The Swiss K31...Finally.
By Joseph D'Alessandro Editor
In the beginning...
OK, so I didn't know the Swiss produced a rifle. I
know the Swiss monitor cow flatulence out of concern for methane byproduct, I know
I've seen some reference to chocolate at one time or
another, and Swiss watches and knives are pretty neat.
Hmmm, actually, that may be the Swedes who monitor cow flatulence; I apologize for my Swiss-Swede
dyslexia. I am pretty sure the K31
belongs to the Swiss and people who like guns seem to really love
these rifles. I had a bunch of test equipment and three rifles laying on the bench at the range
this afternoon; a K31 chambered for the 7.5x55 Swiss, a Ruger No. 1
45-70 Gov't and a BLR Browning in 243 Winchester. All morning and
afternoon I had visits only from people who wanted to talk about C&R
licensing or K31's.
I've been building and buying firearms for a
considerable period of time, but it had been quite awhile since I
spent time with unaltered military firearms, since my teens to be
more precise. Several months ago I picked up a few surplus pieces
for various projects, all remained intact, one was refurbished, all
became good shooters and the object of a handload development
effort. I got in the habit of checking the newspaper for military
surplus sales, mostly those sold by a local Big 5 that is gun
friendly. The only piece I had avoided was the K31. I had somehow
gotten the notion in my mind that they fired an anemic round and the
straight pull action and key chain loop at the end of the bolt were
quirky enough to dampen my enthusiasm for the rifle.
Eventually Big 5 ran out of Enfields, and Springfields,
and Mosins, and Mausers even of Turkish descent. It was a long weekend,
nothing on TV, so I bought one, then immediately made the mistake of
trying to buy a box of ammo. I think the response was, "You're going
to love this gun. I normally have ammo on hand, but for some reason
I don't see any behind the counter right at this moment." Right,
this or any other moment. The cartridge is the 7.5x55.6mm (GP 11)
which, I learned, is Swiss for "On perpetual back order".
I set out to buy brass on the Internet and a set of
dies so I would be able to handload whatever I needed. Finding
brass on backorder for several months, I instead located reasonably
priced FMJ non-corrosive and reloadable
cartridges and Hornady New Dimension Dies at Graf & Sons, and a
copy of "For Collectors Only. Swiss Magazine Loading Rifles 1869 to
1958" from Amazon.
takes me awhile.... bits and pieces
I like to purchase firearms, then figure out what I
bought. With the rifle semi clean and laying in my lap, I began
reading, identifying and pointing to it's various parts in an
attempt to identify something about the gun's history. If you'll
excuse a little gratuitous "blah, blah" - the K31 is not a Schmidt in the strict sense of the
word, it is a redesign by a Major Furrer on the Schmidt-Rubin Model
1911, and actually quite an improvement; it is shorter. lighter and
better balanced. The particular rifle I purchased weighs 9 1/2 lbs,
is 43 1/2" long and has a 12 3/4" pull - chunky. Trigger pull is a
clean 4.6 lbs from a trigger that is reminiscent of a screen door
latch that moves in a long exaggerated arc. The
bolt cycles like a large, heavy, well oiled machine; very smooth
throughout its travel and with substantial heft. According to serial number dating,
this particular K 31 was
manufactured in 1944; a busy year in Europe, however, apparently not too busy
for Eidgenoessische, Waffenfabrik, Bern, Switzerland to produce
approximately 51, 899 K 31 rifles. The K31 was produced in total
between 1933 and 1958.
Nice to have a surplus rifle that isn't back bored.
The K31 has a nicely recessed grown that is intended to protect the
muzzle terminated surfaces of the bore. The 4 groove K31 barrel is
approximately 26.450" in length, the twist rate is about 10.6". I
have seen several minor variations on these dimensions, most I
assume the product of various millimeter to inch conversions. The
bore of the rifle I purchased is better than most of my commercial
rifles, including those costing 20 times more. I understand these
rifles only saw non-corrosive ammo, still, 60 years is a long time for
a rifle to remain in such good condition.
The spec caliber of the K31 is 7.51mmm, which is
somewhat problematic as there is no conversion relationship that
will get you to the actual 306" groove or 308" bullet the rifle utilizes.
The original chamber pressure spec for the K31 cartridge is
3200 bar or 46,000 PSI. The current CIP spec for the 7.5x55mm GP11
Swiss cartridge is 3800 bar or 55,000 PSI. Spec velocity is
approximately 2600 fps with a 174 grain bullet, performance easily
surpassed with safe handloads.
