Last updated 6.6.2013

L.E.R.
Long Eye Relief
Scope Mounts
For Vintage Military Rifles

A Study in Concept, Design and Manufacture

June 6, 2013 - Building a better mousetrap - the Gewehr 1898 German infantry rifle


Update June 6, 2013: I am now making a LER mount for the Finn m/39 Mosin-Nagant rifle. This is the only mount I'm currently making.
Please do not email and ask about other mounts at this time.
Email for availability and price.





A high percentage of milsurp collectors and shooters are now older and afflicted with the universal fuzzy eye syndrom.
We like shooting but can't see the sights so well anymore.

The second group are those who enjoy hunting with their collectable military rifle but find the sights aren't calibrated or otherwise suited to hunting. Many rifles, as with the 1896 Swedish Mauser, are calibrated to zero at 300 meters rendering them fairly useless unless changed or otherwise modified. The object of this discussion centers around mounting optical sights to collectable rifles without modifying or permenently altering them and damaging their future collectability and monetary value.



A couple random shots of the rifle I'll now use as my standard "shooter". It's a 1908 Carl Gustaf with a like-new bore and overall a very nice rifle. It's featured on this page.




This rifle has proven itself very capable with jacketed bullets from 85 gr HP to the 160 gr Hornady round nose.


The 1900 Oberndorf FrankenSwede will be set aside for a while. It hasn't shot as accurate as I'd like and falls way short of competing with the 1908 I'm now shooting. It has a pretty good bore but it may need some bedding help.


This 1919 Gustaf has been my primary range rifle for many years. But the barrel needs to be replaced. It has a great deal of wear showing. It'll put 5 cast bullets into 1" at 50 yds but it won't do any better than that. I prefer 5 shots into 1 hole at 50 yards. I took the scope off and installed a Soderin diopter and front target sight. I want to see how it shoots with those sights before I decide what to do with the rifle. I have one new spare m/96 barrel.



[Begin Update Dec. 27, 2009]

This last week I installed a mount for my son-in-law's father's nice elm stocked 1917 m/96. Dropped right in with only the slightest resistance. Perfect fit. Almost like it was made for it! They ordered a scope from a vendor off ebay that I'd done business with before, Ultimate Arms on ebay.(low prices & fast shipping).

They ordered the 2-7x32 handgun scope. Erroneously, I thought these were the same as NcStar. They're not. Dimensionally there's a couple differences. The overall length could be explained by the varying focal length but the distance from the turret to the front of the bell was 1/2" shorter on the UAG scope. They aren't indentical. So the scope arrived today and they got it installed.




I shouldered the rifle and was surprised at how well the scope was presented to the shooter's view. Eye relief was perfect. I had thought these scopes had too short eye relief to work well with the Swede m/96 LER mount but this was real nice. What made it nicer were the very low rings. They were a set of rings picked up from the local gunshop down the street for about $15. Kwik-Site model KS-WEV for scopes up to 32mm objective lens diameter. Lower than "low" Weaver rings.




Nice 4 screw caps make getting crosshairs straight easy compared with the headache of Weaver rings.


The "quick release" version of these rings are KS-302. They're pretty much like the Weaver with a coin slot nut.







Kwik-Site




[Update Oct. 27, 09]

Out with the old...

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This is m/96 LER V.4




This mount now uses the top hat anchor instead of a setscrew. And this V.4 is only .004" higher than V.3 which means its very low.
It is a tad shorter by 1/4" to 5/16" than V.3.

It still has the limitations regarding ring position and eye relief adjustment. So this mount will require a long eye relief scope longer than the NcStar series of LER scopes. That's the limitation for this particular mount.


The circle shows the surface that you would touch up with a smooth file to fit between the ladder ears.

