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Bore diameter of GSP .32? Bullet suggestions?
Posted: Tue Oct 30, 2007 2:18 pm
by Jauncey
What is the bore diameter (preferably in decimal inches) of a Walther GSP Expert in .32 S&WL? I'm in the process of buying bullets for mine, and I'm wondering whether I should go with the .312, .313, or .314 options.
What bullet(s) would you suggest for the pistol? What weight? I intend to use the standard 1.5-1.6 gr or Bullseye or WST for a starting load. I have some Trail Boss to perhaps try later. Although I don't currently have any, I am considering checking out VV310, as well.
Thanks!
Posted: Tue Oct 30, 2007 9:15 pm
by 6string
Every gun is different, even of the same make and model. Therefore, you should begin by slugging your bore. You'll need a soft lead round ball a few thousands/inch over typical bore diameter. I'd suggest .318-.322". Just tap it down the bore with a mallet and wooden dowel (1/4" probably best). Measure the slug at the widest point. That is your groove diameter. You should select a bullet of the same diameter or .001" over. Another consideration is chamber tightness. If it is tight, don't use the oversize bullet or you may run into feeding jams.
Hope this helps!
Posted: Fri Nov 02, 2007 6:47 pm
by Raymac
I think the reply by 6string is correct for the normal flat-base bullet or a cast bullet, however I think the most successfull bullet in the Walther GSP has been the Lapua hollow-based wadcutter. I know it was developed specifically for the GSP pistol. It is .314" diameter......and I think you will find that the bullet actually rides on the top of the lands. When fired the thin walls of the hollow base expand into the grooves creating a very good gas seal with a minimum of drag. The fact that the bullet rides on the top of the lands also means that there is a very low coeficient of friction and a resulting better accuracy. The hollow base gives a better flying characteristics with the heavy front and lighter rear end. I think that you will be hard pressed to find a bullet that beats the Lapua HBWC in terms of pure accuracy at 25m.
At one time I imported and sold a bullet swaging press made in the UK that produced a HBWC bullet in .314" diameter.....it was very successfull and the weight could be varied easily. Interestingly, the Lapua bullet has longditudinal grooves in front part of the bullet. Good luck.