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A knowledgeable contact wrote that Blaser's and Mauser's engineers must have been on drugs when they designed systems that needed proprietary scope mounts. Maybe he's got a point. They would only be worth putting up with and worth their cost if they were very good at their job, of providing quick and convenient detachability, repeatability and consistent accuracy. Fortunately, every review I've found and every comment from contacts familiar with their performance states that they provide exactly that.
Blaser's R93 and R8 Saddle Mounts are interchangeable between the two models. Some Blaser owners are cranky that they're the only parts that are interchangeable. Blaser scope rings are made from aluminium. Mauser rings are made from steel. Of particular interest, the R93 rings fit and look right on the M03 Double Square Mount bases. The R8 rings will also fit but don't look quite right, having right angled sides instead of the curved sides that the R93 and M03 rings have.
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| A dodgy photo of an R93 Saddle Mount and rings, showing curved sides of ring stems. |
Blaser Saddle Mounts allow lower scope mounting than Mauser M03 Double Square Mounts. The Blaser mounts take advantage of being fitted on the barrel reinforce, such that the tapering barrel provides room for the scope's objective bell. With M03s, the Double Square Mount fits as a bridge over the receiver and positions the objective bell over the barrel reinforce. More on this later.
Some shooters place high value on having a 'good cheek weld', i.e. having their cheek flap compressed to provide a solid cushion between their cheek bone and the rifle butt. I don't. Not only does it cause wrinkles that would make a Hollywood starlet freak out, it messes with my vision, with how my spectacles sit and causes contact between the stock and ear muffs. Of course this could all be because the shape of my head is funny. With heavy recoiling rifles it can also make walnut crash into bone. The walnut always wins. I'm happy with a looser rest that is quicker to establish, where I have the side of my jaw making contact with the stock. Because I'm not a crocodile I can move my jaw up and down and side to side, which makes for convenient aligning of eye to scope. As such, a particularly low scope mounting system is not something I need. So, not a win for Blaser.
The Blaser mount bases are adjustable with a screwdriver for how tightly they clamp onto the barrel.
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| R8 Saddle Mount, showing a raiser block between base and ring. Note right angle base of rings. |
The Mauser M03 Double Square Mount is self adjusting by means of a cupped spring steel washer that acts on the shaft of the rotating cloverleaf. These washers, one at each end, are flattened when the cloverleaves are rotated to engage with the mount bases in the receiver. I took a few macro photos to show how it all works. Sorry about the fluff. The cupped spring steel washer is seen surrounding the shaft at bottom right of the second picture.
By all accounts the performance of the Blaser and Mauser scope mounts is equal. However, I'm informed that there can be a point of difference in repeatability if switching a barrel between multiple receivers. In this case, because the Blaser scope mount rides on the barrel there may be less shift in point of impact. That's understandable - but I'm hesitant to record this as a win for Blaser as I don't plan to switch barrels across multiple receivers. If I do, I'll map the respective scope and barrel to each receiver.
A gunsmith who is very familiar with both systems advised me that the M03 Double Square Mount locks to its receiver more strongly than the Blaser Saddle Mount clamps to its barrel. From looking at the two, I'd have to agree. However, as I'm constantly vigilant about isolating my scopes from bumps and don't plan to use the rifle and scope as an anchor for abseiling, I'm calling it a draw.
p.s. Re the last pic in the previous post, a closeup of an M03 Extreme, note that the scope mount rear lever's locking tab is not sitting in its slot properly. It looks like the lever needs a bit more of a push, to rotate the cloverleaf a touch more. With that, the locking tab will be able to settle into the slot.
p.s. Re the last pic in the previous post, a closeup of an M03 Extreme, note that the scope mount rear lever's locking tab is not sitting in its slot properly. It looks like the lever needs a bit more of a push, to rotate the cloverleaf a touch more. With that, the locking tab will be able to settle into the slot.
Hi I have two M03 rifles and 3 qr bridge mounts. 2 of the bridge mounts fit both rifles, albeit a little tighter on one. The 3rd is tight on one but will not fully engage on the one that is tight for the two mounts . Is there any way to adjust the bridge mount locking tension? Cheers Mark
ReplyDeleteHello Mark. Yes, I think you will be able to 'adjust' the locking tension of the mounts. If you see in the last photo in this post, at the bottom left there is a piece that has a washer. Adjusting the thickness of this washer (or the washer under it??) will increase or decrease the locking tension. I suggest you pull the mount apart as shown in this post, to figure out whether the washer needs to be thicker or thinner. If the tension is too tight, I think the washer needs to be a tiny bit thinner. Fact is, I haven't needed to make an adjustment to the tension of my mounts. However, I've just had another look at one and I'm quite sure that reducing the thickness of 'the' washer will reduce the locking tightness. The washer performs the function of pulling the three rotating locking tabs upwards. Therefore, a thicker washer will make the locking mechanism tighter.
DeleteAs a suggestion, see what happens if you reassemble the mount with the washer left out altogether. I'm thinking the tension will be very loose. Reassemble with a thinner test washer to see what happens. Measure the thickness and all the other dimensions of the original washer before you start to work on it to make it thinner (only after you've confirmed that you're on the right track.) But still, if it goes wrong, a washer should be easy to source and replace.
I might be imagining it, but I have this vague memory that the washer could be cupped and made from spring steel, so that it provides spring tension. Mark, when you pull your mount apart, can you advise on this please? Thanks.
Regards, Rick.
Mark, a second thought I'm having is that your tight mount could be affected by being twisted during its mounting onto a scope. A symptom if this is slight rocking of the mount on the receiver after being put in place but before the rotating tabs are turned. I noticed this when I first installed these mounts, leading to me writing a detailed post on how to install the mounts and scope onto a rifle, in a tension free manner. I'll add a link to that post. Here it is:
Deletehttp://mauserm03blog.blogspot.com.au/2017/05/mauser-m03-installing-riflescopes-to.html
Regards, Rick.
