Swiss K31: Stunning

[ptosis]

Years ago I disassembled 10 rounds of GP11. Measured bullet weight, ogive, powder charge. case, overall weight, neck concentricity etc.

For mass produced ammo, it's darn near a hand load in consistency. At least the lot that I measured. Pretty impressive as it's typically referred to as "surplus".

Indeed, the standard deviation of muzzle velocity of 1990s production GP11 is typically between 4 and 4.5 m/s (13-15 fps), depending on the batch, and with a match barrel it typically stays within the 10 ring of ISSF target at 300 m (10 cm); in Switzerland the ammo is routinely used for 300 m CISM/ISSF standard rifle competition.

For a bulk military issue cartridge, GP11 is insanely well done.

BTW, RUAG restarted the GP11 production lines in 2017, after more than 20 years break. This new production is just as good as the old one (and, regretfully, it is still berdan-primed).

 

[Spicerack]

Finally added one to my safe. 1943 serial number. Now to find some ammo!

 

[sandwarrior]

Finally added one to my safe. 1943 serial number. Now to find some ammo!
View attachment 7842534

Haven't seen any real GP-11 for years. Your best bet is to reload. As mentioned by Pierre, 175 SMK's work well. Graf's has PRVI bullets that match your needs. If not quite as accurate, they do have a great BC.

If you do not have reloading capabilities find someone who does, and work with them to get rounds loaded.

 

[Spicerack]

Was going to jump on a case of Prvi from SGammo, empty the brass the fun way, then reload that brass.

 

[Ledzep]

I've also gotten away with resizing .284 win brass. It matches the body diameter, and so far I've had decent success with the rebated rim working with my rifles. It's not as solid as the full diameter rim on dedicated brass, but it works and is often easier to find.

 

[Calfed]

Finally added one to my safe. 1943 serial number. Now to find some ammo!
View attachment 7842534

Beautiful rifle!

SG Ammo has some Prvi 7.5 Swiss in stock.

7.5 Swiss Ammo | SGAmmo.com

Shop at SGAmmo for 7.5 Swiss Ammo. We carry a wide variety of affordable and high quality ammunition ready to order. We're selling bulk ammo at discount prices. Buy now!

www.sgammo.com

Edit:
Ooops...just noticed your subsequent post.

 

[Winchester M70 Van Orden]

Good evening, Chancellor,

A very well description of your experience !
And welcome to the Schmidt-Rubin-Carbine and Long Rifle-Family

Regards from the Alps

 

[Davo308]

Wish I could find some berger 174s so I could pull some gp11 down and seat them in the gp11 case.

I don't want to spend 35 bucks for 20 ppu rounds.

Also heard berger stopped making those bullets

 

[kujuak]

Wish I could find some berger 174s so I could pull some gp11 down and seat them in the gp11 case.

I don't want to spend 35 bucks for 20 ppu rounds.

Also heard berger stopped making those bullets

Berger 175VLD target bullet is bullet I think closely matched GP11 bullet. It has been discontinued. I have a few boxes but could not rationalize searching for more old stock given lack of long term availability.Under 300yds no particular advantage for these expensive bullets so I'm saving them for playing at long distance. Luckily I was able to get a bunch of GP11 on sale back in the day at $200/case.Working on shooting it up before it goes bad. One of my Swiss beauties.

 

[Calfed]

Wish I could find some berger 174s so I could pull some gp11 down and seat them in the gp11 case.

I don't want to spend 35 bucks for 20 ppu rounds.

Also heard berger stopped making those bullets

I'm not sure how much improvement you could get by replacing the GP 11 projectile.

These are 175 gr Nosler CC, Sierra MK, Barnes Match Burner, and the GP11 projectiles. I think the Barnes MB is similar to the Berger

 

[Calfed]

Nosler has a line of Reduced Drag Factor "RDF" bullets out. I picked up some of the 175 gr .308 RDF's. Very similar to the Barnes Match Burners.

I noticed the meplat is much smaller and more uniform than other .308 175 gr match bullets.

Various 175 gr .308 bullets...

Sierra MK, Nosler Custom Comp, Barnes MB, Nosler RDF

 

[Davo308]

I'm not sure how much improvement you could get by replacing the GP 11 projectile.

These are 175 gr Nosler CC, Sierra MK, Barnes Match Burner, and the GP11 projectiles. I think the Barnes MB is similar to the Berger

The problem is with the GP11 bullet...the local ranges hit it with a magnet and declare its steel core.

