Scope clamp screw torque on ARC M-brace rings with a Sightron SVIII 5-40x56.

[ETXshortrange]

Hello,
Is anyone using this ring and scope combination. If so, what torque are you using on the single scope clamp screw?

ARC installation instructions are to use 55 inch pounds on the single scope clamp screw. Sightron mounting instructions are to limit scope clamp screw torque to 15 – 18 inch pounds. The Sightron supplied rings have four clamp screws. According to information on various internet forums, the total clamping force of the Sightron supplied rings is between 60 - 72 inch pounds. I contacted Sightron customer service and they stated "We recommend 15 to18 inch pounds. At 55 inch pounds the focus will not work." I plan to use this scope and ring combo on a 300 win mag and do not know if 18 inch pounds on the single scope clamp screw will be sufficient to prevent slippage.

 

[LoneTraveler]

On a magnum, If the scope is heavy, You may want to switch to a set of rings with 2 screws on each side of ring and more contact area.

 

[wldcat]

It needs to be 55 inch pounds, Sightron either isn't familiar with arc rings or they are only willing to spout off generic info based off traditional ring design. The larger diameter screw that's used has a corse thread pitch which applies less clamping force per given torque value. I've never tried to run them at only 18 inch pounds but I do run them at 55 with no problems. Quote from arc about torque

"Yes, this is higher than typical. American Rifle's rings use a larger diameter scope clamp screw than that used by most other
manufacturers of rings. To clamp the scope tube with a force similar to rings having multiple small screws, a higher torque
must be applied to the single larger scope clamp screw on American Rifle's Rings.

 

[FEENIX]

Hello,
Is anyone using this ring and scope combination. If so, what torque are you using on the single scope clamp screw?

ARC installation instructions are to use 55 inch pounds on the single scope clamp screw. Sightron mounting instructions are to limit scope clamp screw torque to 15 – 18 inch pounds. The Sightron supplied rings have four clamp screws. According to information on various internet forums, the total clamping force of the Sightron supplied rings is between 60 - 72 inch pounds. I contacted Sightron customer service and they stated "We recommend 15 to18 inch pounds. At 55 inch pounds the focus will not work." I plan to use this scope and ring combo on a 300 win mag and do not know if 18 inch pounds on the single scope clamp screw will be sufficient to prevent slippage.

@wldcat is correct, follow ARC's recommendation of 55 in-lbs, not Sightron's.

Here is the link to ARC's installation instructions: https://americanrifle.odoo.com/web/content/59269

 

[solocam808]

Good info, just ordered some ARC rings myself.

 

[William W.]

I always use Badger Max-50's with 3-screws on each side.

 

[blackburbot]

It needs to be 55 inch pounds, Sightron either isn't familiar with arc rings or they are only willing to spout off generic info based off traditional ring design. The larger diameter screw that's used has a corse thread pitch which applies less clamping force per given torque value. I've never tried to run them at only 18 inch pounds but I do run them at 55 with no problems. Quote from arc about torque

"Yes, this is higher than typical. American Rifle's rings use a larger diameter scope clamp screw than that used by most other
manufacturers of rings. To clamp the scope tube with a force similar to rings having multiple small screws, a higher torque
must be applied to the single larger scope clamp screw on American Rifle's Rings.

I have a couple sightrons and when they say under 20inch pounds they mean under 20. The scopes have been back and forth to the repair depot many times because the parallax keeps on breaking. Every time the say the rings are clamped too tight and thats been on spuhr mounts at 25in-lb. On 6dasher fclass rifles. So its definately not the recoil taking them out. Maybe i have a couple bad scopes for strength but optics aresuler nice so i keep on using them. There hasnt been tube damage to the scopes but internal adjustments come loose. Try fol.owing Sightrons suggestions of 20 and go from there. You should know within 10 shots if they are not holding

 

[waveslayer]

Sell the scope, ARC rings are some of the best rings out there. You shouldn't be having an issue like that.

 

[Schw15]

Arc makes great rings that never fail. Follow torque specs you won't have any issues I know at first it sounds crazy and a lot of torque compared to other rings but gtg

 

[Will.284]

Mabye the rings are to close to the ends of the scope , I had a problem with a U.S Optics that way so I moved the in a notch and used proper torque and waalaa no problem

 

[Schw15]

Just throw those sightron rings in trash. We had same setup 300 win mag and they slipped like crazy!!! I told my dad buy the arc rings well he did after they haha

I never had rings slip before til then.

 

[JAYgs8163]

ARC is 55 inch pounds for the scope tube ring screw. They are of unique design and are one of the best for sure!

Are you sure this info below you mentioned is not referring to the base clamp screws on the Sightron rings?

"According to information on various internet forums, the total clamping force of the Sightron supplied rings is between 60 - 72 inch pounds."

 

[jrg]

@wldcat is correct, follow ARC's recommendation of 55 in-lbs, not Sightron's.

Here is the link to ARC's installation instructions: https://americanrifle.odoo.com/web/content/59269

We Run ARC RINGS on our 6 BRs & have for about 5 years now on Nightforce scopes. we have always torqued at 55 inch Lbs. with no problem at all. Of Course, there is very little recoil with the 6BR, but I would recommend these rings for any combination. Also, there are no ring marks on your scope!

 

[hottuit]

On a magnum, If the scope is heavy, You may want to switch to a set of rings with 2 screws on each side of ring and more contact area.

All my Magnums are four screw per ring DNZ American made rings. Game Reaper 2 or Tactical Hottuit!