"Precision" Scope Rings / Mount

Blackrifle1

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I buy the American Rifle Company (ARC) rings for almost all my rifles. I have them on 6 rifles and never, ever had a problem. They are affordable, (mid range cost) but they seem perfectly machined. They are one of the very few scope rings, mount, etc,.. I've ever noticed that when torqued properly, the "gap" between the 2 rings is always perfect and the same every single time time, when comparing from one to the other.

My question is : I've noticed alot of "precision" rings/mounts with odd gaps from one side to the other when torqued down, how are they "precision machined" if the gaps aren't exact everywhere? Shouldn't the rings/mount close perfectly with hardly any gap like the ARC's? Isn't that a part of what precision machined means?

I'm not knocking other brands, just trying to understand. I probably opened Pandora's box here, but Let the schooling begin!!!!
 

ICU22250

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    I dont know as the only precision rings I buy are ARC M10's.
     
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    308pirate

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    I buy the American Rifle Company (ARC) rings for almost all my rifles. I have them on 6 rifles and never, ever had a problem. They are affordable, (mid range cost) but they seem perfectly machined. They are one of the very few scope rings, mount, etc,.. I've ever noticed that when torqued properly, the "gap" between the 2 rings is always perfect and the same every single time time, when comparing from one to the other.

    My question is : I've noticed alot of "precision" rings/mounts with odd gaps from one side to the other when torqued down, how are they "precision machined" if the gaps aren't exact everywhere? Shouldn't the rings/mount close perfectly with hardly any gap like the ARC's? Isn't that a part of what precision machined means?

    I'm not knocking other brands, just trying to understand. I probably opened Pandora's box here, but Let the schooling begin!!!!

    Those gaps are installation, not manufacturing, error

    So many of you think the rings matter so much more than they actually do.

    LOLOL
     

    Jayhawkhuntclub

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    Those gaps are installation, not manufacturing, error

    So many of you think the rings matter so much more than they actually do.

    LOLOL
    Agreed. I've had many $50-100 rings and mounts that did all that was needed. If they are the right height and cant and come from a reputable manufacturer (Burris, Vortex...etc) I wouldn't worry.
     

    308pirate

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    Shouldn't the rings/mount close perfectly with hardly any gap like the ARC's? Isn't that a part of what precision machined means?
    No, that's not even close to what precision machined means

    I'm also betting that you think that every scope out there (including the $3K+ ones) are have zero variation in tube diameter and cylindricity........
     

    Blackrifle1

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    No, that's not even close to what precision machined means

    I'm also betting that you think that every scope out there (including the $3K+ ones) are have zero variation in tube diameter and cylindricity........
    ok, I asked a simple question that needed an answer, not a smartass answer like yours. If you simply can't answer my question without being a dick, then dont answer. This is why alot of people hate asking questions, because some dick like you has to be a know it all and answer like a dick. This is simply a place where people can learn, so try to be part of the solution, not the problem.
     

    Blackrifle1

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    Those gaps are installation, not manufacturing, error

    So many of you think the rings matter so much more than they actually do.

    LOLOL
    NO, that's NOT what I'm talking about, I said when "torqued properly" and you make them as even as can be on all sides, they still can have large gaps, unlike the every time perfect gap on the ARC 110 rings. So, tolerances (gap between the rings when "torqued properly" ) has nothing to do with precision?
     
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    308pirate

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    So, tolerances (gap between the rings when "torqued properly" ) has nothing to do with precision?
    Tolerances have nothing to do with gaps.

    I can torque all ring cap bolts to the correct value and still have an uneven gap.

    Tell me, what does having an even gap on both sides achieve? What do your ARC rings do better?

    And no, your question isn't a simple one. You just think that it is because you're making a bunch of assumptions.
     
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    Ludasmith

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    There's nothing mechanical keeping the two planes parallel to each other on most rings. You have an axis of rotation around the tube.

    To an extreme, you can tighten one side in three threads and tighten the other side 20 threads and it'll obviously be off.

    There might be something inherent with the ARC design that makes what you do naturally just so happen to work out, I've got not a clue.

    The "precision" is generally bore size, bore height consistency, and concentricity between the rings.
     

    308pirate

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    It would be nice if laymen would actually read through (even briefly) through some of the source materials available to anyone on the internet so they would know the real meaning of the word "tolerances", and then learn about basic and nominal dimensions, and classes of fits.

    Then they can do the same to learn the difference between precision and accuracy.

    That way they would stop sounding so ignorant, while thinking they're so smart.

    It's not that damned hard............
     
