Questions Regarding Scope Rail Dimensions and Loose Scope Mounts

Discussion in 'General Sako Discussions' started by EVR, Oct 5, 2019.

  1. EVR

    EVR Member

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    Has anyone experienced significant looseness in initial fitting of Optilock or older SAKO "Optilock"-style mounts?


    I have two rifles and one allows a lot of slop before tightening the clamp.

    I'm concerned about the .375 shooting loose since the only recoil stop is the pin since neither mount sits tight in the dovetail, except for the lateral clamping provided by the screw and claw.

    Your experiences would be appreciated!
     
    Last edited: Oct 5, 2019

  2. paulsonconstruction

    paulsonconstruction Sako-addicted

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    The "pin" is not a recoil stop, but rather an index so one can remove & replace the scope at the same location to help maintain zero. Recoil forces actually cause the scope to want to move forward on the dovetails. As the dovetails are tapered, this causes the mounts to self-tighten. The pin is actually a hinderance to the self-tightening design, which is why I remove it on any Sako ringmounts I use or just use Leupold ringmounts, which do not have the pin. The absence of the pin allows the rear ring to be placed anywhere on the dovetail if needed for eye relief. The scope mount bases for the turn-in Redfield style rings don't even have any screws for "tightening", but are just driven on the dovetails with a hammer & wood dowel & if you ever have to drive them off you will see how tight recoil can make them. It's simple physics. An object at rest(the scope) wants to stay at rest. When subjected to forces(recoil) causing the rifle to move backwards the scope is pulled backwards, but this movement is resisted by the ringmounts, thus causing them to transfer that force forward into the tapered dovetails. It's a wonderful design that a lot of people don't understand, which is why we see so many cobbled up scope mount systems on Sakos. The simplicity baffles them! Your mounts will be tighter after shooting than they are now & they will work better without the pin. Another way to think about it is if you place a box(scope) on a wheeled cart(rifle) & you suddenly jerk the cart the box falls off the opposite direction you pulled. Which is why the forces on the scope are forward(opposite) during the rearward movement(recoil) of the rifle.
     
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  3. EVR

    EVR Member

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    Thanks for that explanation.

    Sorry for the long post, but I think between what you have posted and this, anyone who doesn't understand the potential issues will now...

    I knew I should have posted pix in the first place...

    Basically, I understand what you are saying and did similarly with the front base on my 6.5 a few years ago when I set it up with Optilocks. I saw the issue you describe, but never thought about removing the rear pin.

    My current problem involves where the bases will STOP when slid on the receiver. I expected the bases used on my .375 to do the same when I replaced the old EAW scope mount with Optilocks on my .375, but ran into the following problem...

    In the following pix you'll see where one front base stops {on my 6.5} which is about in the middle of the receiver ring. That is fine. It has good "grab" and a positive stop in binding into the rail.

    HOWEVER.....

    ....on the .375, the front rail was machined about .010" smaller than on the 6.5. Thus, as you can see on the .375, the base will NOT fully seat into the receiver rail as you suggest and as I have done in the past UNTIL the front portion of the base is hanging off the receiver. It is unsightly at best. I SUPPOSE it would provide adequate purchase, yes?

    The rear is loose when slid on, and then the rear pin hits the wall in the groove on the receiver and the clamp snugs it all up from there. In this case, I fear removal of the pin for fear it would allow that base to slide forward, hang over the loading/ejection port and perhaps foul reloading.

    Now get this.....

    Curiously, I have another set of mounts which are SAKO mounts {which are basically the same system as the Optilocks except they use Allen instead of Torx screws, the instructions say the front base should be even with the rear of the receiver ring above the ejection port which of course means there is NO solid engagement of the mating surfaces of base and receiver and the clamp is what is holding it from moving forward. That seems no bueno to me...

    In the NEW Optilocks, instructions say one is to slide the base on the receiver ring till it stops and then tap the base with a plastic hammer to seat it. This makes more sense and is as you and I have done in the past. Seems to me they learned something along the way..... Like you, I did not "buy" the idea that the front base should just sit there without solid dovetail abutment and on my 6.5 with an older set of Optilocks that did NOT have the "plastic hammer" instructions I tapped the front base into solid engagement anyway. It just seemed right and you indicate you also do this.

    Now...my SAKO pre-Optilock "Optilock"-style mounts do approximately the same as the Optilocks except the front base does not hang over quite as far.

    It all boils down to this; I do not trust the pin and clamps to provide BOTH forward and lateral stability. I want engagement of the base in the receiver dovetail just as you have described. It looks like in order to achieve this I will have to allow the front base to hang over the barrel a little and the rear....well, I just don't know what to do with that... Because if I grind off the pin...will the clamp slide too far forward? No idea.

