View Full Version : Picatinny Scout Mount for K31

January 9, 2010, 11:38 AM
I need a Picatinny scope mount to replace the rear sight on a K31. I have done an exhaustive search and can only come up with weaver style mounts, not true 1913 MIL SPEC Picatinny, and there IS a huge difference in slot spacing. Can anyone out there help? Thanks.

January 9, 2010, 12:27 PM
I suppose that would have some viability for a scope mount without permanently altering the rifle. I suggest you cruise on over to Surplus Rifle dot com also and navigate to the proper forum. Between here and there you are sure to find out if such a critter exists.

January 9, 2010, 01:19 PM
Thank you JHenry. I went to Surplus Rifle site and from the link for K31 found two suppliers, neither of which offer Picatinny spaced mounts but one of them, S & K has a weaver style base that I may buy and modify the spacing to Picatinny. I have bought S & K scout type mounts for my 91/30 Mosin and 24/7 Mauser and they are rock solid due to an additional support bracket that screws into the rear fixed sight base and is an anchor point attached by a screw to the rear of the scope mount. That mount won't budge. I would rather have a production Picatinny spaced mount but it may not be as solid a platform.
I know this sounds like unnecessary trouble but I use QRW rings (quick release rings) on my scopes that allow me to switch easily between rifles. I just keep a plastic covered spreadsheet with the elevation and windage corrections for each of my rifles, for that scope from the baseline rifle. I have a number of expensive scopes (NForce and Leupold) and after spending that kind of money would like to be able to enjoy my investment on several rifles. BTW the system really works and returns to zero within about one MOA or better.
Thanks again for your input.

January 9, 2010, 06:54 PM
You are most welcome. Please post some results when you have it figured out. Each of the two K31's I have been able to play with had very nice triggers and were superbly accurate. Pricey ammo for a surplus rifle though.

January 10, 2010, 11:10 AM
Thanks for your trigger comments. I'm hoping for the same and my rifle will arrive in a couple of days. I will post a range report when I get a good base and put some rounds down range. Yesterday I ordered three boxes of Privi Partizan loaded ammo (boxer primed, non-corrosive) from Midway for about $16.50 a box (20). I've reloaded PP and Wolf Gold brass with good results in other calibers and sure beats $120 per 100 cases of Lapua or Norma, although I'm sure they set the standard.
Do you reload for your K31's? I just bought RCBS FL, NK and seating dies and a Lee Factory Crimp die. I plan on loading Sierra 165 GameKings and will probably work up my load, starting with 43g of AA4064. Any reloading comments or differences you've experience with the "straight pull" bolt? Any bolt lug locking issues? I have been told it is possible for the gun to fire without the bolt completely rotated and lugs not fully engaged.


January 10, 2010, 02:15 PM
The two K31's belonged to a friend. All the ammo was Swiss surplus, so I am no use regarding reloading information for the round. The rifle cycles very smoothly, and is machined to an exceptionally high standard. I have no qualms in saying a rifle action like that could not be produced today for less than a thousand dollars. I also have 'heard' of the possibility of the rifle firing out of battery, but have not seen any evidence to make me believe it.

The Swiss ammo had a tiny ring of beeswax right at the cannelure. Don't know why.

January 10, 2010, 07:54 PM
I read yesterday that all the ammo the Swiss made for it used non-corrosive primers which accounts for why I've always heard that the bores of K31's are typically beautiful.

January 17, 2010, 08:59 AM
A picatinny mount won't work on the k31 except in the scout position and requires a LER scope, blocks the issue open sights and is less than desireable for hunting. If a standard scope mount rail is any wider than 3/8" it will interfere with brass ejection on the left, and skin your knuckles on the right when you cycle the bolt.
We've been building these mounts now for 13 years and have a load of failed prototypes on the shelf.
The following is from my son's own forum and might be of some help.

I don't mean the best mounts or accessories. You all know how I feel about that, but I mean what's the best setup. This is my blanket answer to a large number of emails that come each week to ask this question. This may not be what's best for you, but it is best for me and a lot of new guys who don't have budgets for exotic scopes or even the extra dollars for a steel mount. Being the son of an owner I can have anything I want for my k31s, and there's some pretty cool scopes here, but if you're the average guy with one k31 and the money for one mount and one reasonable scope, this is what all of us here at SP recommend and what I use too.

The rifle in the pictures is one of my personal rifles given to me by my Dad. Its one of the load data gathering rifles so you'll see it has a D/T mount on the left side, and that's because a scope on that side works best in the Accurite Shooting Device for hands-off firing, but I actually never use that mount. I use an aluminum right side clamp on mount. I can see no reason to pay the extra dollars for a steel mount at all, and all of us here feel the same way. Dad introduced it because of demand, and for no other reason.

The scopes we use for Swiss Rifles are compact variable, or our preferred compact fixed 4, 6 or 8 power very low profiles to get the scope as low down to the level of the bore as possible. My ring screws always face the outside of the receiver, never the inside. Brass ejection will tell you why.




Keep it simple, keep it low, tune/accurize your rifle as simply as possible without physically changing it and you'll shoot side by side with the expensive stuff.

Hope that helped you somewhat, Huck.


January 17, 2010, 09:23 AM

The mount in the picture is what I use on my K-31. Brownell's has them for $75 or so and with a 60's vintage Weaver K4 it looks right and works right too.

January 17, 2010, 09:33 AM
And for just a little less, Graf & Son's also is one of our distributors. http://www.grafs.com/product/272087

I'm a big believer and user of fixed 6 and 8 power scopes on these rifles.


January 18, 2010, 11:06 PM

Is this what you have in mind ?

I have this mount on one of my K31 rifles. Very nice.
This is a four point drill & tap mount that rides directly
over the bore.




January 20, 2010, 11:21 PM
Thanks to everyone for your helpful replies and pictures; some really nice looking scoped K31's. I have been mounting "scout" scopes on Mosins and several types of Mausers, and in each case was able to find one piece bases (mounts) that replaced the rear sight with Picatinny spaced slots, so that I can (and do) change LER scopes between rifles, keeping track of the correction in windage and elevation for each rifle for a particular scope. Contrary to what some may think, this does work well and can achieve one MOA results with handloads. I'm a P-dog shooter and don't settle for much less, but must admit one of my Mosins is only good for Minute of Hog.
What I have decided to go with is a very solid mount designed by Darrell Harrison. It does not have Picatinny spaced slots but the first and last slots are spaced the same as the first and eighth slots on a Picatinny. Somewhat of a compromise but that will work for me.
Again thanks for taking the time to help.