I have 3 loose m/96 rear sight bases and 2 m/96 rifles in the shop. They are not all the same distance between the ladder ears. But this dimensional discrepency is due mostly to injury or damage to the rear sight, or burrs on the metal. Most likely, though, its due to some damage in use or when the rifle was rebarreled and the rear sight base was removed and re-soldered to the new barrel. The back end of the sight base is often smacked to loosen it. This particular rifle bears that damage, though it is 109 years old.


The arrows indicate the dimension between the ladder ears. This is really the only critial dimension on this mount. You should check your rifle to make sure there's no burrs on the inside of the ladder ears that would interfere with the LER mount setting down into the rear sight base.

Depending on the rifle the LER insert may drop in with gentle thumb pressure or it may require a stronger push but should not be forced or hit with a hammer (!). If it won't drop in then the insert needs to be touched up with a single cut smooth 6" or 8" file, a little at a time, until it just pushes into place. I would prefer an insert that you have to fine tune to your rifle.

Nov.6, '09 Note - This top hat anchor is now being made from 1045 carbon steel. I chose this material in case bending of the .038" flange becomes an issue. The 1045 can be heat treated fairly easy with a small torch and a water quench followed by 1 hour in a 500 degree oven and water quench to temper. It won't bend again.


The arrows show the center-line distance between the ladder pin hole and the top hat screw. This may be a source for the insert not dropping right into place because this fit is too tight between the arrows. Easy fix.


Take your file and touch up the front curved surface of the anchor flange. You can try turning the anchor around so the flat side of the flange is up front but with the curved edge of the flange forward it fits in the front part of the spring slot providing more support and strength.

The thickness of this flange may need fine fitting with the file on the bottom to thin it somewhat. I'd prefer a fit that needs fine tuning than one that's too loose. None of these adjustments require anything more than a single cut smooth file 6" or 8" in length.
And use a file handle!


What about elevation correction?

It may not be nessesary but if it is you may cut circular shims 5/16" diameter with a #8 clearance hole and place them (one, two, three .010" .020" etc) on top of the top hat anchor and put it back together.

If the ladder pin won't enter the hole because the mount is now tilted you can file a small radius on the front edge where the circle shows. The front position of the mount is controled by the ladder pin. Using a file on the underside won't change anything other than providing some clearance for elevation movement.

Personally I don't care for screw adjustments for elevation on LER mounts. What do screws do? They come loose and change.
The shim method is foolproof and won't change.

Oxpho Blue (cold blue) from Brownell's if you need to touch up after fine tuning. Degreasing is the key no matter what the instructions say. I use denatured alcohol.

[/end Update Oct. 26, 09]

This mount is now 10 years old. It was made in 1999.




[begin update July 11, 2010]

Czech Persian 98/29 8x57mm long rifle


The Czech Persian is now outfitted with a new NcStar 2-7x32 scope. The mount is as far as I can take it, as low as I can make it.


The forward ring needs to be moved up a wee bit.


I have 3 or 4 of these mounts available for sale as of July 11, 2010.


This rifle definitely found some cast bullets and loads it likes.




The Czech Persian 98/29 rear sight is identical in design to the K98k Mauser in that it has a removable tangent bed rear sight.


Instead of designing the LER mount to replace the tangent bed I left the tangent bed in place and made the LER insert as if it were like the
1908 Brazilian & 1909 Argentine Mausers.




I also experimented by getting the rail as low as possible even to the point of milling the NcStar Weaver base to clear the "ears" of the sight base.







[begin Jan.30, '10 update]
1891 Argentine Mauser rifle




This shows the height difference between the Argentine m/1891 on the left and m/1895 Chilean on the right. They are otherwise identical.
The m/1895 mount will also fit the m/1893 Spanish rifle as they have the same rear sight. With such a variety of rifle models there's bound to be some that require some fine fitting of the insert into the sight base.


This is the 1895 Chilean mount. Height is pretty much governed by the handguard.

It goes without saying but I'm saying it anyway: You don't like this mount for any reason and I don't care if you threw it out in the street and watched a truck run over it,
I'll refund 100% plus your return postage. Nobody gets stuck buying one of these mounts from me. This goes for any of these mounts. I don't want you to keep a mount if you aren't happy with it. Life's too short.