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    308pirate

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    NO, that's NOT what I'm talking about, I said when "torqued properly" and you make them as even as can be on all sides, they still can have large gaps, unlike the every time perfect gap on the ARC 110 rings. So, tolerances (gap between the rings when "torqued properly" ) has nothing to do with precision?

    If there is never a gap where the two halves of ARC rings meet, how do you know that the rings are tight around the scope? How do you know that the rings didn't bottom out against each other before they clamped around the scope?

    Do you think that every set ARC rings have zero dimensional variation and that scope main tubes likewise have zero variation in outside diameter?
     

    iceng

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    The gap left in rings is a result of the manufacturing process (on good rings anyway). The ring is made as a solid one piece unit, hole bored / cut out, and then cut the top off. The gap you see is the thickness of the blade.

    Because ARC have a different system of manuf, the 3 parts, which are seperate and not cut apart, they can close the gap up.

    The true "tolerance" is the hole diameter, be it 34, 30 or 1", and the accuracy of one ring to the next. A one piece ring are (usually) bored in one pass, rather than one ring at a time.
    This eliminates having to lap the rings.

    Hope I explained it well.
     

    308pirate

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    The true "tolerance" is the hole diameter, be it 34, 30 or 1", and the accuracy of one ring to the next.

    In a super overly simplified way, yes.

    The problem comes when laymen confuse fit tolerance with individual detail part tolerance and completely ignore the nominal dimensions of the two mating surfaces.

    An assembly can have (by design) a peg ground to 1.000 ± .0001 and a hole drill, bored, and reamed to 1.020 ± .0005 because the designer needs a loose fit for reliability (or whatever reason) and all the internet experts will bitch about the "loose tolerances". Well the fucking parts were machined to very tight tolerances..............weren't they?

    And more to the point, tolerances are only known to those who have the engineering drawings for detail parts and assemblies. Measuring a bunch of parts does not tell you what the tolerance of any individual part is, it just tells you the capability of the process that created whatever feature you measured.

    Two completely different things.
     

    Im2bent

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    So if he replaced tolerance with clearance would that make you happier?
    As to the ops question the manufacturers dont see a need to make the gaps as small as possible. Why? With more gap ( clearance) you have a little more wiggle room for manufacturing tolerance stacking. Say you only have a theoretical .001 gap between the ring halves. Depending upon the manufacturing tolerances it can be off abit say. 0005 to small and say scope x is .0005 too big...oh oh. Of course this is all layman speak so take it with a grain of salt.
     

    KnowNothing256

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    Wait a minute. ARC M10 rings have a single degree of freedom, the scope clamping screw at the top. Which means, when you define the torque, as long as the scope OD is correct and the ring interior machining is too, then that torque will define the gap.

    Am I right in thinking the OP is comparing this system to most other rings, that have two (at least) degrees of freedom, the gaps on either side? If so, OP, the irregular gaps are user imperfection, not machining issues. You don’t accuse a see-saw of being broken because it isn’t level when you put more weight on one side than the other.
     

    Blackrifle1

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    It would be nice if laymen would actually read through (even briefly) through some of the source materials available to anyone on the internet so they would know the real meaning of the word "tolerances", and then learn about basic and nominal dimensions, and classes of fits.

    Then they can do the same to learn the difference between precision and accuracy.

    That way they would stop sounding so ignorant, while thinking they're so smart.

    It's not that damned hard............
    This is the problem, when you want to look up information you get many different ideas, thoughts, recommendations from many different people, some nice and some with an attitude. You act like you know it all, even if you did, is it that hard to just reply to my question? Explain your side? I stated I wasn't knocking other ring/mount companies, just asked a question. Where in my post did I act so smart? I was asking a question to something I didn't know.

    Your right, its not that damn hard............to not be a DICK
     
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    Blackrifle1

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    Wait a minute. ARC M10 rings have a single degree of freedom, the scope clamping screw at the top. Which means, when you define the torque, as long as the scope OD is correct and the ring interior machining is too, then that torque will define the gap.

    Am I right in thinking the OP is comparing this system to most other rings, that have two (at least) degrees of freedom, the gaps on either side? If so, OP, the irregular gaps are user imperfection, not machining issues. You don’t accuse a see-saw of being broken because it isn’t level when you put more weight on one side than the other.

    Thank you for at least trying to understand instead of giving me backlash. I think you are on the right track of what I'm asking.