When I point out its a cupro nickel jacket and that it's magnetic their eyes roll back.

My favorite is when they say drive the 1 1/2 hour drive to the range so we can tell you you can't shoot GP11.

 

[Calfed]

The problem is with the GP11 bullet...the local ranges hit it with a magnet and declare its steel core.

When I point out its a cupro nickel jacket and that it's magnetic their eyes roll back.

My favorite is when they say drive the 1 1/2 hour drive to the range so we can tell you you can't shoot GP11.

That is a good point. In the absence of Berger 175 VLD's, I think the Barnes and Nosler RDF's are as close as you can probably get to the GP 11 projectile.

 

[ptosis]

The original GP11 projectile has a G7 BC of 0.274; that's what one should aim for to reproduce the original external ballistics. If my memory is good, Hornady has something 175grain-ish with a very similar BC.

This said, the projectile has evolved over the years (I could never find any documentation, but the ballistic tables for the K31, the Stgw 57 and Ruag doppler data are not exactly the same), and the K31 iron sights elevation is a little bit too pessimistic for the recent production ammo.

 

[Tempest 455]

I've shot GP11 out to 1K many times. Being F class person, I would not call it super accurate.
However, it's pretty killer at 600 yards for surplus with irons.

 

[Davo308]

I've shot GP11 out to 1K many times. Being F class person, I would not call it super accurate.
However, it's pretty killer at 600 yards for surplus with irons.

I'm hoping with a good target scope I can get out to 800.

Figure a projectile that stays supersonic to 1k will have an easier time at 600/800 yards.

It's one reason I'm looking at the 169 grain smk, which is intended to increase tran sonic performance of .308 bullets.

 

[Davo308]

I'm hoping with a good target scope I can get out to 800.

Figure a projectile that stays supersonic to 1k will have an easier time at 600/800 yards.

It's one reason I'm looking at the 169 grain smk, which is intended to increase tran sonic performance of .308 bullets.

Also I have added about 3 lbs of weight to the K31(all reversible) and a compensator.

I'm hoping this cuts down on stresses to the 72 year old stock.

The scope is Frank approved...

Weaver Tactical Grand Slam Rifle Scope 3-10x 40mm 1/10 Mil Adjustments

The Weaver Tactical Grand Slam Rifle Scope offers fully multi-coated Japanese lenses that reduce glare and give you edge to edge clarity and exceptional...

www.midwayusa.com

ShootersCalculator.com | Ballistic Trajectory Calculator

Calculates the ballistic trajectory of a bullet fired from a rifle, handgun or other firearm. Produces a ballistic trajectory chart and table that shows the drop, velocity, kinetic energy, windage, and trajectory of a bullet.

www.shooterscalculator.com

 

[Calfed]

Also I have added about 3 lbs of weight to the K31(all reversible) and a compensator.

I'm hoping this cuts down on stresses to the 72 year old stock.

The scope is Frank approved...

Weaver Tactical Grand Slam Rifle Scope 3-10x 40mm 1/10 Mil Adjustments

The Weaver Tactical Grand Slam Rifle Scope offers fully multi-coated Japanese lenses that reduce glare and give you edge to edge clarity and exceptional...

www.midwayusa.com

ShootersCalculator.com | Ballistic Trajectory Calculator

Calculates the ballistic trajectory of a bullet fired from a rifle, handgun or other firearm. Produces a ballistic trajectory chart and table that shows the drop, velocity, kinetic energy, windage, and trajectory of a bullet.

www.shooterscalculator.com

That is a nice scope. A few years ago Natches was blowing them out and I grabbed myself a few. Nice glass, repeatable adjustments, made in Japan.

 

[Davo308]

That is a nice scope. A few years ago Natches was blowing them out and I grabbed myself a few. Nice glass, repeatable adjustments, made in Japan.

I like how its mil/mil and I picked up a new in box for 200.

Just wondering if the lack of parallax is bad and would like another 10 moa adjustment range.

I found some links to making a defacto zero stop as well.

As it is it should get me to 800 maxed out but realistically 600 meters/650 yards will be as far as I plan to shoot.

