Thread: Tight Bore 8x57

Hello - my new to me 8x57 has a bore slugged at .320 It also has a long throat.

The 170SST's I have measure at .322, I have tested loads with them for velocity and pressure and all is normal (haven't had the opportunity to fire them for accuracy yet).

Any experience/thoughts on what projectiles might go best for accuracy - .322 constricting down or .318 obiturating up ??

Give the bore a good going over with a mild metal polish to take it down a little and smooth any high spots?

The original 8x57J had a bore diameter of .318". The later (1905) 8x57JS had a bore diameter of .323". Modern 8x57 is designed for the JS .323" bore and is not considered safe for the 8x57J. If your rifle is fairly old it could be for the older J cartridge. Prior to 1905 the caliber was only marked 8x57, and the J and JS marks were used post 1905. The two barrel diameters persisted well after WW1 in sporting rifles and should be appropriately marked.

Well - the bore is mint, as in like new so I won't be going near it with anything abrasive. The barrel is a commercial german one, 1/2 octagonal to round with an integral rib.

Gundoc I'd be interested what you make of the proofmarks, to me the German ones indicate a .318 bore, the English the .323 (and proofed 1954 ??)

This rifle is proved for the 8x57J (.318" bore) under the German Proof Law of 1892 and before the Proof Law of 1912, and further confirmed by the British proof for the 227 grain bullet which is correct for M88 8x57J cartridge. It is not designed for the modern 8x57JS load.

Thanks for that Gundoc. I'll have to rethink the "project"

Harry Brown the “cast boolit kid” can stage some pills down for you. He did it for a mate.

His contacts are on the beaver grease page.

I'm still committed to getting it going with jacketed bullets, I have .321 Hornady FTX's in 165gn and Norma .318 180gn so will give those a spin. Sounds like it would be sensible to limit pressure to MAX 45,000 to 48,000 psi which will get me to about 2400 fps to 2600 fps - still plenty fast enough to be a very effective hunting rifle

Woodleigh do a .318" projectile. There is a box of them on trademe at the moment.

Lets have a look at the whole rifle that teaser of the barrel has me thinking express leaf sights and ivory forebead prove me wrong.

That's a bummer Tentman. Is .318 sizing gear easy to come by?

Here are a couple of pics . . . (ignore the scope, thats just for testing purposes - it deserves a "classic" scope)





Its a very nice rifle, light, beautifully balanced,and is a delight to carry.

There is no problem with shooting it as an 8x57, it just requires a little commonsense, and to be treated like the old-timer that it is, the proof marks show it was provisionally proofed in Germany in 1926, and reproofed in the UK in 1955. The UK reproof is a "butt covering exercise", they have not said its not safe for 8x57JS, they've only ticked it for the older less intense cartridge. Most of the older 8x57's with less than .323 barrels were re-throated for .323, and while I have no proof, a barrel made in the 1920's would certainly be thus.

This is backed up by the fact that the .323 loads I have tested to date show no signs of pressure (let alone excessive pressures) and velocities are as expected from the extended throat the "converted" chamber has. Having said that it would not be wise to push up to full 8x57 velocities, getting 2800 fps as I'd hoped with 170's won't be happening.

All is not lost though, I have yet to fire test groups but given that this style of chamber is often not favourable to boat-tail projectiles (like the Hornady SST 70) I'll just have to try others. I have some pointed .321 165's, .318 160's and will get some 323 180's and the 200gn Woodleigh's Stug pointed out.

A 165 or 180 at 2600 fps will take any game I'll strike in NZ and if I scope it right, won't be a limitation to shooting out to my self imposed limit on game, which is definitely not more than 400M (and I nearly always pass up shots of more than 300M)