British .303 Converted To .410

[Good Cheer]

Does anyone know, are the British .303's that were converted to .410 just a straight tube inside, as in no forcing cone?
Is there anything there that can be rifled to shoot cast boolits?

[Outpost75]

I would think that the existing bore diameter could be left as-is and the tube rifled to a .429-430 groove diameter with 20-inch twist and you could make a .43x2-1/4", simply necking up .303 British brass, as they did in India and Pakistan and use .444 Marlin dies with a .303 British shell holder. Anybody who is set up to rebore and re-rifle to .44 Magnum should be able to do this. It should be a real easy job because all you would be doing is rifling the existing tube. No chamber work should be necessary except to throat for your chosen bullet. You could use .444 Marlin data as a guide, but I'd stick to the starting and mid-level loads and limit myself to about 25,000 psi.

The .410 Mk1 Ball cartridge is NOT a 2-1/2" .410, but is assembled using an un-necked .303 British case, charged with smokeless and wadded, loaded with a .390" round ball. Cartridges I have are 2-1/4" long and are shorter than a .410!

Attachment 129346

[JeffinNZ]

It's been done. The .444 is pretty much just that.

[historicfirearms]

I had one of these for a while. A normal 410 shell would not chamber. I made some brass from 303 brit, annealing first and fire forming. Rifling the existing barrel sounds like a fun experiment.

[leadhead]

I have one of these that has been bored for 3" 410's. I've been thinking of using
41 cal cast bullets loaded in 303 cases. The bore measures .410 just thinking
about it for now. What do you guys think of the idea?
Denny

[Stoats]

Rifling it would be mad, but whatever.

Easier, if you really must insist on harming a historic piece, is to run a modern .410 shotgun reamer into the chamber and shoot slugs.

[Outpost75]

.410 slugs are pretty pathetic.

You can approximate the .410 Mk1 Ball cartridge using 18 grains of #2400, card wad over the powder, two 1/4" felt wads, then fill the case to the mouth with granulated polyethylene buffer, thumb in a cast .390" round ball. Crimp the ball in the end of the shell by bumping the case mouth against the shoulder of a .308 Win. seater die while adjusting the seating stem to the mid-point of the shoulder, to position the ball in the case mouth while the case is crimped over it.

Much easier to load than slugs and more effective too.

[pacomdiver]

outpost,
thanks for the data, gotta load some to finally try out my pair of 410 muskets

[groovy mike]

A bunch were imported and reamed out to standard American 410 dimensions decades ago, but a new batch is coming in lately that have not been rebored. You can simply blow out 303 british brass and reload load with 410 componants. Or buy teh milsurp Indian 410 ammo made for them by the case at Dan's ammo.

[Ballistics in Scotland]

There are two kinds of rifle of this description. As has been said, those produced in India used a special .303-based case. They were intended for riot control, for if you see the ringleaders who are cheering you on shot with Lee-Enfields, you are unlikely to give much thought to the possibility that it is only tweezer work. I doubt if any were made as .410s from scratch, for in two post-war periods there were more .303 rifles than they knew what to do with.

But some rifles were converted as standard .410s in the UK, and although they were left with the magazine, buyers were told that they would only function as a single shot. They might bear the name of Elderkin, a gunmaker in Spalding, Lincolnshire. Since they still had rifle sights and were the clumsiest .410s on the market, I would suspect that a lot of people intended to use them with slugs. I doubt if either variety were choked. and neither has to be Ishapore made.

If you ever want to try your hand at rifling a barrel, in a jurisdiction where it is legal, this would be a pretty good way to start. Even if you foul up, you are only left looking for a rifle barrel for a firearm that started its life as a rifle. I think it would also be an easy relining job with the liner Track of the Wolf sell for the .30 Luger, though you would probably need the chamber reamer to restore the front end.

[andrew375]

For a time many firearms here were converted to smoothbore, not for use a shotgun but due to the victim disarmament legislation of the time making it easier to legally own a firearm that met the criterea of being a shotgun than to legally own a firearm that didn't. As a result an awful lot of fine firearms were vandalised by being smootbored, usually without rechambering, I once saw a 105 Howitzer smoothbored for this reason. The other thing is that, at the time, there was little interest in military rifles like SMLEs, Mausers and P14s so the only way for the trade to shift them was to convert to .410 to be sold as a cheap knock around. They were never meant to be repeaters.

Personally I wouldn't bother getting it rifled. Instead I would get it re-barreled and restored to it's original condition, apart from anything else it will be worth a lot more money

[Ballistics in Scotland]

I don't doubt that many historically interesting rifles were treated this way in the UK. I also saw a dealer offering a deactivated .442 Webley RIC revolver, which after hard fought-for concessions were made, became a freely ownable antique if made up to 1939. That wasn't a change in the law, either. It was in guidance to the police acknowledging that it always had been. It is to be hoped that they have an exceptionally hot corner of hell waiting for the person who desecrated that Webley.

But the 105mm. howitzer must have been smoothbored for some other reason. The shotgun certificate (which they must issue unless they find some convincing reason not to) has always applied only up to 2in. bore. I think you could own it freely as an antique if it was pre-1939, since black market 105mm. ammunition must be hard to find, but not a later one. Howitzer crime seems unlikely to be affected.

[cpileri]

sir,
where are you seeing new imports? I've been looking for one.
thx, C-

but a new batch is coming in lately that have not been rebored. .

[texaswoodworker]

Personally I wouldn't bother getting it rifled. Instead I would get it re-barreled and restored to it's original condition, apart from anything else it will be worth a lot more money

Honestly on this side of the pond, it might be worth more as a .410 or as the wildcat mentioned. A typical .303 British Lee Enfield doesn't go for that much. I bought one that is in pretty good condition and that ended up having quite a bit of history to it for $300 a few months ago. Most I've seen go for between $300-$450.

[Good Cheer]

Anybody know what cast boolit cartridges these could be rebored to?
.444?
.45 Colt?
.44 Special?
.455 Webley?
Others?