 

[Calfed]

I wondered about the lack of parallax adjustment, but note that many scopes in that power range do not have that feature

 

[Calfed]

Swiss Products has long made a clamp-on Scope mount for the K31. The problem is that it mounts the scope to the right side of the bore axis. They have now alleviated that problem with an add-on that places the scope over the bore axis.

Product Page | swissproductsusa

www.swissproductsusa.com

 

[ptosis]

Swiss Products has long made a clamp-on Scope mount for the K31. The problem is that it mounts the scope to the right side of the bore axis. They have now alleviated that problem with an add-on that places the scope over the bore axis.

Product Page | swissproductsusa

www.swissproductsusa.com

Looks good, thank you!

This said, judging by the photos, it should be coming with a ~50mm cheek riser in the kit.

 

[TorF]

Has anyone tried the Swissproducts sidemount rail for left side of the receiver?
This mount will place the scope in the same position as on a Garand Sniper.
With a Garand sniper cheekrest and this sidemount, and with a scope in low rings, I think this would be a very good compromise. No need to move head away from the stock to avoid the bolt hitting the head during reloading.

 

[M77]

Shot a Service Optic match a few months ago with the K31, man its such a sweet rifle to run. I will end up using a better sling for unsupported shooting but I was just happy to shoot the thing.

 

[Winchester M70 Van Orden]

Berger 175VLD target bullet is bullet I think closely matched GP11 bullet. It has been discontinued. I have a few boxes but could not rationalize searching for more old stock given lack of long term availability.Under 300yds no particular advantage for these expensive bullets so I'm saving them for playing at long distance. Luckily I was able to get a bunch of GP11 on sale back in the day at $200/case.Working on shooting it up before it goes bad. One of my Swiss beauties.

A beautiful looking

A Leupold Scope. Which magnification and reticle do you use, If I may ask ?

Comparison between the GP 11 and newer bullets: thats my impression too. At distances until 300 yards that seems to be the usual experience. The ranges above 300 yards are another chapter. Fine choice of bullets you have in the States... . And you may reload our GP 11-Cases. That makes the reloading really easier. Here that is forbidden for civilian use.. .

A bunch of GP 11 on sale: that sounds good. Which year of production is it ?
(I hope, you all know that the GP from the production-year 2016 and newer has caused serious trouble in our 3 Service-Rifles Assault-gun 57 resp. Stgw 57, Karabiner K31 and Long-Rifle G11 ?) In contrast to the older productions.. . A CH-Gunsmith warned me explicitly recently.

 

[ptosis]

That makes the reloading really easier. Here that is forbidden for civilian use.. .

Shooting a k31 is allright, but reloading GP11 brass is not? Here = where?

(I hope, you all know that the GP from the production-year 2016 and newer has caused serious trouble in our 3 Service-Rifles Assault-gun 57 resp. Stgw 57, Karabiner K31 and Long-Rifle G11 ?) In contrast to the older productions.. . A CH-Gunsmith warned me explicitly recently.

Hearsay. Ruag and the army have done a very, very serious study based on these claims, and have factually refuted all claims in that sense (which, by the way, perfectly matches the results of my own tests of old vs. new production -- no perceptible difference in precision or muzzle velocity SD).

The only confirmed problems involved standard/free carbines chambered in 7.5, and aftermarket heavy barrels for the Stgw.57 (did I hear G&E?), because, in a pursuit of ultimate precision, chambers were off-spec (done to the size of the production brass rather than to the CIP min. size).

Any ordnance barrel shoots the new GP11 just fine.

 

[Clark]

Tags under my K31 butt plates.

 

[fa38]

Davo, maybe I can clarify.
Haemmerli made a number of new k31 runs before they closed their doors forever sometime around 1999 to 2001. Can't remember for sure. OGS is with me more often than not these days. The serial number will be preceded by a "P", signifying Private, however........... It's often confused with the "P" stamped on service k31s that were offered to soldiers mustering out after service that opted to keep their rifles.
The easiest way to tell the difference is that the Haemmerli Private rifle "P"s are the same font, thickness and in perfect alignment with the serial number, all in one stamp. The mustering out "P" is almost never the same thickness or perfect alignment with the serial number and is obvious it was stamped after the fact.

I have what you describe as a mustering out P marking on my K31. How do they stamp the receiver if the receivers are so hard. Do they have to support the receiver with something replacing the bolt? Mine appears to have been someone's match rifle with the two tape markings one red the other yellow. I have never shot mine with service ammo. It has been my cast bullet match rifle and it shoots very well.

