Finn m/39 Mosin-Nagant - new LER scope mount

[Dutchman]

This mount is made by modifying a NcStar picatinny rail for the Marlin lever rifles. I've used this rail for a lot of other mounts and it's proven itself to be very useful. This exact idea came to me one night in that place between awake and asleep and it proved so simple I just shook my head in disbelief that I hadn't thought of it before now.

This photo below shows the unaltered NcStar rail above and the modified rail below. The modification is comprised of 4 milling cuts and 2 holes drilled. The rail is affixed to the rifle via the ladder pin and one M4x.7 socket head screw. The existing setscrew on the Finn m/39 serves only to hold the rear sight base in place during soldering. It may unscrew easily, as mine did, or may have been soldered in place at the bottom. In the event your setscrew is soldered in place it would require you removed the barreled action from the stock and use a propane (only!) torch just on the screw itself until it unscrews. The solder is just lead-tin solder, not silver solder.

In the bottom rail, top left corner you'll notice an OOPS! I get to keep all the factory rejects for use on my own rifles :-?.

http://images108.fotki.com/v191/photos/2/28344/6806565/photo-vi.jpg

As with everything there are problems to work out. This photo below shows the first problem. The Weaver "low" rings were too low. The scope turret set right on the rear sight base protective "ears". The whole point of this exercise in long eye relief scope mounts is to make the mount lower than any other available LER scope mounts. In this case it's Darryl's and the S&K. My mount achieves this goal. But those protective ears defeat the primary goal. Drats! It may be that Weaver "medium" QD rings will fit perfect. The off-set ring is not required they were just the only other set of rings I had that were adequate height.

http://images12.fotki.com/v20/photos/2/28344/6806565/photo-vi.jpg

http://images14.fotki.com/v373/photos/2/28344/6806565/photo-vi.jpg

http://images61.fotki.com/v249/photos/2/28344/6806565/photo-vi.jpg

In my minuscule collection of scope rings were this set of off-set rings. Higher than the Weaver "low" they work for the time being. But you can clearly see there is room to lower the scope further.

http://images54.fotki.com/v514/photos/2/28344/6806565/photo-vi.jpg

It looks like there may be only about 1/4" between the scope turret and the sight base ears. It may not pay to blindly buy rings hoping to close that small gap. This may be as good as it gets.

http://images12.fotki.com/v213/photos/2/28344/6806565/photo-vi.jpg

The scope I used is the UAG shown below. Overall length is shorter than the NcStar but the distance from the eyepiece to the turret is the same.

http://images15.fotki.com/v792/photos/2/28344/6806565/photo-vi.jpg

This scope features a built-in spirit level. I figured what the heck, give it a try. Turns out the green fluid is too thin, like water, and is difficult to keep level. It should be, IMO, an oil fluid to slow down the bubble movement.

http://images46.fotki.com/v4/photos/2/28344/6806565/photo-vi.jpg

I have enough of the NcStar rails to make 6 more of these Finn m/39 mounts. The really good part of all this is I can do these for $35 delivered in the U.S. Baring any drastic price increases for the NcStar rail I can hold that price for the time being. Send me an email or PM through the forum. I'll have these 6 done this next week. I do not collect $$ before the item is ready to mail. If more than 6 respond I'll order some more rails. You no like? No problem. Send it back no questions asked and I'll refund every penny plus your return postage.

This below is the mount I first made 12 years ago. It was successful in proving the concept but failed on two levels...

Scope shown is Tasco 3x28 pistol scope. The eye relief of this scope is longer than the NcStar 2-7x32 that I now use exclusively. The mount sits higher than necessary over the ladder pin location. And the rearward scope ring needed to sit behind the rear sight in order to situate the NcStar for it's much closer 8.7-10.7" eye relief. Both of those handicaps were easily remedied but I didn't pursue any further m/39 design changes until recently. In my new design I saw no good reason to scratch-machine a mount when the NcStar rail fit the bill so beautifully without a lot of fuss.

http://images58.fotki.com/v612/photos/2/28344/6806565/photo1-vi.jpg

[skeet1]

Dutchman,
Very nice work please let us know how well your M39 shoots with this scope. I was very interested in seeing your rifle, the stock is very similar in color to my 1944 VKT.