    And finally,

    Will Talley's take care of this problem?
     

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  4. paulsonconstruction

    paulsonconstruction Sako-addicted

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    I am not an Optilock fan & have not mounted them on anything because they all mount the scope way too high. Even their lows are too high. Plus they are two pieces instead of one & are heavy & bulky. Your front mount should not hang over the barrel like that(are you sure it's not on backwards? If not, something has been mismachined) & your scope is mounted way too high for a proper cheek weld. If you pull the trigger on a 375 and don't have a proper cheek weld it's going to smack your cheek bone & cause considerable discomfort. I would ditch those worthless Optilocks & get a set of the old original one piece Sako ringmounts or Leupold ringmonuts made for the Sako dovetails. Get a ring height that gives you a lower scope position so your eye lines up when your cheek weld is solid. I wouldn't go higher than a medium for the ringmounts I mentioned, then find a scope that will provide the barrel & bolt clearance needed. Most 375 shooters use a 1-4X, 1.5-5X or similar type scope with no forward bell so they can mount their scope as low as possible. If you can't hit anything you hunt with a 375 using a 4 or 5X, it's too far away. Another option would be the new style Sako one piece ringmounts. Haven't used any, but if the height is right they may work for you. Either way get away from the base/ring type system you now have. Good Luck!!
     
    Last edited: Oct 5, 2019
  5. EVR

    EVR Member

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    Thanks.

    No, the mount is on correctly. It's a angled dovetail. Trying it the other way prevents entrance onto the receiver rail.

    The problem with the mounts are as you suggest; the receiver is as stated above, machined to a slightly smaller dimension than the 6.5 rifle.

    Regarding your other comments, everyone has different ideas about what's best for sure. Over many years of hunting I've become quite well aware and familiar with various stock configurations and have come to like higher scope mounts and a headsup hold, particularly for moving game. I've used this same old .375 in question with EAW's which are as high for 35 years, using it so much the bluing was gone and it looked like stainless. I had it reblued a few years ago. I've killed game in Africa and all over the USA with it. I'm pretty familiar with the gun and cheek weld after several thousand shots. None of that is the problem. I also do not agree on the issue of scope magnification as in thick timber and in various other settings I've had numerous opportunity to use higher magnification for the purpose of threading shots thru otherwise unseen brush, etc. Put another way, there's no downside strictly-speaking, to added magnification options, especially if the rifle is used for off-season varminting which we do a lot of. As an aside, many years ago in Africa, with a 4x Leupold mounted on this rifle I shot a small tree clean in half and lost a nice impala due to the inability to see the tree as it ran right up the front leg of an impala and was invisible to all of us, blending in to the animal until it rose above the backline, giving the impression it was actually located behind the buck. All of us were dumbfounded as the little tree literally fell down as the critter took off sporting a hole in its butt then we all realized what had happened. The beauty of a variable is that one isn't limited by any single power within its range.

    I sent the Optilocks back to Eurooptic. I like the other set of them I have on my 6.5x55. I think I'll wind up selling the older SAKO "Optilock"-style mounts I have and also my old EAW mount which is still in very nice shape. The former would be fine on a caliber with less recoil and I wouldn't even worry about it, but on the .375 I want a bit more insurance. The EAW has been a very good mount but with the longer eyepiece of the new Leupold, it locates the scope just a bit too far back for me and my head position.

    I think I'll call Talley and see what they have to say about this whole affair and their bases/rings. Seems they get rave reviews pretty much everywhere and if I can get QD's that would be even better as I really want access to the irons. I've got the same Leupold 3.5-10 scope on my Sauer 9.3x62 and have to find a solution for the old Finn...

    Thanks for your input on the rails and base dovetails. Your assessment has solidified my thinking on it all and makes way more sense than the actual setup and instructions according to SAKO!
     
    Last edited: Oct 5, 2019
  6. Sean Hodges

    Sean Hodges Well-Known Member

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    Very strange anomaly for sure. The front dovetail difference seems to be the culprit. You have the correct Optilock base for a long action Sako. That is, ring rear of the screw, so the ring is far enough back to not cause a space issue regarding maintube length. My photo is the opposite - ring in front of the screw for a short action. Problematic for sure because any single base or ringmount MAY not work as designed or intended. I hope you find a workable solution.

    Edit: the rear of your base should stop near the ejection/loading port if the clamp is equal to the base body groove.
     

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    Last edited: Oct 5, 2019
  7. EVR

    EVR Member

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    Thanks.

    Yes, it's odd for sure.

    The rail hasn't been monkeyed with, but it does vary in dimensions a bit from the other rifle I have which was built during the same time period. I forget the years exactly. I've a hunch the Talley system might work or it might hang over, too. I'll call them on Monday or Tuesday. What's curious is that the EAW's fit fine.