 

[zfk55sr]

Good morning. Actually I spent a lot of time this morning reading through all of these posts, and I quite enjoyed it. It's far too much for me to comment on, but as for the left side drill and tap mount, I still have that on my old hunting K31. I developed that mount sometime in the early 80s to replace the cheap bent metal mounts that came on the G11 series imports from Golden State arms and Santa Fe arms. The 5 drilled holes in our mount will accommodate all three of the importers that converted the G11 series to .308 or those left in the original caliber but sporterized.

As for the stamping of the mustering out P, I am clueless, but the strike does seem to be a bit shallower than the serial number. The case hardening on the receiver is what it is, and how that was accomplished considering the hardness, is beyond me. I can tell you that Haemmerli used the same receivers that they obtained from Bern when the factory stopped production.

They put that same "P" in front of their serial numbers on the private, or commercial rifles they made during the 50s, designating them as a private run, and I believe it was right up into the 60s.
As I remember, they closed their doors in 1995.

Once again, great reading on this entire thread and, also once again, far too much for me to comment on, but I did enjoy it.

 

[fa38]

I am surprised more people are not shooting the K31 with cast bullets. The main matches at the Cast Bullet Association military matches are shot at 100 and 200 yards. The Springfield pattern 03’s and 03-A3’s and the K31 are the most used rifles. The matches are shot with the reduced 600 yard military target at 100 (mr 31) and 200 (mr 52) yards. 20 shots at each yardage and scores in the 390 plus are shot with both rifles usually with scopes 6x max power. Recoil is a lot less with them lead bullets. Hope this is not too far off topic.

 

[zfk55sr]

Actually, it might surprise you how many of the members on different forms and on the Internet Swiss rifle pages actually do shoot cast loads. I'm one of the cofounders of Swiss rifles . com some 21 or more years ago, and in the reloading section you will find a lot of people that both shoot them and hunt with them.

 

[Halfnutz]

I am surprised more people are not shooting the K31 with cast bullets. The main matches at the Cast Bullet Association military matches are shot at 100 and 200 yards. The Springfield pattern 03’s and 03-A3’s and the K31 are the most used rifles. The matches are shot with the reduced 600 yard military target at 100 (mr 31) and 200 (mr 52) yards. 20 shots at each yardage and scores in the 390 plus are shot with both rifles usually with scopes 6x max power. Recoil is a lot less with them lead bullets. Hope this is not too far off topic.

I've heard more than one person say 7.0gr of Unique under a cast boolit is the ticket. (using the right methods)

 

[zfk55sr]

Please don't take that kind of advice literally or simply. There's more involved than that.
One single aspect of a rifle case with a small charge laying along the bottom of the case, is its not going to perform like a similar load with a filler ahead of it. The burn rate is completely different, as will be the performance down range.
You need to find a forum on reloading cast projectiles and seek the advice of experienced reloaders in that mode.

 

[fa38]

My load which shoots in the 390's is 16.0 grains plus or minus a couple of tenths with different lots of 2400 with a RCBS 165 gr Sil gas checked bullet seated so that the ring just to the front of the nose is seated just barely out of the case. Seated longer the bolt is hard to close and the cure for that is too hit the bolt handle again and shoot the bullet into the berm because its not going where it was aimed. Pulling the bolt open will dump the powder into the action because the bullet is stuck in the rifling. It took two times for that to happen for me to learn that lesson. Slow learner.
One of our match results. No more matches at our club and a 4 to 5 hour drive to the closest.

https://castbulletassoc.org/uploads/documents/318/vandyne08092014.pdf

 

[ptosis]

The K31 magazine I always wanted (and ended up making, because nobody else would).
That's the final prototype; production runs to hit the Swiss market in Q1 2023.

 

[Ledzep]

That's awesome! Any plans/ability to get them over the pond?

 

[zfk55sr]

Very good looking. Are these steel or are they 3D? I remember 35 years ago I priced the equipment necessary to manufacture these magazines and the custom bending system was going to cost me $35,000, so we passed on it. We have a lot of CNC's, but not the one that fabricates the multiple bend requirements.

 

[ptosis]

That's awesome! Any plans/ability to get them over the pond?

Thanks!

Indeed, considering the number of K31s in circulation in the US, that might be interesting. First, I'll get the production rolling, then I'll have some material to speak with dealers who export to the US; will keep you posted here.