The top one is for the m/1895 and bottom for the m/1891. Only difference is the roll pin location as the back end of the m/1891 mount is much thinner than the m/1895 so I had to move the roll pin. The 3 sockethead screws are 8-36. The far right screw is the anchor screw. It'll be a 8-40 Torq head that goes into the sliding anchor.

Oops.. looks like the bottom mount has 2 Torq head screws. I'll have to see why I used those there.
Some of the screws have to be shortened by hand in a little jig used on the bench grinder.


Detail of the rear end attachment.


Front end clearances.


View of the underside.


The mount for the 1891 is as low as I could get it. The steel insert is 1/4" thick while the 1895 Chilean is 3/8" thick. There's still the same amount of milling on both as the bottom side is identical and they both use the same sliding anchor. That presented a problem with the 1891 mount, at least for one screw. I had to use a M4 metric Weaver screw as there was so little meat to thread with the tap. But the other two holes are 8-40 and there are two 1/8" roll pins added for repeatible alignment and strength. I'm not real happy with the Oxpho Blue cold blue. I've gotten some really good results and some medicore results. I'm looking for something better but it has to be a cold dip process.

I bought this kit from Caswell's. It does a better job and does batches all together instead of one at a time. Its still more labor intensive than I'd like but the only alternative is to send all the mounts out to a commercial shop and that means $$$.




The new mounts for the 91/93/95 mounts no longer straddles the outside of the rear sight base as this one does. Instead they all align down the interior. The reason being the 93/95 have handguards that prohibit the outside straddling of the insert. Plus there was a machining aspect to that particular design that made it more difficult to mill.


This is how all the 91/93/95 mounts will be. While they're drop-in there's always a chance you may have to do a tiny bit of fitting with a smooth file. But I've taken pains (sore fingers!) to hand-fit all of these to a like-new 1891 Argentine rifle and a loose 1895 Chilean barrel. Each insert has to drop in both those "gauges".


This is the critical part for the 91/93/95 LER scope mount. It has to be a "push" fit in the ladder spring slot. It can't be sloppy. It took me 45 minutes of file-try-file-try-file-try. This sliding anchor provides the integrity of the whole mount. I'll supply this part close but you'll have to fit it.
I'd guess no more than a couple/few thousandths of an inch.

And this is how you do it.....


Use your trusty $20 electronic calipers to measure your ladder spring where it slides into the base.





[/end update Jan. 12, 2010]



Some 98 Mausers with non-removeable tangent base rear sights:

1908 Brazilian Mauser
1909 Argentine Mauser
Czech 98/22
...and many others


This is a 1908 Brazilian Mauser caliber 7x57mm. The tangent curve is built into the rear sight base.
This type of rear sight base presents a different design criteria than the K98k or other rifles.

The Brazilian 1908 mount turned out very well. Extremely solid.



This scope is the NcStar 4x32 so it has a shorter eye relief. This is why the scope sits further back towards the shooter's eye.
This position is perfect for me in the off-hand or bench position.


These photos show the sequence to bring this mount to completion. This is the steel insert being fitted into the confines of rear sight base. In most cases this is the biggest challenge.


For expedience I used a NcStar rail for the Marlin rifle as it has a flat base and is drilled for mounting holes. The slot configuration is in the mil-std-1913 instead of the Weaver slot spacing. At 4 3/4" long its ideal for this type of application.


This shows the second biggest challenge: height. There's less than 1/8" between the bottom of the rail and the handguard. On rifles with handguard of this type there's no way around having to have the rail in this position if we want to have adequate ring and eye relief adjustment. Its still lower than other mounts of this type.


This is the top hat anchor before the fine fitting. For this first one I hand-fitted this anchor. The width is .500" and the thickness .038".






