Reload for Swiss K-31?

[Sleeping Dog]

Does anyone reload for the Swiss K-31 rifle? I think it's a 7.5x55 cartridge, but haven't seen any 7.5mm bullets. Or, do people just use a 7.62 and hope it squeezes through the pipe?

Is brass available?

Thanks

 

[ocabj]

The 7.5x55 Swiss cartridge uses .308 bullets. The bullet ogive on the GP11 ammo is shorter than standard .308 bullets, though. So depending on the bullet you use, you may have to seat the bullet deeper than manuals list the COL to be.

So far I've tried 165gr Sierra GameKing (Soft Point) and 168gr Sierra MatchKing BHTP in my K-31. I didn't get a chance to work up a real load for the 168s. I mostly tried those because I had a few leftover from an old opened 100 box (after I switched to 175s in my .308). The 165gr GameKings shot pretty well using 44.5gr IMR4064, iirc (in my rifle at least). No chrono data. I've been working on my .260 project as of late, so I have been neglecting load development for my K-31.

The only cartridges I loaded for my K-31 used Winchester branded .284 Winchester brass that I necked up myself. I did buy a 100 pack of the Graf's 7.5x55 brass and full length resized them, but never got around to loading with those yet.

I used data from here:
http://www.swissrifles.com/sr/pierre/data.html

I also found and saved this screenshot of the Sierra computer reloading package:

Again, note the COL listed for the 168gr MKs as 3.060". I can't remember the exact COL I had to seat to, but it was definitely less than 3.000" for the 168gr SMK.

You will want to work up carefully, as always.

 

[Valkman]

You can get brass HERE. $40/100. Ouch.

Oops, that's 6.5x55. Sorry!

 

[ocabj]

I don't see 7.5x55 Swiss brass at brassmanbrass.com.

Either way, you can get Graf's 7.5x55 brass:
GRU75X55 GRAF BRASS 7.5x55 SWISS UNPRIMED PER 100 $27.99 ($23.99 with dealer discount)

 

[Dave R]

I just did my 2nd batch for my K-31.

I use Winchester .284 Win brass, run once through the 7.5 Swiss resizing/decapping die. I did split 2 out of 50 necks doing that. So I annealed another 50 brass, and only split one of those...

I use regular Speer .308 bullets. I tried a lite load using 130gr. Speer bullets and 29 gr. of 4198. Worked quite well.

Also tried a hunting load with 150gr. Speer SP bullets and IMR 4064 powder, as in the screen shot above.

Seemed to shoot them all well.

 

[klw]

Swiss reloads

I like SAECO 0.311 diameter bullets. Would be nice if their noses were a bit more pointed but, well... Powered by 8 grains of Unique they work pretty well.

Of course the 7.5x55 can not be used in the earlier 1889. Reloads, however, can be interchanged between the 1889's 7.5x53.5 and the later 7.5x55 since the difference between the cases is microscopic and with a low powder charge pressures are an issue.

Brass isn't cheap. You can probably expect to get about 15 reloads per cartridge case.

 

[c_yeager]

Oops, that's 6.5x55. Sorry!

Hey thats not a bad price for Norma 6.5 brass.

Here is the place to get 7.5swiss brass

http://www.grafs.com/

I can't hardly ever get their site to work correctly, you may be better off calling them.

 

[Sleeping Dog]

Thanks to all for the good info on this cartridge. Now I have no excuse, I'll have to make room in the safe for one of these Swiss guns.

Regards.

 

[Dave R]

FYI, I shot the 2nd batch at the range today, 100 yds and 200 yds.

Several groups went under 4" at 200 yards, with the iron sights, using the Speer 150gr. soft point and 4064 powder. I'm a happy camper.

(Gotta use a big bullseye to see it at 200 yards.)

 

[Sam Adams]

The Sierra manual lists the OAL at 3.060" because they tested using 3 Model 1911 S-R rifles. The chamber was larger. On the K-31, most of the shooters are loading to 2.90", but the chamber is just a bit different on each rifle, depending on how much it has been used/abused over the years (we ARE talking about a 50+ year-old rifle that saw active duty service, not the latest NIB Remington 700). One guide to use is the length of the Swiss GP-11 ammo (which I believe is 2.90"), but keep in mind that it uses a 174 grain bullet.

One article that is of enormous help in case prep for the 7.5 is found at http://www.swissrifles.com/ammo/reload1.htm It is written by Pierre St. Marie, who is perhaps "the" expert in reloading the 7.5. Here is the relevant portion:

Projectile seating: It is not at all necessary to crimp for the 7.5 Swiss rifles. Crimping introduces a variable that you don't need. The grip of the case mouth on the bullet will not be identical every single time, thus, the unwanted variable.

To determine proper seat depth for any given projectile, keep in mind that the measurement is only valid when the contact of the bullet's ogive and the lands/grooves is determined. Your manual says OAL is 3.020?... maybe for THAT bullet that THEY used, but ONLY for that bullet profile, not all others. Projectile profiles vary from mfg to mfg. So how do you do it?

