Making Rifled Shotgun Cases

[303Guy]

I have this rather ambitious idea to make a set of rifled cases for my 410 shotgun.
The idea is make them from brass using the button rifling method. The body and head would be made separately and screwed together - the button needs to be pushed back out.

What I'm thinking is to bore the case body first, rifle it then turn down the outside.

[Cap'n Morgan]

Interesting! But why not make them as a single piece - if the button can be pushed in, it can also be pulled out. You'll need a hollow-based slug for the rifling to grip the slug - unless you plan on imprint the rifling into the slug by force. I'm not sure if accuracy will be any better than from a smooth bore, but it's always fun to engage in new firearm projects.

[303Guy]

Hi Cap'n
The button would be short with no pulling means. Perhaps I can change that.
I was thinking of a wadded and ribbed slug to go through the choke. The idea of a hollow base may well be a better option. Cutting off the choke may be another option but that may reduce the effective range of shot - which may not be an issue anyway.

Another thought is to patch the slug to make it compressible enough to pass through the choke. Also a thought is to use a round ball in a cupped wad to keep it clear of the bore. Only the wad would engage the rifling unless I make the case ID smaller and rely on the wad expanding to seal the bore. Several ideas to consider.

Addendum;
Using a loading press would make rifling with a push-pull button feasible.

[BigEyeBob]

I have a 410 slug mould made by CBE here in oz , its adjustable so you can make what ever wieght slug you want . Its made to cast the hollow base slug so the slug fits inside the wad ,I havent tried it as yet ,so cant really say how
effective it is ,but the fellow I got the mould from reckons it worked a treat. Cant extract any more info from him though ,sadly the poor bugger passed away about 6 mths ago.

[Oklahoma Rebel]

have you heard of rifled choke tubes? they do pretty good from what I hear, and you can always put your regular chokes back in later, no damage!

[longbow]

I'd suggest making a rifled sizer then size the slugs to suit the rifling in the case... so pre-rifled slug as some do with muzzleloaders. otherwise I have to think that the slugs will wear the cartridges very fast.

I'm with Oklahoma Rebel, I'd go with a rifled choke tube or if you don't want to modify the gun, use Brenneke style slugs with ribs that will compress in a choke. I've made a straight ribbed push push out mould that makes a ribbed slug. They are quite easy to make:

- bore a piece or round bar to the size you want (bore diameter in this case); I bore right through now and make an end plate to hole the HB pin/ejector
- turn a piece of round bar to fit the mould cavity
- use a slitting saw in lathe or milling machine to put 3 to 4 slots in the end as deep as you want ribs for bearing surface
- drill then bore the middle out of the bar to the bottom of the slots leaving 6 to 6 ribs
- drill the mould for a set screw or two to hole this slotted core
- turn a piece of steel round bar as a nose form (I like TC shapes) larger than the cavity then turn the nose form you like (I like TC shapes) and drill through then turn so that the TC nose meets the top surface with sharp edge (like the nose of a nose pour cavity
- bore the cavity to slide fit the nose form in so it is flush with the top
- make an ejector pin and HB or flat plug with pin depending on if you want HB slug or attached wad slug

You now have the majority of your mould make. You still need a sprue plate and handle.

This is a nose pour mould with separate nose form. I use a magnet set into a piece of dowel to handle the nose form when casting.

Drop the nose form in, close the sprue plate, pour, cut the sprue, invert the mould, push the ejector pin and the slug and nose form drop out, pick up the nose form with the magnet and drop it back i the cavity, repeat. no harder than using the Lyman style HB or HP pins and moulds. Mine all work quite well.

You already make push out moulds so this is nothing new for you, just a little different. You can make the mould to suit your bore and weight preference. Hot melt glue works well for attached wad slugs but of course has to be kept from the bore by use of a shotcup or paper patching which you also do for .303 so again, nothing new. Pretty easy and it does work.

I've got pics of my moulds and can take some more but the PC melted down a while ago so got rebuilt (second time in a year thans to Windows 10 then a virus) and I haven't get the pics reloaded yet. There may be some still pics of moulds and/or on this site in old posts if you search. Yes, a picture is worth a thousand words but you got the thousand words here... sorry!

Longbow

[M-Tecs]

For doing a couple of brass cases the old time wooden rifling machines would be the easiest. The question I have is what will the rifled case accomplish? In a smooth bore the bore friction will slow or stop the rotation of the slug.

[longbow]

Indeed it will unless the slug is a loose slide fit but even then I think doubtful any useful rotation will last because there will be some bore contact and the pressure of the wad on the base. There is not a lot of rotational inertia in a slug or boolit.

[longbow]

If 303Guy is bent on doing this, and nothing wrong with trying, a simple rifling machine can be made by twisting a bar of 1/2" key steel to the appropriate pitch (1 turn in "X" inches) then cast a hard lead "bearing" around it. That's how I made my rifling machine for my rifled choke tube. So far I have just rifled a piece of 3/4" pipe to test it but it worked well. I used a piece of file as a cutter and a paper shim set up.

Once made the rifling machine can be used to rifle brass or steel cartridges per his plan or to rifle a choke tube or short barrel. Mine will only do about 6" long tube but good enough for a rifled choke tube. And to head off questions like "Why do you want to make a rifled choke tube when they are readily available?" I want a deep groove slow twist choke tube which is not available.

We each have our quirks! So good luck to 303Guy in his quest and I hope he successful. Trying and proving others wrong is how we make progress.

Longbow

[Geezer in NH]

I would turn a 41 mag barrel to fit a sleeve before screwing with rifling a an adaptor. I have access to rifling machines for "government work" but that would waste the resource.