[Dutchman]

Dutchman,
Very nice work please let us know how well your M39 shoots with this scope. I was very interested in seeing your rifle, the stock is very similar in color to my 1944 VKT.

The rifle in the first photos is a 1944 VKT with Sako stock. The stock has some nice flash to it. While I do handload for 7.62x54R and have multiple cast bullets for that caliber I have not yet worked on developing cast loads for the Finn m/39 due mainly to the lack of a scope mount. I've become very spoiled in that so many of my favored Mausers are now equipped with my LER scope mounts and by using the scope it eliminates a lot of shooter error in load development. The m/39 in the last photo from 12 yrs ago was a 1941 VKT. I gave that rifle to a young lad in Ohio along with that scope mount.

I do have some 7.62x54R loaded with Unique and 311299. I'll have to shoot that up to free up the brass. I also have 314299 and Lee GB 311407 .314". I've not loaded that in anything as yet. I am looking forward to working with the m/39 but I also have the German Commission Gewehr 1888 on the short list for this summer's shooting.

Dutch

[I'll Make Mine]

Nice mount idea, there. I've been thinking for a bit about drilling and tapping the scope base on my 91/30 to mount a rail for a low scout scope; I've even got a piece of Weaver rail that I got with a red dot that could be converted like yours, and I'd only need one screw with your setup using the sight leaf pin in front. That means I'm going to have to find an affordable LER scope (the NC Star looks like a good choice for my budget) and a cheek pad for the stock (I can make one of those easily enough), and I'll be able to hit stuff better at longer ranges (in theory, at least).

[madsenshooter]

I bought one of those UAG scopes that had a problem. The tube forward of the adjustment turret was smaller than the tube behind the turret. I couldn't get enough vertical adjustment to get on paper at 100yds. I see your mount has some elevation adjustment, that would have solved the problem, but I was using a Kraghaus mount, which doesn't have any sort of adjustment. They took the scope back and refunded my money, no problem.

[Dark Helmet]

My mount arrived already, now when will I get to mount it and add a scope to it????

[Finnmike]

Just dropping a note to let all know that it took me all of 10 minutes to remove the rear sight ladder, spring and screw from a Finn Sako 1944 and attach the mount and a 2x7 Bushnell LER scope tonight. Dutch makes great stuff, thanks, Dutch! Monday I'm taking her to the range for some shooting with Russian and Czech milsurp. Cast comes later. Report will follow.

[Uncle Grinch]

I got mine from Dutch a week ago and just found a scope that I bought off Amazon, so once they are together, I get to try it all out.

Thanks Dutch.

[Dutchman]

Thanks for the feedback.

There are 3 going out tomorrow, June 3rd. These were paid via money orders so if you're waiting it won't be long now.

There are 20 more rails inbound.


Dutch

[frnkeore]

Dutchman,
That's a great mount. Can you use that same rail on a 1888 Commision? Or have you not checked it out yet?

Frank

[Dutchman]

Dutchman,
That's a great mount. Can you use that same rail on a 1888 Commision? Or have you not checked it out yet?

Frank

Not checked it out yet. But I think no. There is different machine work required for the Gewehr 1888.

Dutch

[mike in co]

dutch,,,
any chance of replacing the front pin with two small allen cap screws ??

[Dutchman]

dutch,,,
any chance of replacing the front pin with two small allen cap screws ??

That idea did occur to me. The holes in the sight base will allow a M3 screw to enter. But the hole in the rail would have to be the tap drill size and not the ladder pin size. To do this I would have to use a more precise drilling operation using a drill bushing sized for the tap drill so the holes would be centered for the tap. I ran through the logistics of doing it that way and decided that using the ladder pin was the best method.

I've not completely discarded the idea of using screws but it would complicate the manufacture.

If you're having a problem drop me an email and explain what it is and we'll figure it out. If I need to replace your mount I'll do that.

Dutch

[Dutchman]

I use a loose m/39 rear sight base as a drilling fixture for the ladder pin holes. I have to drill the holes from each side so it's a 2 step operation. The ladder pin holes on this particular base were enlarged to #31 (.120") to act as a drill bushing and guide the drill.