The front sight, pictured right, has
inward curved protecting ears which is consistent with a K31, the
similar but earlier Model 1911 ears are splayed outward. Notice the stake mark that anchors the sight
blade to the sight assembly, I don't think anything is going
anywhere accidentally. In terms of adjustment, 1 mm of front sight
horizontal adjustment shifts point of impact 12 cm at 300 meters.
Front sights blades were produced in 5 different mm heights: 5.9,
6.2, 6.5, 6.8 and 7.1. The incremental change in vertical point of
impact at 300 yards is 16 cm. One thing that I always find odd about
military rifles is the sight adjustment as received. I worry about
checking my rifle's sights when it has not been used for a while, or
certainly after it had been shipped. After all, this bouncing around
surely should cause sights to move. The K31 was cleaned and taken to
the range with no further adjustments and shot dead on at 100 yards,
windage and elevation. My Russian rifles also shot the same.
The absence of range
markings on the rear sight base indicates it is a K31 type and consistent
with the 1944 production date. The sight's range of adjustment is 100
to 1500 meters, indexed in 50 meter increments. Unlike the rear
sights on my Turkish Mauser, the pieces don't rattle around, they lock up well and are solid in use.
Other identifying items like finger
groove offset, trigger guard and butt plate size, shape and
placement all track to a K 31. I
removed the butt plate looking for the owner identification
information that is sometimes found, however, all
I found was a date stamp for the stock, October 1948, which suggests
the gun was refurbished or fitted with a replacement stock. The
stock is not walnut, it is birch, which would be consistent with the
"X" and "1948" stamps. I'm not worried about the lack of stock originality. I'm
not sure when the change to this particular gun was made; could have
been at Century Arms, could have
been in 1948, but it still looks OK and better than a replacement of
modern manufacture. A quick check of a replacement walnut utility
grade stock found a $159 price tag for stock and handguard, with a
lot of fitting work required. With that additional information I, of
course, grew to appreciate the near authentic looks of the stock
that came with the $89 rifle even more.
There are a few unique external aspects of the
K31, in addition to the straight pull operation. 1) Bolt release, 2)
Cam follower handle, not bolt handle, 3) cocking ring, 4) stripper
clip, or charger, cut out in receiver.
The bolt is removed by pulling it rearward, then
depressing the bolt release latch. The cam follower does not serve
the same purpose as the bolt handle on a classic turn bolt
rifle and is therefore not called a bolt handle. A bolt handle is
affixed to a bolt body and rotated the body to lock and release
locking lugs. In this straight pull scheme, the cam follower rotates
the bolt's locking sleeve and lugs, camming them into position. The cocking
ring, when the rifle is cocked, can be rotated clockwise to obstruct
forward travel of the cocking piece sear and lock the bolt in the
closed position; the safety.
As the straight pull operation is the central theme
of this firearm, I thought I would take a few moments to provide a
little more detail and see if I can't confuse everyone. The cam
follower provides a couple of functions. The cam follower pin (2)
travels in the bolt locking sleeve's helical groove. Pushing the
follower forward carries the bolt assembly forward in the action
while rotating the locking sleeve and locking lugs (4) clockwise
into the receiver's locking lug slots, Pulling aft on the cam
follower reverses the direction of the locking sleeve, pulls the
lugs out of the locking lug slots and releases the bolt. The cutout
at the end of the follower (3) prevents the bolt from being removed
from the rifle until the spring loaded bolt release latch is
depressed and clears the cutout.
The operation isn't actually that weird, although it
takes a little adjustment to overcome turn bolt operation
tendencies. If you've shot a Browning lever gun you will find a
similar rotating bolt sleeve and locking lugs that translate the
fore and aft motion of the operating lever to the rotating motion of
the bolt's locking lugs. The assembly cocks on opening.
The K31 was one of several military rifles produced
with a straight pull action. Other notables are the preceding
generations of Schmidt-Rubin rifles, Canadian Ross, Winchester Lee
and Steyr Mannlicher M95. It is hard to say what exactly the
straight pull has to offer. Speed of follow up shots is the first
suggestion typically put forth, followed by smoothness of operation.
The first draw back referenced is that the straight pull does not
have the mechanical advantage of a turn bolt action, the second is
that the straight pull is based on a more complicated mechanical
Personally, my sentiments are: the action is very
smooth, I can't feel a practical speed advantage, I can't see where
the assembly is much more complex than a turn bolt gun with its own
complex innards. In the court of public opinion the Swiss rifle is
the only straight pull that endured for so long as a military
weapon, the others fell by the wayside as the weapon of choice for
armies that actually saw combat, the Swiss version never did. People
with their lives on the line, on critical missions, tend to shed the
fluff and go with the essentials. So what's the point? I think
anyone looking for blinding speed or bench rest accuracy as a result
of straight pull design may be disappointed in the K31. Anyone
interested in well made Swiss machinery, better than average
accuracy and something unique in operations will find themselves
pleased with the K31.