The hole for the pin in the sight base where the sight leaf pivots on isn't really a pin hole. Its one of the Mauser ideas to make sure the rear sight doesn't get lost if the leaf spring breaks and the leaf wants to drop out. There's a tiny diameter pin that protrudes into this hole to keep the sight leaf from being lost. I lathe turned a pin for a close fit and since this hole is pretty good size it lends great strength to the entire mount.


This shows the pin in place during the fitting.



Mauser Model 1909 Argentina
7.65x53mm

There is nothing the .308 Winchester can do that the 7.65x53 can't do better.... in the 1909 rifle.

You do not push handloads in the 1891 Argentine Mauser. The 1909 is the rifle to push the envelope if you must.


I bought this rifle from a collector friend because it was the perfect rifle for me. I didn't want one that was too cherry, that I'd have a coniption fit if I set it down and it fell over. This rifle has wear and tear on the outside but it's a 100% matching rifle and the bore is immaculate.


The scope mount here will be re-worked so it's lower like the 98/29 Czech Persian. This Tasco Custom Shop 7x scope with it's 30mm tube is huge and a bit obnoxious. And the eye relief is very touchy. Its just not very comfortable for this type of use. It'll be another 2-7x32 scope.


The 1909 didn't do quite as well as the 1891 but I'll wait until I can put a different scope on it and shoot it some more. It also seemed to prefer the .314" cast bullet.

The 1909 Argentine Mauser caliber 7.65x53mm is nearly identical to the 1908 Brazilian.

Not dimensionally identical.

Notice I used M4x.7 buttonhead screws through the elevator holes in the base. There are thin nylon washers that'll go underneath the screw head to protect the blue finish.

This particular rifle was aquired from Century Arms in Vermont as a U-Fix-Em... basically it was a junker that cost all of $18 with free shipping.
Its 100% complete down to the cleaning rod. But it's wore out and has terribly excessive headspace. I've shot it only with moderate cast bullet loads.
The bore isn't wore out, just the rest of the rifle. It's thought that these chromed rifles were used in the Argentine navy, not as parade rifles as is generally thought.
But my recollection may be garbled...






These 1908 and 1909 rear sight bases are very common among 98 Mauser contract rifles.



Moving into an area of entirely different rear sight base design are the following:
  • German Commission Gewehr 1888
  • 1893 German-made for South Africa Boers & Spanish models 7x57mm
  • Japanese Arisaka Type 99 (and possibly Type 38)


German Commission Gewehr 1888


With the ladder upright....


1893 DWM South African-Chilean 7x57mm.

This particular Mauser rear sight is shared with the 1891 Argentine and 1895 Chilean Mauser. When in the down position the elevator slides to the top of the ladder and locks into a dovetail located integral with the ladder spring. This leaves the two edges of the ladder with a perfectly functional clamping surface about 1.8" long. It'll take a prototype to determine if this method of attachment is adequate. The German Commission 1888 and the Japanese Type 99 don't have a similar ladder locking feature.


...and with the ladder upright.



There are some commerically available LER mounts in the marketplace.
Darrell's Scout Mounts, S&K and B-Square are the primary players.


Darrell has designed and supplies LER mounts for several vintage military rifles.
Shown there is a Swiss K31 with a very popular mount.

All photos of Darrell's mounts are used with permission:m39scout at bellsouth.net

The K31 mount.


Another very popular model by Darrell is this one for the m/39 Finn Mosin-Nagant
7.62x54R rifle.


The Russian/Soviet 1891/30 Mosin-Nagant rifle.

A closer view of the 1891/30 Russian Mosin-Nagant mount.

Darrell also markets a mount for the m/44 Mosin-Nagant carbine.

In corresponding with Darrell he offered these insights into the design and construction
of his LER mounts:

1 - My mounts are machined from solid billet, high strength, aircraft aluminum alloy. They are then black matte anodized.
The alloy that I use has a yield strength (40Kpsi) that is higher than that of standard low carbon steel (26Kpsi-32Kpsi),
and it only weighs about 1/3 of what it would weigh if made from steel. This gives it a tremendously good strength to weight
ratio, and allows for adding some extra "beef" to the mount, while keeping it light. The anodizing also adds some scratch
resistance and surface toughness to the mount. This is the THE BEST material for the job and any other material would only
be heavier and/or much more expensive without improving real world performance.