Today I received 2 new unused m/39 rear sight bases from Mark Kubes in Florida to use in this project. Figured I better get them while they were available.

http://images60.fotki.com/v367/photos/2/28344/6806565/photo-vi.jpg

[Hang Fire]

I use a loose m/39 rear sight base as a drilling fixture for the ladder pin holes. I have to drill the holes from each side so it's a 2 step operation. The ladder pin holes on this particular base were enlarged to #31 (.120") to act as a drill bushing and guide the drill.

Today I received 2 new unused m/39 rear sight bases from Mark Kubes in Florida to use in this project. Figured I better get them while they were available.

http://images60.fotki.com/v367/photos/2/28344/6806565/photo-vi.jpg

Too bad there is not enough meat at pin ears, where could drill larger hole for inserting a substantial size hardened drill bushing there for tap drill.

But, I also think the present pin set up will work just fine, not much chance of play with only .0015” difference and being locked down with screw at rear.

[hylander]

I'm interested
I took the sight screw out of my M39 and it only has 3-4 threads.
Will this be enough to properly hold the mount.
It looks like some solder may have filled some threads at the bottom.

[Hang Fire]

Which threads take the load and stress?

http://www.gizmology.net/nutsbolts.htm

"....the first thread takes a third of the load, the first three threads take three-quarters of the load, and the first six threads take essentially the whole load."

1 34% 34%
2 23% 55%
3 16% 71%
4 11% 82%
5 9% 91%
6 7% 98%

[Dutchman]

This shows the underside of the sight base. The M4 screw does not extend further than the thickness of the part. I just measured that thickness and it is .117".

I'm seriously rethinking about using two M3 screws instead of the ladder pin. There was a problem with drilling that left a couple rails with one of the holes lower because the drilling fixture I was using enlarged the hole allowing the drill to slip. I'm replacing one that got past me and I screwed up 2 more. If you purchased one and find that there's a problem with the pin holes let me know and I'll replace it no problem. But I'm thinking I can drill out the .118" pin hole to .125" and make a drill bushing for .098" #40 drill which is the tap drill for the M3x.5 screw. I found that I have a box of M3x.5x10mm socket head screws already.

In the photo showing the side view through the ladder pin hole you can see that there isn't a complete flat surface for the drill to make a nice clean hole. It slopes. And it's real close to the drill point. It just couldn't be simple and present me a nice complete flat surface, Nooooo it's got make life difficult with what should be a very simple job :).

http://images50.fotki.com/v1523/photos/2/28344/6806565/photo1-vi.jpg

http://images60.fotki.com/v367/photos/2/28344/6806565/photo-vi.jpg

[Hang Fire]

Dutch, knowing you are more knowledgeable about machining than I.

But, would a much stiffer center drill suffice as a starter drill to prevent drift of the .120” drill?

Know it would be another machining step, but in the tapered areas of mount to be drilled, could a small flat be milled first?

[hylander]

Dutch, knowing you are more knowledgeable about machining than I.

But, would a much stiffer center drill suffice as a starter drill to prevent drift of the .120” drill?

Know it would be another machining step, but in the tapered areas of mount to be drilled, could a small flat be milled first?


Or a bottom cut end mill bit ?
Don't know if they even make one that small

[Uncle Grinch]

Dutch,

I tried to install the mount I got from you today and am having trouble drifting out the hinge pin for the ladder. I used a clamp to press the flat spring down and remove the pressure. I tried drifting from the right side (looking down barrel from rcvr) and then the left side. Nothing budged in either direction.

BTW... my sight has the very same number as yours (86432).

[Dutchman]

Dutch,

I tried to install the mount I got from you today and am having trouble drifting out the hinge pin for the ladder. I used a clamp to press the flat spring down and remove the pressure. I tried drifting from the right side (looking down barrel from rcvr) and then the left side. Nothing budged in either direction.

BTW... my sight has the very same number as yours (86432).


I use Mayhew starter punch, 1/16" size. Then the regular punch. It may take a good heathy smack if it's never been removed. But it is not a tapered pin and there's no reason it won't come out... eventually.

Those numbers 86432 are the range numbers in yards. Do you know how many guys thought that was the serial number of their rifle? (me too).

Dutch

[Hang Fire]

Dutch,

I tried to install the mount I got from you today and am having trouble drifting out the hinge pin for the ladder. I used a clamp to press the flat spring down and remove the pressure. I tried drifting from the right side (looking down barrel from rcvr) and then the left side. Nothing budged in either direction.