There are any number of ways, but I've always used the same methodology. Take a sized, empty and UNprimed case, start a bullet into the case mouth leaving it protruding further than is apparently correct. Place it in the rifle's chamber by hand, ease the bolt into full battery and "smartly" eject it. Meassure that OAL and seat it 2 to 4 thousandths deeper. This is a good start. Later, when you've become more deeply involved in data gathering, you may want to play with seat depths to find the sweet spot for your cartridge. I have specifics I use regularly. Yes, there are other ways. If you like your way better .......use it.

Once you determine your OAL for THAT bullet, screw your seating die down until the mouth of an empty case stops the descent and back it out a full turn. Lock the die in place and back out the seater. Now insert case with a bullet into the shellholder and run it all the way up. Turn the seater down till it touches the tip of the projectile. Keep running it up, turning the seater down and measuring until you've reached your previously recorded OAL for that bullet. Do it a few times to assure that it's consistent. Once you're satisfied, lock it in place.

 

[lonniemike]

Reloading for Swiss

That is a lot good info but for one exception I have. Don't use the OAL of GP-11 for a guide for cartridge length. GP-11 is typically 3.043 to 3.060 in the wax ringed/stab crimped ammo I've seen, although I have not seen/measured the newest production without the wax ring and higher ring crimp. I do think somewhere around 2.9" is where most OAL's are going to be at. YMMV

 

[Jim K]

IIRC, Hormady is now making 7.5x55 Swiss, and there is excellent ammo coming from Portugal and Switzerland itself. Loading is easy and much the same as any other cartridge of the type (8mm Mauser, .30-'06, etc.).

One small point, the K-31 does not handle gas well, so make sure your primers seat properly and are appropriate to the caliber. While the caliber can be loaded for the K-31 to near .30-'06 levels, I would not go into the high ranges. The loads posted earlier look good.

For the old 1889 and 1911 rifles, I would load well down, into the .30-40 Krag range.

Jim

 

[S_O_Laban]

Jim do you have a source on the Portugal ammo? I was aware of the Swiss but not the other.

 

[pbhome71]

The Portugal ammo is FMN. I bought 200 rounds from Cole a 2 years ago. I believed that it was $7.50/box of 20. I heard a rumor that it was a special run at FNM.

-Pat

 

[Sam Adams]

lonniemike

That is a lot good info but for one exception I have. Don't use the OAL of GP-11 for a guide for cartridge length. GP-11 is typically 3.043 to 3.060 in the wax ringed/stab crimped ammo I've seen, although I have not seen/measured the newest production without the wax ring and higher ring crimp. I do think somewhere around 2.9" is where most OAL's are going to be at.

This is a bit curious. Isn't the GP-11 what the Swiss issued to their soldiers, specifically for the K-31? If so, and if the OAL is something like 0.15" longer than the 2.90" that most reloaders use, wouldn't the rifles have a problem either chambering the GP-11, or with accuracy and/or overpressure?

 

[ocabj]

This is a bit curious. Isn't the GP-11 what the Swiss issued to their soldiers, specifically for the K-31? If so, and if the OAL is something like 0.15" longer than the 2.90" that most reloaders use, wouldn't the rifles have a problem either chambering the GP-11, or with accuracy and/or overpressure?

Not necessarily. Overall length isn't a good indicator of a bullet's distance to the lands since all bullets have a different taper / ogive. It's possible that the GP11 bullet's ogive is lower than the average modern day .308 bullet. Thus the GP11 bullet is seated higher than you would seat a modern .308 bullet such to get it to chamber properly.

 

[Dave R]

I can vouch for the need to check OAL carefully.

I tried seating a Speer 150gr. FMJ (NATO equiv.) to the cannelure, then chambering in my K-31. It chambered, but I had a hard time extracting it. And when I did, I had an empty brass! The bullet stayed in the throat! It was jammed in the lands pretty good.

So I will ignore cannelures and test for OAL and contact with the lands with ALL K-31 loads.

 

[lonniemike]

Reloading for Swiss

Yes down load 89type and unconverted 96(rare) actions to lower 30/40 vels. But GP-11 was designed and made for the 'old' 1911 series actions and the Swiss arsenal upgrades/conversions such as 96/11 and others. GP-11 is no longer issued as 31 or 57 rifle ammo as they have gone to .22 cal rifles but I believe they still have some use for it in machine guns. GP-11's approx 46K CUP pressure is real close to 30'06's approx 48K CUP pressure design. Most projectiles will have to be seated much shorter than GP-11. The pricey Berger VLD bullets will seat out further to mil length as its nose profile is quite close to the Swiss's. Best-o-Luck

 

[Sleeping Dog]

I looked at a GP-11 bullet next to a Sierra 168 gr HPBT. The GP-11 is almost a straight taper from the tip to the sealant, sort of a skinny bullet for most of its length. The Sierra is "thick" almost to the point, almost a "round-nose" by comparison. It looks like the Sierra will have to be seated with a shorter OAL in order to have the same gap to the lands.

(Got the gun, now waiting for the brass & dies)

Regards.