I'd considered a 30/40 krag conversion years ago . At the time .303 sporting ammo was difficult to find locally and all the available surplus ammo was old and gave many misfires. No. 4 rifles were selling for as little as 12 bucks in good condition, but even the store that sold them didn't carry .303 ammo.
They were selling NIB No 5 Jungle Carbine for 35 bucks, again the only reason I didn't get one was the difficulty in finding ammo. I called every sporting goods store around and nobody had any. I have no idea why, but I do remember that a court case was in the news in which a hunter had been killed when his Enfield blew out at the breech. Probably local stores were leery of the .303 at the time due to product liability.
A few years later I came into possession of a Krag Carbine. The bore was in the worst condition I've ever seen. I couldn't get a bore brush through without stripping off the bristles. Externally and mechanical the gun looked fine.
I couldn't find any gunsmith willing to make a new barrel at any price. Partly because the barrels had left handed threads I'm told. Also Krags had gotten a bad rep because of its single lug design.
I'd given the idea of converting the Krag to .303 some thought then, because good .303 ammo was becoming available and I'd tested the feed using an old .303 round I'd had laying around.
Now days a gun like that can be sleeved to return it to safe operating condition. Wish I'd known that at the time. Though the gun I traded it for was a nice one and probably close to the same collector value.
The guy I traded it to was a Krag collector and had no intention of firing it, otherwise I wouldn't have even considered trading or selling a gun with such a dangerously corroded bore.
From the looks of it, the gun had been used extensively with Cupronickel jacketed ammo and never properly cleaned.
Cupronickel locks in corrosive primer salts which eat away the bore silently over the years. You could see strips of the old jacket material peeling loose from the rotten bore surfaces. I have no doubt that the gun would have blown up if testfired, probably even if all that crap could have been removed.
Rebarreling a number four to 30/40 to make good use of the many .308 bullet types out there is an interesting idea, but good .311-.312 bullets are becoming more available as the resurgence of interest in this round, and of cartridges with similar bore sizes like the 7.62X54 , 7.62X39 ,and 7.65X53, continues to grow.
PS
I do have an otherwise nice No.1 Action that had been rebarreled many times at the Lithgow arsenal according to a friend who knows how to interpret the stampings at the rear of the receiver. When I tried to rebarrel this gun using a new replacement barrel we found that the front of the receiver had been crushed down by the repeated rebarrlings and it could no longer accept a standard barrel.
Since a custom made barrel is in order I figured on having one made in 6.5X57R. The OAL of the 6.5 rimmed is a hair longer than the Magazine will accept but since this would be mostly a handloading proposition I could always seat the bullets to suit the magazine length.
Another cartridge I've considered is the 7mmX30 Waters. Might even go for the good old American 30/30 round for that matter. The action length could be well used in coming up with good loads that couldn't be used in the Leveractions these two last cartridges were designed for.
I'm looking to make a lightweight sporter firing a cartridge suitable for whitetail and usable for a variety of smaller game using handloads taylored for the particular game, Turkey, Groundhog, Squirrels (using cat sneeze loads), etc.
I had begun trying to fit an old two groove No.4 barrel by setting it back a half a thread then rechambering, but I've found that the thread diameters, though similar , are not the same. No.4 threads are a few thousandths smaller in diameter. I might still use this barrel by boring it out to .410 and make the gun into a takedown rifle with both rifle and shotgun barrels.
