The Russian Mosin Nagant Forum

Hi Folks,

I keep reading that the bore size in the Gewehr 88 is supposed to be 0.321" bore by 0.311" or so lands, and that the 0.318" bullet was a holdover from the blackpowder days, but that it was found this caused unacceptable gas erosion so they bumped the bullet to 0.323" to fit the bore.

Now, I've been shooting and cleaning, shooting and cleaning.

First time I slugged the bore I got 0.3165". Now I'm getting 0.318".

That's all well and good -- the crud's gone.

But, why are folks saying these are 0.321" by 0.311"? I do have the "S" conversion.

I'm sort of confused. Any help would be appreciated.

Thanks,

Josh

Josh in the olden days they just couldn't hold that bore size worth a dam, so you will find them to vary quite a lot. This is a common problem with a lot of Military Rifles in general, so everyone says slug that bore and see what you have. If she slugs .318 then I'd go that diameter. But and there are always buts in reloading this bore discrepancy between the older Mausers in 8X57 and the newer rifles such the 98 Mamusers in the same caliber is why U.S. manufactured 8X57 is loaded as light as it is. They all worry about someone sticking that .323 bullet into a .318 bore and blowing themselves up (can you say law suit). Another thing to think about is that you can shoot an over bore size bullet in the rifle, Hornady doesn't make many .311 diameter bullets most of their stuff is .312 but I shoot these in my Mosins and my Enfields you just have to shoot a light load so you don't over pressure things. So in theory you could push a .323 bullet down that barrel but I'd stay away from that sort of thing until you know more about what you are doing.
Now if you decide to shoot cast bullets I'd go .001 to .002 over bore diameter to insure a good seal and shoot a hard cast bullet and depending on load you might consider using a gas check.

I am by no means an expert but I would think you would do well with cast bullets. There is a website called "Cast Boolits" that is wealth of info http://castboolits.gunloads.com/ Good Luck