    When I tighten my ARC rings to the torque spec (recommended 50-55 inch lbs) the gap is very small and precise. They look like they fit "like a glove" around the scope. Other rings/mounts (not all) I've noticed even when perfectly torqued and spaced, there's a much larger gap between the ring halves. Sometimes like 3x larger gap than on my ARC's. I was simply asking about why such a large gap on some rings even though they are tightened and mounted correctly?
     

    KnowNothing256

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    Thank you for at least trying to understand instead of giving me backlash. I think you are on the right track of what I'm asking.

    When I tighten my ARC rings to the torque spec (recommended 50-55 inch lbs) the gap is very small and precise. They look like they fit "like a glove" around the scope. Other rings/mounts (not all) I've noticed even when perfectly torqued and spaced, there's a much larger gap between the ring halves. Sometimes like 3x larger gap than on my ARC's. I was simply asking about why such a large gap on some rings even though they are tightened and mounted correctly?
    Oh, ok, I follow. So, obviously I don’t know for sure, but I’d guess it’s to leave plenty of room to allow for imperfect spacing when tightening without bottoming out the gap on one side. If you totally close the gap on one side, the torque will be fairly meaningless, since you’re just compressing the ring material at that point instead of the scope tube.

    I wouldn’t consider this a design weakness, assuming I’m right, I’d actually posit that the manufacturers are allowing room for inevitable poor installation by the end users.

    ETA: Sorry, meant to mention the M10s too. These can have a smaller gap since the end user is only changing one dimension, and you can’t close the gap without drastically exceeding the torque spec and crumpling the scope tube (wouldn’t be surprised if it was designed to strip the threads out first or have the screw break, actually). Normal rings don’t have that mechanical limit, you can easily totally close the gap on one side if installing improperly, and it gets easier the less total gap is available.
     
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    Blackrifle1

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    If there is never a gap where the two halves of ARC rings meet, how do you know that the rings are tight around the scope? How do you know that the rings didn't bottom out against each other before they clamped around the scope?

    Do you think that every set ARC rings have zero dimensional variation and that scope main tubes likewise have zero variation in outside diameter?
    I NEVER said "is never a gap where the two halves of ARC rings meet"- I said in my original post - the "gap" between the 2 rings is always perfect and the same every single time time. They don't bottom out because the 2 clamps (in the case of the ARC rings) they aren't touching.

    I have NO idea what "zero dimensional variation and that scope main tubes likewise have zero variation in outside diameter is" , so if you could instead of berating people like myself that would like to know more and LEARN because we love the sport and guns, it would be HELPFUL to just answer my question. I'm sure whatever the question, it may be "stupid" to more the more experienced people, but you started somewhere, I guarantee it.
     

    Blackrifle1

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    Oh, ok, I follow. So, obviously I don’t know for sure, but I’d guess it’s to leave plenty of room to allow for imperfect spacing when tightening without bottoming out the gap on one side. If you totally close the gap on one side, the torque will be fairly meaningless, since you’re just compressing the ring material at that point instead of the scope tube.

    I wouldn’t consider this a design weakness, assuming I’m right, I’d actually posit that the manufacturers are allowing room for inevitable poor installation by the end users.

    ETA: Sorry, meant to mention the M10s too. These can have a smaller gap since the end user is only changing one dimension, and you can’t close the gap without drastically exceeding the torque spec and crumpling the scope tube (wouldn’t be surprised if it was designed to strip the threads out first or have the screw break, actually). Normal rings don’t have that mechanical limit, you can easily totally close the gap on one side if installing improperly, and it gets easier the less total gap is available.
    ok, THANK YOU for the explanation which makes alot of sense.
     

    iceng

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    Stuff said goes here.
    I agree with what you said, however the OP wanted a simple explanation, which I tried to do.

    Tolerance is "acceptable deviation from the required final size". +/- 0.02mm on a hole of 34.2mm for a scope ring would be stupid, however a +0.00/-0.04mm would technically be better (not optimal this is an example remember).

    If you then went 34.00 +/-0.02mm, or perhaps 34.00 +0.04/-0.00mm, etc. One could potentially be undersize, which is bad, but still in tolerance.

    Funnily enough, I believe too much emphasis is put on scope ring bore dia tolerance / measurement, and not enough in other areas.
     

    Blackrifle1

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    The gap left in rings is a result of the manufacturing process (on good rings anyway). The ring is made as a solid one piece unit, hole bored / cut out, and then cut the top off. The gap you see is the thickness of the blade.

    Because ARC have a different system of manuf, the 3 parts, which are seperate and not cut apart, they can close the gap up.

    The true "tolerance" is the hole diameter, be it 34, 30 or 1", and the accuracy of one ring to the next. A one piece ring are (usually) bored in one pass, rather than one ring at a time.
    This eliminates having to lap the rings.

