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
Is brass available?
Thanks
Oops, that's 6.5x55. Sorry!
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.
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.
Sam Adams said: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?