Swiss Ruben K-31 7.5mm

[MechAg94]

I would still get some of the GP-11 to try. It is very accurate ammo.

I have bought the Privi ammo for ~$12 to $13 per box. Wolf Gold makes some also. I still have not really sat down and tried to group that ammo to see how well it shoots compared to GP-11. The only time I did, the groups opened up a bit.

 

[Slamfire]

I have owned four swiss K31 rifles. Early on I also found that the OAL given in the published reloading manuals was way too long. I have experimented with various lengths and came to the conclusion that as long as the ammunition fed through the magazine box everything was OK.

I was able to get some Swiss ball and test the stuff for velocity comparison. I wanted to develop loads close to factory velocities. I also found that factory INDEP was too slow and inaccurate for any use other than using the empty case and unfired primer as a starting basis for load development. In my rifles I found that 51 grains of 4350 was a close duplicate of Swiss ball and shot well in the K31. The absolute best powder in this cartridge has been the WC852 I purchased from Jeff Bartlett http://www.gibrass.com/. His lot is a slow lot of WC852, and it works great in the 7.5 Swiss with a 168 or a GI 174 FMJBT.

Back in the bad old days, you bought loaded Norma ammo, at astronomical prices, or you used 284 brass. The most expensive 284 brass was less than Norma ammo, so I tried those cases. I found that my 284 cases took about 2 less grains of powder to develop the same velocity I got in 7.5 Swiss cases. That tells me you cannot use data developed with 7.5 Swiss cases, you have to test your own. Also, the rim on the 284 is shorter and did not positively engage the extractor on my rifle. The case would come out of the chamber, but lacking extractor tension on the rim, the cases fell off the bolt face, and dropped into the magazine well.

I have data below with WC852 in 7.5 cases and 284 cases.

Last year I was sighting in one Swiss K31 at 200 yards, using the standard 200 yard NRA bull, and with 174's and WC852 all shots were in the ten ring, and a couple in the X ring. That is just fine accuracy with any service rifle.

24 Mar 04 T = 70 ° F

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


170 grain FMJBT Indep Factory
1 Dec 01 T = 52 ° F
Ave Vel = 2155
Std Dev = 47
ES = 132
Low = 2104
High = 2236
N=10

168 gr Nosler Match 51.0 gr AA4350 Indep brass and primer OAL 2.850

Ave Vel = 2536
Std Dev = 16
ES 45
Low 2510
High 2555
N= 9



174 FMJBT 57.0 gr WC852 Indep brass and primer OAL 2.900"

Ave Vel = 2502
Std Dev = 13
ES 36
Low 2478
High 2514
N= 5

174 gr FMJBT 55.0 gr WC852, .284 Win Brass, Fed210S,
26 May 97 T = 75F
Ave Vel = 2531
Std Dev = 20
ES = 49
Low = 2500
High = 2549
N = 5

 

[cracked butt]

In my rifles I found that 51 grains of 4350 was a close duplicate of Swiss ball and shot well in the K31.

Good info, I'll have to give 4350 a try. I've just been using 41gr of 4064, it shoots very well, but I haven't chronographed it yet.

 

[sixgunner455]

I love my K31. It is my favorite full power rifle, bar none. GP11 ammo is a bit expensive, but I'm buying as much as I can, and hoarding it. When I want a nice, relaxing day with satisfying targets, I break out 20 rounds of it and go punch bullseyes. The rifle and ammo are just that good.

I paid 89 dollars for mine 3 years ago. It is worth much, much more.

 

[ScratchnDent]

Wolf's 7.5x55 ammo is just re-branded Prvi Partizan.

I have had good results with Reloader 15 and 168 gr Sierras.

The last K31 I saw in my loal shop wa tagged at $300! At least it was walnut.

 

[ROMAK IV]

I wonder if he got the rifle. I didn't get to ask pertinant question, as it may have been possible the rifle wasn't a K-31, but a K-11. A K-11 is often worth about $400.

 

[PTK]

K-11 is often worth about $400.

Good to know. I picked one up for $35, but the stock had been cut back.

 

[CHEVELLE427]

284 brass for reloading

I have been using 284 win brass for my K11, (284 ARE ALSO GETTING HARD TO FIND) but not as hard as 7.5 swiss
SEEMS TO BE WORKING OUT FINE.

also been use 30-06 casing for my 8x57 mauser. reneck and trim to size.