K31 Reloading

[Latigo]

#30412 is the VLD comparable to the GP11 bullet

Latigo

[MAUSER88]

I was going to use either Varget or IMR4895.

[Uncle Ray]

Has anyone developed/worked up a load with lead bullets.

I am a cast bullet freak and have shot cast from almost eveything I own, but never in the K31.

Any thoughts??

I'll stick my neck out and give you a good load that I use in my Swiss Martini Schuetzen and my Model 1889, both with 3 groove rifling, however I'm yet to try this load in my K.31 as one of the problems that come to mind is the tight throat in the K.31, which may mean that the bullet has to be seated too far into the case, even when seating the projectile against the lands.
I suggest you set up a dummy cartridge with a slightly loose neck so that when loaded into the chamber, the rifling seats the bullet into the case. If the base of the bullet goes below the base of the shoulder I would reject that bullet design. Alternatively you could try a mold that casts the front part of the bullet UNDER .300".
My best loads comprise either a 170 to 180gn gas-check bullet, cast using Lyman No.2 mix, and lubed with 60% Vaseline & 40% pure beeswax, with the bullet base sized to .308"; and with 34gns of 3031. I use this same powder load for all bullet weights.

I prefer Remington 9 1/2 primers, but I dare say you could get success from any brand. This load will group 5 shots, bench rest, at 100yds, into 1.5". On a still day, with no wind, I can occasionally get five shots into one inch. I have also tried flat-base bullets, (no g/c) which are also accurate. No leading with my loads, either.

Good Luck

[coppertales]

What does your reloading manual show for loading this cartridge? I have had good luck with 4064 powder....chris3

[andiarisaka]

First thing you'll find with cast is that a lot of US bullets don't work too well. The K31 has a very short throat and a very tight bore. mine, for example is .295 bore and .305 groove diameter. You can find a lot of info for reloading cast bullets on castboolits.com. And if you look around in the group buy area, you'll find that they're even selling a mold designed specifically to overcome the obstacles that the K31 presents. Just search for K31 or Swiss, and you'll find a lot of information there. There are a few US made molds that will work well. The RCBS silhouette bullets, the Lee 155gr are a couple that work well.

[Patrick Chadwick]

andiarisaka,

the Swiss 7.5x55 is not a true .300 caliber.

CIP bore diameter = 7.51 mm = 0.296"
CIP groove diameter = 7.74 mm= 0.305"

So your K31 is perfectly OK. Obviously .308 bullets are a bit of a squeeze, but the Dynamite Nobel book says that is not a problem, the original GP11 bullets having a max. diameter of 7.81 mm = 0.3075".

What I think matters is the form of the ogive. I suggest you get hold of a G11 cartridge and measure the bullet as precisely as you can. The max. diameter given above only applies over a very short length. It is a boat-tail bullet with a very long ogive, so that there is almost no cylindrical section, and it is obviously superbly well matched to the throat angle in the G96/G11/K11/K31 family. My G96/11 is the most accurate "off the shelf" rifle with milsurp ammo that I have ever had in my hands, and I think this matching is part of the secret.

I can do no better than recommend that you look for a bullet that matches the ogive of the GP11 bullet as closely as possible.

Patrick