I have a sporter weight rifle in this caliber with a very strong action. At the muzzle, a slug mikes .316. Is it feasible to rechamber to 8x57R and load .318 bullets? I'll make a chamber cast to measure bore diameter at the breech.

I would say that if the neck of the new chamber is too narrow to allow a .318" bullet to slide easily into the mouth of a fired case, then buy a resizing die and take your .318" bullets down to whatever groove diameter the barrel proves to have. If the .318" bullet does slide easily into a fired case, then it should be OK to use as is. .002" difference is bullet diameter makes no difference, it the cartridge case will release the bullet when fired. I have found that resizing jacketed bullets up to .003" per stage is entirely feasible, and has allowed me to reduce jacketed bullets up to .009" in three steps.

Xausa, Thanks for good advice. A chamber cast shows bore diameter ahead of the chamber to be .317-.318, so there's a bit of choke to the bore. I have some old Norma bullets in .318, 196 grs. Hawk offers a range of weights. I have 20 Norma cases now and they seem to be available on the market.

rocky mtn bill,
You are certainly entitled to do what ever you want with your own property, but since you asked for our advice, here is mine. I have a couple rifles that were "born" 8.15x46R and are now chambered for something else( one also lined). I have another that had original markings ground off so original caliber is unknown, but was re-bored and re-chambered( both operations oversize so intended caliber cases split over 50% of the time). Since they had all been "messed up" , I got them cheap because the owners didn't want to see them any more. xausa is correct about the bullet in the neck test. I usually limited re-sizing jacketed bullets to .005" once, so I appreciate the 3 x .003" hint. I often see rifles with even a tighter barrel than yours ( down to .3125") and still intended to use the "standard" bullet. The 8.15 bullets were usually shown as .324" but the main body was .318" with the extra diameter a "stop ring" which allowed loading at the range by seating the bullets by hand without sizing and still seating all bullets to the same depth. My advice is to shoot the rifle "as is" using cases made from 30-30 cases, sized, trimmed, adjust rim diameter and thickness; with bullets in accordance with xausa's advice. You didn't say what type rifle you have, but if it is one of the "tip up" single shots with a single locking lug, they were never offered in 8x57 IR. They were intended for lower pressure cartridges up to 9.3x72R. If you are "bound and determined" to re-chamber it, you would be limited to 8x57R/360 or 8x58R S&S( the S&S may not cleanup the old chamber). In the end, you wouldn't gain much, donor brass will be more difficult, bullets would be the same , you would have to find or make a reamer, and everybody would fuss about messing up the rifle ( it's yours but they will still fuss). You asked, so there it is. If you decide to do it anyway, I will take it off your hands cheap, when you get sick of it.
Mike

I would guess that old barrels that could have steel intended for lead bullets might not hold up well on a diet of jacketed. How old is this rifle? What is the action system? Sounds like you want to make it a high power hunting rifle.

The action is the one FDH calls a Kettner. The rifle is nitro proofed. It was made in 1938. Although it is chambered as it is, it is hunting rifle weight and style, not a target rifle. Half, Yes, I want to have a rifle I can shoot big game with. I have no interest in a 32-40 type cartridge. Der Ami, I'm not sure what you mean by not gaining much; it's the difference between a 32-40 and a 30-06.

My Original Haenel 98 was in 8.15x46R
I fitted a 22-250 then 6mmRem barrels to it
I did have to change the bolt out for the .473 brass base.
Easier to get a surplus bolt and be able to convert the
gun back to original if I wanted

Mike

Also regard the rate of twist.
8,15x46R should be 1 turn in 360 mm.
Most of the 8 mm cartridges (.318 and .323) had 1 turn in 240 mm.

fuhrmann

fuhrmann, good point. This barrel's rifling makes a turn in 14". Thanks.