I have a rough bore 9x57 half round/oct with a rib.

What cal can I rebore to? Muzzle diam is .585

.585-.355 = .230

Rich

I don't see any options richj. That small muzzle diameter is a bummer.

How does it shoot with the rough bore???

Also what if you polished out the barrel real good, removing as much roughness as you an and then shoot .358 cup and core type bullets in it???

Saeeds bullet diameter tests seem to oindicate that there is very little increase in pressure with bullets a few thou oversize. Just start with low pressure loads and work up.

You might not want to shoot Partitions, AFrames and X .358 bullerts in it but Sierras, Speers, and Hornady cup and core should be OK.

You do not need premium bullets in a 9x57 anyway...

Rich,

How about 9.3x57? You'd be going from .356" to .366".

George

You could get one of the Tubb barrel lapping kits.

Also before you do anything you might want to get some of that spray Moly bullet coating, and try it.
It just might Reduce fouling enough so you could hunt with it like it is...

Good ideas.

I have lyman 9x57 dies and a 358 taper expander.
I've been using 8x57 brass necked up.
I need to try a few more loads/bullet in 358.

George, wondering if 9.3 would cleanup the bore.

Those diameters that George gave were groove. Bore is the tops of the lands or reamed hole diameter before rifling. I'd say that the bore would be cleaned up. 9.3x57 is a pretty good cartridge.

Fire Lap the sheit out of it. I had a 1903 Springfield with a nasty bore and did that till it shined. Then it was a .3115/06 so there was no factory ammo, but would shoot .312 174 gr Hornadys into 1.5 moa with only a 4X scope.

A "soft" cup and core .358 bullet would probably bump up and give you acceptable hunting accuracy.
(Woodleigh makes some great ones)
We tend to forget that any rifle that will shoot 3 in 3 inches at 100, will kill any game you'ld be after with a 9x57.
There is also the option of a custom mold with a 275 gr gas check bullet at 1800-1900 fps which is about as fast as the 9x57 can push a jacketed one of the same weight.
Sounds like a fun project to bring a classic back to life with a minimal outlay.
May we see some photos ? Thanks.

Wow.
Nice!

That rifle is exquisite!

More photo's please.

I would shoot it more with .358" bullets.

Have you tried the 180 Speer or the 180 gr Horn. SS pistol bullets?

Clean the bore again with both brushes and bore cleaning compounds.

If it still does not shoot well then have the crown recut.

If the outside of the rifle looks that good, then I am guessing the barrel damage is from shooting corrosive ammo and not cleaning it properly over the years.

Again, just how bad does it shoot with standard ammo?

9.5x57, or .375 rimless, 9.5x56 MS....whatever you want to call it.

After you fire lap it, let us know how it shoots.

If you want, I'll give you $600 for it as it sits today because I know it can be salvaged.

y0u can have the bbl for 600

You know if I had a Mauser that was in need of a barrel that would not be a terrible deal. Even a rebore would only make it an $850.00 barrel and considering the profile, rib etc. you could not get that done today for that price.

Yet another (expensive) option would be a total relining where the old barrel is step bored out to very thin and a new liner fitted. It would make a great 257 Bob or 6.5x57.

It is a beautiful classic rifle. I wish you the best of luck in getting it back in the field.

AS my step-son would say "sweet"

Normally I'd opt for a 9,3mm bore in either 93x57 or 62. But, since that may bee too small an increase, the 9.5x57 would be real fun or the 10.75x68.