    At least I know now the mounts are not the issue.

    When fitting the rear base w/ Optilocks, do you guys feel a lot of play between the base and receiver bridge BEFORE tightening the clamp? Seems to me this might be excessive, tho the other comment made a lot of sense...removing the pin and then letting the base slide forward to full contact of male and female rails would remove that lateral play. The rear one might not actually hang over, hard to say. The front does, but tapped in, would then be solid.

    Basically in a round about way, what I'm saying is that if push comes to shove, I could try removing the pin and then shoving both forward and running the clamps tight and just going with that. The front and maybe {?} the rear would be a bit unsightly to some degree, but I don't see why it wouldn't work. I THINK there would be enough purchase on the front and rear bases {even if the front hangs over...SEE PIX below} to secure the thing, both bases being wedged tightly in and then clamped. The front clamp of course is right at the front extreme of the receiver rail, but as long as there is some "bite" I don't think it would matter much. Only reason for the clamps is to keep the thing from sliding backwards, right? Which really, is unnecessary if the bases are wedged in tightly?

    Below are pix of the old-style SAKO precursor to the Optilock system. I still have these old ones and might use them, maybe, using the above modification {pin removal}. I installed them loosely here to show how much overhang there is on these on the front base {less than on the Optilocks}.

    Now...I'll toss in another curve-ball. I just found out from Beretta that a few Optilock bases have escaped QC and they are over-sized. So who knows, maybe the set I had were just out of spec a little as well and between that and the slight undersized rail, made for a very sloppy fit?{??}.
     

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    Last edited: Oct 5, 2019
  8. Sean Hodges

    Sean Hodges Well-Known Member

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    Once properly in place, play or movement should be very minimal. Typically I make sure the clamp is equal to the groove, then I push with my thumb until the front base stops. Typically again, the rear is even, or close to even with the ejection/loading port. The clamp once tightened obviously removes All play.

    Personally, I would not use the front base as shown in your picture. It goes way beyond the intended location and defies the correct installation standard. I’m never in favor of using products beyond their intended purpose. It usually spells trouble.

    Also, given the issue with the front base, I would not recommend removing the pin in the rear base. I mean you could, but again, we’re starting to monkey with things we probably shouldn’t. What if it all slid forward slightly during recoil? A chance I wouldn’t take even as careful as I am, regarding tightened screws.

    In my humble opinion, if the EAW mounts fit properly on your seemingly unique dovetail, then I’d continue use them, unless I’ve missed something about them in your posts. They’re a very high quality system built to very high quality standards. Best of luck.
     
  9. stonecreek

    stonecreek SCC Secretary Forum Owner SCC Board Member

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    It seems like in recent years Sako engineers have forgotten what the basic concept of their tapered dovetail is all about. The design of the Optilock rings (which are both heavy and expensive, as well as much too high to suit most of us) is overall a poor one, especially the two-piece ones. Who would design a mount with a base when there is already a base machined into the receiver?

    The original Sako ringmounts are among the best for Sako rifles -- but they get scarcer and more expensive every year. Since the patent on them is long-since expired someone could probably make a mint building new ones.

    Like paulson, I favor Leupold ringmounts if originals are not available. The Leupolds are simple, light in weight, very adaptable, and amply strong (I have had them mounted on a Sako .375 H&H for over 20 years without encountering a problem.) The Redfield/Burris system also works fairly well and due to the wide variety of ring sizes and heights (and extension rings) it is a fairly versatile system.

    I do not care for the Talley's since (1) they use an additional base, and (2) vertically split rings are very inconvenient when getting the scope crosshairs rotated to plumb and require some complicated mounting techniques if the ring serves as both the scope clamp and the base clamp. Talley's are also much more expensive that other, better-functioning mounts.
     
  10. EVR

    EVR Member

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    Basically, we're on the same page.

    Now I do NOT think the mounts will or even can move at all if wedged into the receiver rails just as paulsonconstruction said. I'm not really worried about that. I could see them shifting if they were not 100% wedged in and only the clamp was preventing forward movement.

    But as noted, the way the front base is set up in the pic is not ideal. I think it would work, and work solidly, but it's ugly and it shouldn't fit that way.

    One additional comment, to reiterate in case somebody else winds up reading this thread some day. The rear base when slid on obviously stops when the pin contacts the shoulder in the receiver. However, at that point, there is still a lot of lateral and rotational movement that is only taken up by the screw when the clamp is tightened. All of that movement could/would be eliminated by removing the pin and pushing the base forward till full contact occurs.