BTW... my sight has the very same number as yours (86432).


Mine was difficult to start movement, but after that was pretty easy.

[frnkeore]

"And yet another possible solution is to mill a dedicated drill fixture from scratch with a hardened drill bushing and revert to the original plan of using a .120" drill and the ladder pin as the method of attachment. This would involve a couple hours more milling time and a block of 1"x1" square steel plus some more math to locate the holes. This is a viable solution but we'll put it on the back burner for the time being."

Yes :)

If you stop by, you can use my height gage for the locations of the holes.

Frank

[hylander]

So where we at ?

[Dutchman]

So where we at ?

I received 20 more rails yesterday so this next week I'll be out in the shop. I'll post here in this thread when I have some ready to mail out. I don't collect $$ until the item is finished.

Dutch

[LIMPINGJ]

What ring and scope are combination are you that have Dutch's mount using? I have the mount and the work Dutch has done looks first rate now I just need to know what rings and scope to look for. Thanks all.

[Fishman]

I gave the mount to my dad and we mounted it last weekend using "rifleman" medium rings made by weaver. The low mounts did not work due to the sight ears. For a scope we used an older 2x Simmons pistol scope he had laying around. The eye relief was perfect with the scope mounted as far away from your eye as the base allowed. He hasn't shot it yet but everything looks good. Now I need to buy one for myself :)

[LIMPINGJ]

Thanks Fishman, with your and Dutchman having to use a medium ring heigth I will get a set ordered.

[Dutchman]

I deleted a couple unnecessary notes in this thread.

Update 7-2-13

I re-engineered the front attachment doing away with the ladder pin and instead using two M3x.5 socket head screws threaded into the rail itself.

http://images51.fotki.com/v747/photos/2/28344/6806565/photo1-vi.jpg
http://images51.fotki.com/v424/photos/2/28344/6806565/photo1-vi.jpg
http://images50.fotki.com/v1529/photos/2/28344/6806565/photo-vi.jpg

It makes no difference in actual use, either method of attachment. But there was a minor logistical problem in the way I drilled the rail for the ladder pin which resulted in mis-alignment in a couple rails. One got past me and is being replaced.

http://images59.fotki.com/v684/photos/2/28344/6806565/photo1-vi.jpg

I drilled out the rear sight base to .125" from .1185" (3mm). Then I made a simple drill bushing that I hold in place manually while drilling with the #40 (.098") drill.

http://images49.fotki.com/v560/photos/2/28344/6806565/photo-vi.jpg
http://images20.fotki.com/v113/photos/2/28344/6806565/photo-vi.jpg

Then I made a simple guide bushing for the M3 tap that I hold manually while tapping. In practice it worked out real good.

http://images58.fotki.com/v154/photos/2/28344/6806565/photo1-vi.jpg

There are 9 more that'll be done in the next few days. Out of those 9 I think 6 or 7 are spoke for but I have an additional 10 rails ready to start. $35 delivered in the U.S. Let me know via PM or email if you're interested. If you've already let me know then I already have your contact information and I'll notify you when the mounts are ready to mail. I don't collect funds until things are completely finished. Paypal or money order, either way is fine.

Dutch

[bluewater]

Dutch, I would like to buy one picatinny rail from you. Please check you PM or email. Thanks!

[oscarflytyer]

Will these work on the Russian MN, or just a Finn? I have both. Thanx

[bluewater]

Will these work on the Russian MN, or just a Finn? I have both. Thanx

This is just for the Finn. For Russian MN, I bought the following from Amazon:

83803

This (http://www.youtube.com/watch?v=49iG-i_Mi84) Youtube shows how to install. I don't need to cut the upper barrel cover because I use the NcStar rings. Here is my Mosin with the scope:

83809

I have put thru 100 MilSup boolits with the scope. At 50 Yards, it is sub-MOA and the scope holds up well. Hope it helps.

[Dutchman]

Not doing any more of these. I've moved on to a new project, sorry.

Dutch

[bluewater]

Dutch, too bad that you are not doing it anymore. It is such a good design. If you decide to do it again, please let us know as I am sure that the demand is there.