 

[ptosis]

Very good looking. Are these steel or are they 3D? I remember 35 years ago I priced the equipment necessary to manufacture these magazines and the custom bending system was going to cost me $35,000, so we passed on it. We have a lot of CNC's, but not the one that fabricates the multiple bend requirements.

Thanks! It's all old-school sheet metal, stainless steel (except the polymer CNC follower). Respecting the memory of Adolf Furrer, I would not settle for less (and the PVD coating is likely to be more abrasion-resistant than the original oxidising).

It's true that tooling costs are very unpleasant, and in today's CNC-machined world it was very hard to find people who still know how to work sheet metal for anything more complex than a square 90° fold electronics enclosure.

 

[ptosis]

Specs and more photos: K31-XXI 10-shot magasine
(Hope I am not going to get banned on SH for unapproved commercial advertisement.)

 

[zfk55sr]

At the moment, I suspect you will find a market in the US.
Best of luck, my friend!

 

[ptosis]

At the moment, I suspect you will find a market in the US.
Best of luck, my friend!

Tanks a lot for your encouragement! I have really put a lot of thought, time, and effort in this piece, and I really hope it will encouter the success I think it deserves.

 

[lariat]

Thanks! It's all old-school sheet metal, stainless steel (except the polymer CNC follower). Respecting the memory of Adolf Furrer, I would not settle for less (and the PVD coating is likely to be more abrasion-resistant than the original oxidising).

It's true that tooling costs are very unpleasant, and in today's CNC-machined world it was very hard to find people who still know how to work sheet metal for anything more complex than a square 90° fold electronics enclosure.

Yeah the CNC world is hurting for the knowledge we have lost in the last decades. Did you look into the possibilities of a press with progressive or even single stage dies? Not cheap but volume pays for things pretty quick as long as you buy only the size you need. Anyway, that’s some nice work there.

 

[1588]

Please don't take that kind of advice literally or simply. There's more involved than that.
One single aspect of a rifle case with a small charge laying along the bottom of the case, is its not going to perform like a similar load with a filler ahead of it. The burn rate is completely different, as will be the performance down range.
You need to find a forum on reloading cast projectiles and seek the advice of experienced reloaders in that mode.

I've chronographed light loads with and without filler in the cases. Velocities were drastically different and there were pressure signs on the cases where fillers were used. I settled on not using a filler when loading cast bullet reloads for 30-06, 8MM Mauser and 45-70.

The biggest risk in loading cast bullets with pistol powders is dropping too much powder in the case. If you are careful, you can safely load a cast bullet that will shoot sub 2 MOA groups at 100 yards.

 

[LargemouthAss]

Any updates on when the new manufacture GP11 will be in the states?

 

[Calfed]

Specs and more photos: K31-XXI 10-shot magasine
(Hope I am not going to get banned on SH for unapproved commercial advertisement.)

Any update on these magazines?

 

[ptosis]

Any update on these magazines?

Coming soon. One of my suppliers has messed up critical dimensions on a part, so the whole batch needs to be redone, and that takes a few weeks.

Release to the Swiss market is scheduled for end-March / beg-April, immediately shippable to EU/Schengen countries.

Then I'll see about exporting to the US, maybe for the end of summer; in an officially neutral country, this might be a bit of an obstacle race, but apparently nothing's unsolvable.

 

[ptosis]

Any updates on when the new manufacture GP11 will be in the states?

Probably never. The old GP11 was exported because there was a huge surplus in the army stocks (enough to hold a long nuclear winter), and it was approaching the limits of shelf-life.

The new production is running much more more tightly -- to satisfy the demand of the army and of militia shooters; the last batch we got was from 2018.

 

[kujuak]

I am surprised more people are not shooting the K31 with cast bullets. The main matches at the Cast Bullet Association military matches are shot at 100 and 200 yards. The Springfield pattern 03’s and 03-A3’s and the K31 are the most used rifles. The matches are shot with the reduced 600 yard military target at 100 (mr 31) and 200 (mr 52) yards. 20 shots at each yardage and scores in the 390 plus are shot with both rifles usually with scopes 6x max power. Recoil is a lot less with them lead bullets. Hope this is not too far off topic.

What boolit and load do you use? thanks!

 

[amymorgan20]

I'm loading Hornady 178gr BTHP for my K31 with very excellent results