Hello all.

How is the K31 Swiss straight pull action?
Strong? It looks odd and also cool, so the idea of one on a hunting rifle is tempting.
Anyone who use it?

quote:

Originally posted by vegard_dino:
Hello all.

How is the K31 Swiss straight pull action?
Strong? It looks odd and also cool, so the idea of one on a hunting rifle is tempting.
Anyone who use it?

My K31 has become my favorite carry around deer and hog rifle:



Its all matching with a tag, walnut stock and a great barrel. That scout scope mount is a S&K, which can be removed and the rifle put back to original. K31s typically are accurate, have a great trigger pull and the action is strong - Mine's no exception.

However, I've seen very few restocked and sporterized K31 and the ones I'ves seen were not very attractive to me! So...few cautions:

1) If you have a good K31 best the keep it that way! If not then -
2) The top of the receiver doesn't have much metal thickness for drilling and taping a scope mount. And I don't personally like the looks of a side scope mount.
3) Of the ones I'ves seen restocked, the look and lines of the after market stock just aren't attractive. Be attentive to the look and lines!

If I wuz gonna build one, I'd start by finding/fabbing a new trigger blade and trigger guard. Secondly I'd remove or otherwise disguise that big honkin' ring on the bolt's rear. Re scope mounts, there are 50 ways including soft-soldering to the thin receiver.

The profile is a little blocky but the QUALITY is superb!
Regards, Joe

Thanks for the reply and info.

What kind of loads do you use Ray?
A nice looking gun you got.

I will give my opinion on the K31, something that surprises me that any poster from Switzerland would be asking.

The K31 rifle is very different from the Mauser based rifles which Americans are familiar. One difference is the bedding. The recoil lug is the trigger housing on the back of the action.

You Swiss machined a very expensive rifle, a bud of mine pointed out elliptical machining cuts, something he was baffled on how to do. I have been told that all bolts across the twenty years of production are interchangeable. That is amazing.

My K31’s shoot very well for a service rifle, I really wish the Swiss Army had put a windgage on their rear sight.

I conducted some load development for the 7.5 Swiss. I have never purchased Swiss ball, but a bud gave me a chance to shoot some across my screens.

AA4350 gave excellent accuracy and just about duplicates Ball velocities with 51.0 grains and a 168 Nosler Match bullet. As you can see 52.0 grains produced velocities over Ball, so I do not recommend that load. It is here for reference.

Instead of AA4350 I am shooting surplus WC852 in the 7.5 Swiss. This is a ball powder, and I purchased my lot from Jeff Barlett at GIBrass.com . It turns out Accurate Arms purchased a 90,000 pound lot of WC852, faster burning than Jeff’s lot, and now it is labeled as 2700. My lot of WC852 shoots extremely well, was dirt cheap, and I am using that up. But if I did not have the surplus powder, I would give IMR4350 or AA4350 a go as it shot very well.

7.5 x 55 Swiss Model K-31

AP11 Swiss Ball headstamp DA 78
24 Mar 04 T = 70 ° F


Ave Vel = 2565
Std Dev = 11
ES = 23
Low = 2551
High = 2574
N= 4

168 gr Nosler Match 51.0 gr AA4350 INDEP brass and primer OAL 2.850
22 Dec 01 T = 58 ° F
Ave Vel = 2536
Std Dev = 17
ES = 45
Low = 2510
High = 2555
N= 9


168 gr Nosler Match 52.0 gr AA4350 INDEP brass and primer OAL 2.850
22 Dec 01 T = 58 ° F
Ave Vel = 2624
Std Dev = 31
ES = 72
Low = 2588
High = 2660
N=5



I have not tried putting a grease ring around my bullets, I read that Swiss target shooters found greased bullets shot more accurately than non, and 1978 and earlier swiss ball has the grease ring.

Note: Hatcher claims this "dangerously" raises pressures. Hatcher lied!

I have several K31's and would never sporterize one of them. Mine are very accurate and Graff and Sons sell a scope mount that clamps on the side with no alterations to the rifle.

Thanks all for the information.

The K31 is a interesting rifle. MAybe have a look and se if I can find one for sale here.
The caliber is also a good one for deer, wild boar and so.

quote:

Originally posted by vegard_dino:
Thanks for the reply and info.

What kind of loads do you use Ray?
A nice looking gun you got.

I got some new cases from Grafs.
Reload both the 165 and 180 SGKs using IMR-4350.

Thank you for the reply and information.

http://picturearchive.gunaucti...94e883d98f0e45d8.jpg

not mine

The K31 is a beautifully made battle rifle as mentioned already. Couple things to keep in mind. The chamber has a relatively short, tight throat which can affect seating depth and which cast bullets will work. A straight pull bolt does not provide a lot of primary extraction leverage. If you get enthusiastic with your reloads, you can end up with sticky extraction before you would in a regular bolt rifle.
Get the newer dies from Redding or RCBS that are better sized to the K31 chamber. They don't work the brass as much and you gain significant volume and velocity closer to the 30-06 than the .308win.

I tweaked the trigger and bedded one of my K31's and with the detachable Swiss target sights it will run neck and neck with my Krieger barreled target rifles.

There are several forums that deal specifically with the Swiss rifles. The GP11 ball ammo is hard to equal for target shooting.

Interesting.
Thanks for posting.

One of the secrets of the legendary accuracy of K31 is that the barrel is free floated. But if the front band is too tight, that will negate benefits of free float. Simple way to deal with this is to remove little wood inside the stock behind the muzzle, where front band is. (Can be done with sandpaper). Also do not tighten front band screw. As far as the scope mount, Swiss Products makes excellent side clamp-on mount for regular eye relief scope. There is a guy who builds top grade scope bases, he will tap and drill your action and install it. Google rock solid industries. The quality is on par to the the rifle itself. that. There is nothing wrong if sporterized tastefully.

The other big thing to keep in mind if building a custom rifle off the K31 is that a caliber change is not easy. The barrel has some complex cams cut into the face that I have yet to see duplicated by a gunsmith. The rifles that I am aware of that have had the barrels changed to a different caliber or chambering, use the original breach end of the barrel as a bushing which is bored out and threaded to accept a new barrel. A re-bore should be possible if going to a larger caliber as well. But, the 7.5x55 is an excellent cartridge for most game except the big stuff in Africa.