Thanks for the amasing blog.
ReplyDeleteI have two M03's, one with a wooden stock and one synthetic. I got the synthetic latter on....
Now the two scopes I got with my wooden stock fits perfectly with the synthectic. I tested to POI which did differ but not hugely.
However, the scope that came with the synthetic stock doesn't want to seat on the wooden one, the front part will seat independently but not the rear. It is as if it sits to high and doesn't want to "drop in" like my other mounts.
Found the Mauser instructions that explain the procedure:
When to use it: If the DSM locking lever will not lock or is difficult to lock, Mauser says the washers in the scope mount can be “adapted.”
Close the locking lever on the DSM before beginning.
Apply one drop of oil to the locking surface of the mount.
Front lug first:
Insert only the front locking lug into the front receiver base.
Keep the DSM oriented exactly as shown in Mauser's diagram.
Rotate the DSM approximately 60° toward the rear, in the direction of the stock, following the arrow in the diagram.
Remove the DSM completely.
Rear lug second:
Repeat the same process using only the rear locking lug in the rear receiver base.
Follow the second diagram exactly; because you're now working with the rear lug, the apparent direction/orientation differs from the front procedure.
Rotate through approximately 60° as illustrated.
Remove the DSM again.
Reinstall the DSM normally according to the standard M03 mounting instructions.
Lock the DSM normally and check its fit
( https://www.blaser-group.com/wp-content/uploads/Downloads_MAUSER/Bedienungsanleitungen/MAUSER_BD_Zielfernrohr_Montage_M03_web.pdf )
Now I am worried if I follow this procedure that I will lose some of the locking tension when reverting back to my synthetic stock.
Any tips in this regard? Or just better to visit a gun smith?
All the best from SA
Hi Branderplank.
DeleteThanks for posting your comment. And thanks for the link. I recall seeing a video from years ago where a guy in a gunshop does this 'adaption' process with a new Mauser M03 and scope mount. My feeling at the time was that it was a step I would take only if I couldn't find a clearer explanation as to why a scope mount would not fit to a receiver easily. As it turns out, I've never used the scope mount adaption process.
Some mounts that were very tight when first used have become slightly easier to remove and re-install, though they are still a tight fit. Perhaps the tight, rear mount you've described is like the new ones I bought used to be - tight to start with but loosen up with time and some use?
I'm sure you've already checked that all of the mounting surfaces for the scope mounts and the receiver's mount base recesses are clean and slightly oiled.
In one of my other posts I write about how the mounts might not fit easily and evenly onto a receiver if the top screws in the scope rings were tightened in a way that twists the mount on the scope. This problem shows up when both front and rear mounts are placed onto the receiver at the same time. If there is twist, the bases of the mounts can rock slightly on the receiver. However, it shouldn't be noticeable when putting just the rear mount into the receiver.
Hmmm, what to do in your case?
- Have you compared the tightness of the tight rear mount on both the rear mounting holes of your two receivers? Is there a difference?
- how about separating the cloverleaf/washer from the bridge with its cylinders and seeing if the cylinders fit more easily into the recesses? You will see a picture showing the disassembled mount in this post.
Good luck with these tests. I'll stand by for news. Regards, Rick.
Thanks Rick
ReplyDeleteSpoke to a gunsmith who knows his way around M03’s and he clearly understood my issue.
Incidentally I also ordered a new dsm and the same issue persisted. It would seat on both bases but it would not close.
Hopefully I can observe what the gunsmith will do when I take it in. But for now I am no closer to getting it to fit.
Thanks
Hi Brander.
DeleteThanks for the update. Well done on finding your M03 knowledgeable gunsmith. There's not too many of those around.
I'm encouraged by your news that the new Double Square Mount seats on both bases. This suggests that there isn't a problem with the dimensions of the seating cylinder on the DSM or the matching recess in the receiver. The fact that the locking mechanism won't close is suggesting that the problem really is being caused by something being too thick in that mechanism.
When I disassembled the DSM shown in the pictures in this post it looked to me that the washer is a cupped spring washer. If I understand correctly, this spring washer provides the locking tension for the rotating cloverleaf. So reducing the thickness of the washer by a fraction would be an option in your case. This could be a less aggressive approach than the 'bedding' procedure, which I'm simply not a fan of given the chance of causing wear on mating surfaces and increasing mount fitting tolerances. I'd rather find myself needing to put a shim in with the washer to make the installation tighter again, than end up with a mount that was looser than I wanted and in ways that can't easily be rectified. On the other hand, it's Mauser that shows us the bedding procedure, so perhaps my concerns are groundless.
Another thought about the bedding procedure with the new mount - your situation is that the mount fits in the receivers but the locking mechanism won't close. This means that there is excess thickness in either the washer or the upper face of the cloverleaf or the lower, inside face of the receiver's inverse cloverleaf. While I can see how the bedding procedure will force the cloverleaf and inverse cloverleaf surfaces to rub against each other and wear slightly, I can't see how this procedure can cause any wear or bedding affect to the washer. Hmmm, ... I'm still curious about what effect you can achieve from reducing the thickness of the washer.
As a test, what happens if you assemble the mount and leave the washer out? The locking cloverleaf should be really loose. It would be handy if you had a bunch of shims you could experiment with, or even better, a selection of cupped spring washers of varying thicknesses. Ha! I've used an old mechanic's set of feeler gauges to make small washers and shims of particular sizes.
Anyway, I'll be interested in your and/or the gunsmith's findings. :-)
Regards, Rick.