    Hope I explained it well.
    Thank you for replying
     

    308pirate

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    Funnily enough, I believe too much emphasis is put on scope ring bore dia tolerance / measurement, and not enough in other areas.

    The bigger problem is that nobody who is obsessing over that even knows what the acceptable range of dimensions is supposed to be.
     
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    iceng

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    "our scope rings are made within a trillionth of a micron". Marketing magicians as I call them.

    "Look over here at this shiney thing while I do things you can't actually see".

    Every industry has it. I still get a good laugh when people spends $250 on a 710 cap for their rocker covers. Zero performance increase... "But it's billet alloy, it's reducing mass in the car, and heat dissipation properties of alloy is fantastic."
     
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    Steel head

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    I’m a pea brain, just like consistent and easy function and no issues and not over complicate things.
    3 ring sets I typically use because they’ve always treated me and my friends well at various cost levels are M-10’s(my favorites), seekins/vortex pro and weaver 6 bolts.
    The nightforce rings as well.
    Don’t be a gorilla or idiot and they always work well.
     

    lestersurv

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    Lots of neglected understanding when it comes to defining "precision"...
    One Sat night, about 15yrs ago, I measured all my rem 700 picatinny rails. Nightforce, Badger, Near Mfg, and a Warne. The Badger had a cant in its slots. Off about .005"...

    Probably no big deal, if you knew it was there; this off-center slotting on the Badger. Aside from reading an article about scope mounting by the gunsmith who was involved with the Houston Warehouse, I've never seen any discussion about truing scope base on a mount job. Many guys advocate blue or red loctite, but do they true the base to the bore? Never heard of it being done. The scope mounting article is in the Precision Shooting Benchrest Primer. A pretty good read.

    All in all, it's pretty difficult to overcome a machining error on something like a Picatinny rail. Until the flat top ARs and custom actions w/integral rails came out, there was always potential for great error in any mounting system.

    Some years later, I was swapping some scopes out. One was on a LaRue QD riser I used on a couple AR-10s. Swapping the AR-10 mounted scope to a Win 70 and then checking the install with a Bushnell boresighter-collimator, the scope from the AR/LaRue riser was 20moa off windage wise. I checked the other 2 LaRue riser mounted scopes and they were both off also, one by 30moa... While those scopes were "sighted-in", they for sure weren't anywhere near concentric to the bore.

    Once a scope was mounted to the Steel Weaver mounts on the Win 70 and zeroed by the collimator, I transferred the scope back to the flat top AR. It was still right-on, windage wise, after the transfer.

    Similar story with Leupold QR scope mounts. I had several Win 70 long actions with these 2pc bases, the ones with the lever on the base that locks onto the QR ring stem. You would think these would swap to same action and mount hole distances, but they didn't. Off significantly. Leupy made good on their product, but I was sure bummed the mounts could have such a variance. Apparently the QR function was only good on the same base set. Still, a pretty solid mount system for the hunter using more than one scope...

    If you want to talk about Jeweler Quality machine work, Richard Near makes the finest scope mounts and rings I've ever seen. I was a Big Fan of Badger Ord back in my day, but then changed to TPS for rings. Very much a fan of Warne's Maxima line now that they have the horizontal ring design.

    For those interested, the Houston Warehouse gunsmith was TJ Jackson, and the Precision Shooting article was titled "To Insure Centered Scope Mount" from 1986. Very detailed writing about the method Jackson followed to assure his customers had all their windage & elevation to work with. He would make no turret turns until he had the base mounted as precisely as possible. TJ wrote that he was using Weaver bases...

    Getting the right setup is most of the battle. Can't really rely on buying "the best" and fastening it all together.

    Lots more sloppy rifle mounts that I've bought over the years from quality makers. Always a good idea to have the ability to test your install and be able to diagnose problems that may arise.
     

    rustyinbend

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    ok, I asked a simple question that needed an answer, not a smartass answer like yours. If you simply can't answer my question without being a dick, then dont answer. This is why alot of people hate asking questions, because some dick like you has to be a know it all and answer like a dick. This is simply a place where people can learn, so try to be part of the solution, not the problem.
    Amen Brutha ... what is it about being online, that turns normally polite people, into keyboard-penises? I just don't get it. That said, I've learned three valuable lessons here: (1) Being abused is part of asking for advice, (2) If you ignore the abuse and focus on the advice you can get some great feedback, and (3) Responding to "Bear Pit" political threads is like running in the Special Olympics - even if you win, you're still retarded.