    In addition, I noticed that the rear clamp appears to have, or nearly have, bottomed out on the base. I almost missed that and I think it is significant. Yes, it appears pretty tight, but under recoil will it allow vibration or shifting of the rear base/ring assembly? It might. I think it will. Shoved forward, the gap on the screw between the clamp and the base will widen and allow plenty of tightening grip just as occurs on the front. Unless I'm missing something significant, this appears to be a far more secure arrangement than the "factory" setup. The theory appears to be proven in the change of instructions found in new sets of Optilocks pertaining to front base contact with the receiver where it now says to solidly bed the female base into the mail rail.

    As far as factory intentions are concerned, I've run in to quite a few engineering flaws in all sorts of gun products over the years so I'm not beyond going out on my own if an improvement can be found to a factory product. I THINK ugly as it might be, the above-discussed mods would be improvements, especially since they more accurately reflect the current instructions which must I suppose be based on experience and feedback given to the company.

    The EAW mounts I've used for all these years require the scope to sit too far back. They are great mounts but they don't work well with my scope and...face.
     
  11. Sean Hodges

    Sean Hodges Well-Known Member

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    Completely agree with your and Paulson’s posts. The potential issue I see is Leupold ringmounts MAY not tighten properly on the front dovetail based on the photos provided. If the dovetail is narrower by description, then the geometry MAY be skewed slightly to provide 100% positive lockup at a reasonable location. In other words, if the front ringmount is in a typical/reasonable location the clamp may tighten before making full contact with the dovetail. I guess one would have to try one to see.
     
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  12. EVR

    EVR Member

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    That's a good point RE: Leupolds.

    This has been a really helpful thread guys. Thanks.

    I'll run all this by Talley and see what they have to say. It seems every pic I can find of a Talley base on a SAKO has it stopping somewhere in the middle of the front receiver ring. That might be a good indication that on my rifle in spite of the slightly narrower rail, the base might stop somewhere close to...but not overhanging...the front receiver ring.
     
  13. Tomball

    Tomball Well-Known Member

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    CDEACEC4-FD4B-4C34-9051-1C0B5642CDA6.jpeg 3E965204-181E-403B-862A-30CF8FE243A6.jpeg
    Couple photos of Talley on L61R 270 heavy barrel. Only set I own since Talley made a deal at a gun show once. They work fine and took did not take long to mount. I use optilocks and have not had any issues, original Sako split mounts, Leupold and a few others.
     
  14. EVR

    EVR Member

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    OK, perfect.

    It looks like yours slid on and stopped appropriately with still some room to go if used on a gun like mine with a slightly narrower rail. I'm guessing with my front rail bases dimensioned as yours are would slide quite a bit farther on, but hopefully not too far...

    I hope so, as I would not mind a set of Talley QD's if they fit and hold.
     
  15. paulsonconstruction

    paulsonconstruction Sako-addicted

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    Talleys??? Why put an adapter that creates a dovetail on to an action that already has dovetails? Kinda redundant isn't it? The original Sako & Leupold ringmounts are capable of being "QD". All you have to do is put them back on the dovetails in the same location & your zero will change very little or at least no more than rings that are called "QD". Seems to me you all are making things way more complicated than necessary, but that's just me. I always favor the K.I.S.S. system
     
  16. EVR

    EVR Member

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    Unfortunately my rifle is making things complicated. Check out the thread again and you'll see that the issue is proper location of the rings and bases, and not having part of the base hanging off the front end of the receiver {and possibly ditto on the rear}.

    1} The SAKO & Optilock mounts do not fit correctly.
    2} No system that requires a combined base/ring to be driven into the rail will function properly as a QD mount.

    I'm curious as to if the Talley bases might allow better location of the base. We haven't discussed the Leupolds really but I'll give them a look, too, if need be.

    Putting an additional/separate piece between the receiver and the rings might seem at first blush to be "redundant" but if you understand the problem caused by the rifle, it would not be IF that additional piece serves to correct the location of the rings. I'm not at all sure if it will at this point, but will make some calls and find out more.

    Where an easily-detached scope is desired, I'm pretty convinced that the tapered rail is in general an inferior mounting system compared to some others. For example, I have a 16" barreled CZ 550 9.3x62 I use for bear. It is set up with Warne rings and works perfectly. Everything locks up good and stout and zero is repeatable with the removal and replacement of the scope. On and off, it holds zero. And I do use the irons when following hounds. Incidentally, the scope is a Leupold 3-9 variable with German #4 reticle. The Leupold version of that reticle cross-hair is really too thick for good precision at long range as it subtends too much of fine targets, but I don't use the rifle out of the timber anyway, and the 9x comes in very handy and is useful for carefully placing shots that avoid intervening brush.
     
    Last edited: Oct 6, 2019

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