Most K31s of this vintage have hellacious scratches
that run from the butt plate upward about 4" and mine is no
exception. There really is no mystery, the marks are the results of
soldiers drilling with hob nailed boots. I have seen illustrations
of the drill, and the boots and the results. What does this mean?
Only that most of these great looking rifles are diminished in
appearance by abusive handling. I may try to sand some of them out,
but probably not. There isn't sufficient material above the sides of
the butt plate for refinishing and the cost of a replacement stock
is prohibitive, or at least not practical. The balance of the wood,
and certainly the metal parts are in excellent shape with barely
signs of wear.
The K31 holds 6 rounds in its detachable, the mag is
easy to insert and remove. The bolt will not close on an empty mag
unless the shooter depresses the mag follower while pushing in on
the bolt...which may result in the Swiss version of the M1 Thumb.
Check out the trigger. That has got to be the longest
trigger I've ever seen. For me, pull isn't so great, but I may just
need to practice more with the rifle. It is smooth, but it feel
springy and too lightly sear loaded.
The trigger guard is Swiss practical, or stamped
steel cheap, depending on your perspective.
equipment problems beyond my control, and an errant software
setting, I was able to spend more time than intended with the K31.
Shooting it was an interesting experience. The first shot missed the
target. What I thought was a nick in the rear sight was actually the
notch for aiming, and that slightly left listing post up front was,
in fact the sight blade. One I had that sorted out, even with less
than stellar eyesight I was able to shoot inch to inch and one half
3 shot groups at 50 yards. For my open sight skills and off the
shelf cheap ammo and an unfamiliar rifle, that's pretty good. In
fact, I was impressed.
There was very little recoil. The short pull and full
length stock with handguard gave the gun a slight nose heavy feel;
steadying more than uncomfortable in balance. The action was slick
in use and fed and extracted without a hitch. The only thing I
noticed is that the bolt needs to be opened firmly or there is the
chance of an empty flipping over in the action and not ejecting.
That only happened once when I was trying to cycle more easily to
avoid chasing empties around behind the firing line.
The Prv Partizan ammo appeared to be very good
quality Serbian production. These cartridges have boxer primers,
non-corrosive and, at $14/box, not all that expensive to shoot. This
particular load is 174 grains FMJ BT with a MV of about 2600 fps.
Sounds familiar? They are also producing a soft point load, however,
it is relatively new and I found none in stock. Hornady and
Graf&Sons is loading a soft point also, for about $5 per box more.
My primary purpose for getting ammo was to eventually get empty
Of the non-U.S. military surplus rifles I've been
able to shoot over some period of time, this one ranks second to the
Model 38 Mosin Nagant in entertainment value, although the K31 has
an edge in accuracy, but not a huge edge. I'm looking forward to
handloading some ammo and seeing what I can wring out in
ballistic performance and consistency. I'm thinking 165 grains at
2900 fps without exceeding pressure specs. We'll see.
There are scope mounts for the K31; a right side
clamp on from St. Marie
Graphics, a left side drill and tap from the same, and one of the
mounts that hangs on the rear metallic sight mount. None of these
looked very appealing or in anyway similar to the scoped version of
the K31 and none are in the cards for this particular gun. I think
the metallic sights are fine for any use the gun might see, including
eastern U.S. hunting although I wouldn't relish the thought of
dragging this one around in the woods.
The K31 is a very nice military surplus piece and an
excellent bargain. The specimens I've seen are in much better shape
that other popular models sold through discount C&R dealers or
retailers, particularly bore condition and metal finish. Stocks are
a bit ratty, but functionally fine if they are not cracked. Because
of their accuracy and solid feel K31s are enjoyable to shoot and the
7.5 Swiss is a pretty potent cartridge. The down sides are weight,
inability to easily and properly mount a scope and lack of sporter
potential for those who might be so inclined. It is a strong action,
but I would not want to crank this one up; two locking lugs and a
straight pull action. The gun actually has not much of a history. It
saw no combat, so it's value was not proven under survival
circumstances. Basically, it was the weapon of choice of an army
that never went to war. I think some folks have unjustifiably
elevated this relic to almost mystical levels with unfounded stories
of Swiss precision and unrealistic tales of accuracy. It is a $89
rifle, if it didn't have a lot of compromises and limitations in
use it would be a $500 milsurp rifle. Still, in the land of
affordable imported relics, I would rank it the best of the readily available
military rifles out there.
More K31 info on Real Guns:
7.5x55 Swiss Handloads
7.5x55mm Swiss Handload Data