2 - I supply brass setscrew with my mounts, because 99% of my customers are collectors that do not want to permanently dimple,
scratch, damage or alter their C&R firearms in any way. However, if one is not concerned with scratching or dimpling the finish
and needs a little "feel good" insurance, then one can certainly substitute steel screws for the brass, by going to Home Depot,
Lowes, etc. to purchase replacement steel screws; however, that really is unnecessary.

2a - The screws work together as a system. The front and rear elevation screws account for virtually all of the holding power
to lock and bind the mount in place. The 4 side clamping screws act as stabilizers and force multipliers to improve the
holding power of the elevation screws.

2b - I supply a replacement pivot pin (roll-pin), but that is just for completion or "spare". You can use your original
pivot pin with no problem.

3 - The Weaver rail is machined into the mount. There are no windage adjustments in the mount, but, I have never needed
such a feature, and my scopes have always had more than enough windage adjustment to take care of my needs.

4 - I send complete instructions and a drawing for installation and initial alignment. When the mounts are installed
according to my instructions, they are rock solid, and no problems with them coming loose.

My own obervation of Darrell's mounts:

Since Darrell first began marketing this LER design I've watched and listened to his customer's feedback. Its one
thing to hawk your own goods but the real meat 'n' taters comes from the users of the product. In this regard I've
not ever heard or read of one complaint about Darrell's LER mounts. That fact got my attention. At present I don't
own any of Darrell's mounts so my entire opinion is based upon customer feedback and my own observation of the mounts
themselves. I'm keenly interested in LER mounts so those that succeed I tend to pay attention to. I do plan on
purchasing two of Darrell's mounts. One for the K31 Swiss and the other for the Russian 91/30 as I don't intend
on designing mounts for those myself.



S&K


This is a Swedish m/96 with an S&K LER mount.


It attaches with the same "top hat" anchor as above.


I've recommended the S&K when I've received queries about a LER mount for the m/96 rifle.
I like the S&K for two reasons and dislike it for two reasons.

Like:

  • Good solid attachment
  • Good overall design
Dislike:
  • Sits too high, unnessesarily high
  • Uses proprietary rings - should be Weaver
  • Not enough ring position or eye relief adjustment

Ok, so I can't count. Still, even with out of balance likes versus dislikes I think the S&K mounts
are the best that we have available to us commercially for the m/96 Swedish Mauser and I'll continue
recommending them for certain models of rifles. Some of the S&K mounts I just don't like for design reasons.
[edited Oct.27,09]



And then there's the B-Square-------


The B-Square on the m/96 Swedish Mauser 6.5x55.


The screw to the far right is a strain screw.


The B-Square clamps around the ladder and then uses a strain screw to push upwards and hold the mount
in place. Its adequate... barely. There have been B-Square used on hunting rifles with great success.
Of this I won't dispute. But the B-Square is an inexpensive solution to a problem that needs a little more
attention to sound design principles, not to mention stronger attachment methods. But it'll put meat in the pot.


Meat in the pot with B-Square.


My scope mount making machine is this Index Model 40H vertical milling machine.
Built in 1942 for Douglas Aircraft in Long Beach, California for US Navy aviation.

It has a #9 Brown & Sharp spindle, 8x28" table, weighs 1,200 lbs and is entirely
adequate and accurate for a home shop. I've owned it 25 years.






My new(er) vertical milling machine.
Enco 1525 made in Taiwan in 1993.
Three phase, 10 speeds, lots of power and
lots more capacity than my 1942 Index
Model 40H.

With digital read-out (DRO)
and power table feed.


















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D.L.van den Brink
~Dutchman~
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