t hitting anything and had no clue what was going.. Later that evening I discovered my scope had slid in my rings. I had accidentally torqued them to 22in/lbs instead of 55in/lbs using the Borka kit- I was shooting a .308.. I would caution against torquing them too light..
Yea, that pretty much captures the gist of it. I ended up using 35 inch lbs with lubed fastners (you should always use lube) and did not have things come loose. I believe that was on a bare muzzle 10lb .308. I'm not sure that 35lbs is the ticket number but I do think it is a good place to start and I am acquainted with the 55inch/lbs crushing some scopes that were much more expensive than the $600 one I used. Clearly, some of the really heavy tube scopes out there can take it but I don't think it is a good idea or at all necessary.
I have a set of ARC M10 rings on my 300 winmag. They were torqued to 35 inlbs and I thought that would be strong enough without crushing my Leupold Mark V.
I had problems with zero retention. Scope was sliding rearward in the rings. I torqued to ARC's recommended 50 to 55 inlbs.
No more problems. No crushed scope. Just my experience.
I had problems with zero retention. Scope was sliding rearward in the rings. I torqued to ARC's recommended 50 to 55 inlbs.
No more problems. No crushed scope. Just my experience.
I have a set coming for my 300 prc. I have a vortex strike Eagle 5-25x56 for it. Will 55 in/lbs be ok on that scope? It says 18 on the tag around the scope. This is my first set of ARC’s. I’ve always used seekins rings.
Yes. 55in/lb is the torque value to use.
Basically: Torque = nut factor * bolt diameter * desired preload force. Desired preload force is both what holds your scope in place (via friction) and what can crush your scope if it’s too high. (Nut factor is a combination of thread friction and bolt head friction, and is more or less a constant for a given pair of materials/coatings.)
The overwhelming majority of scope rings out there use really small screws, which need low torque values to not break, and several screws to ensure the scope is held with enough force to resist recoil. The ARC rings use a larger screw that takes more torque to tighten properly, but you only need the one to hold your scope in place. Vortex gives the torque spec for the 99.999% of the market.
This. One of the few people here who understands how this shit works. ^
I just follow the instructions, Ted is far smarter and more educated than me.
I know this is an old thread, but there were a couple mentions of using lubrication which I'm curious about.
It was my understanding that a fairly significant amount of the torque applied to a fastener went towards overcoming friction, so when you lubricate the fastener and use the same amount of torque, you get much more bolt loading. When the torque you're applying is to keep a fastener from backing out (and you're not on the verge of fastener failure) then you use the same amount of torque, wet or dry, as the lubrication affects loosening just like tightening. All you care about is how much torque it takes to get the fastener to move.
For rifle scope rings, the torque isn't (just) to keep the fastener secure, it's to provide the appropriate amount of clamping force on the scope tube to keep it from slipping under recoil while not deforming the tube. In this case, lubricating the ring screws and using the same amount of torque applies more clamping force then the manufacturer's specified (dry) torque setting. So use caution when lubricating scope fasteners.
Do I have this wrong? I'm no mechanical engineer.
It was my understanding that a fairly significant amount of the torque applied to a fastener went towards overcoming friction, so when you lubricate the fastener and use the same amount of torque, you get much more bolt loading. When the torque you're applying is to keep a fastener from backing out (and you're not on the verge of fastener failure) then you use the same amount of torque, wet or dry, as the lubrication affects loosening just like tightening. All you care about is how much torque it takes to get the fastener to move.
For rifle scope rings, the torque isn't (just) to keep the fastener secure, it's to provide the appropriate amount of clamping force on the scope tube to keep it from slipping under recoil while not deforming the tube. In this case, lubricating the ring screws and using the same amount of torque applies more clamping force then the manufacturer's specified (dry) torque setting. So use caution when lubricating scope fasteners.
Do I have this wrong? I'm no mechanical engineer.
That’s fairly accurate. It’s not too common that you’re not trying to get a clamp load with a fastener, though - basically, only shoulder bolt applications are concerned only with backing out. Everything else wants to clamp, so you’re carrying shear loads through a friction interface between parts instead of through the bolt shank.
The good news is that most of the time in firearms there’s a very wide range between “holding scope” and “crushing scope” and a smaller range between “lubricated optimal torque” and “dry optimal torque”, and “not backing out” is a lower value. As such, the generic torque value of 15-25 in-lb is suitable for wet or dry torque in most applications.
ARC specifies wet torque with either oil or anti seize per the instructions. Conveniently, they also give an approximate torque-angle spec for people who don’t have torque drivers of some kind (which everyone doing any firearms work should).
Torqued to the specs listed for the rings on several different scopes. No issues whatsoever and I'd love to switch all my scopes to ARC rings. Seems overkill on my 22's. 
