ed
I am sorry to to say this but the 37x190 is an very early big bore from ww 1, sure it is a rare collector item today.
you must go with current calibers for the 1 bore. the smallest one can be the 30x173 oerlikon with 43,6mm on the base. than the 35x228 oerlikon having 55,1mm and the 40mm bofors 55,8 for the L60 and 57,9 for the L70 with 61,8 and 65mm for the rim. the bofors have a lot of brass on head and �rim to reduce if nessesary. all cases are available with brass cases and the bofors may be the best because it is a rimmed case. If I understand you in right way you looking for a cartridge with a 2 bore and 1 bore bullet diameter and you are not to try copy the old british 2 bore cartridge?

ed

you are very close with the 2 bore and the 1 bore. after british gun barrel proof act fro 1868 a 2 bore have 1,325" bore dia. and a 1 bore have 1,699" bore dia..
there are allways strange things with old guns, the 4 bore barrel in the CIP list is more a old 6 bore with .919".
I think now its possible to make this 4,5" long 2 bore brass from 20mm Vulcan. I say it again the 25mm case is allways steel and the 37mm japanese , 60years out of production, will be rare. it was allways a rare cartridge when it live as a heavy aircraft mashine gun if you compare it with other big bores. better idea is the 37x94R POM POM case, allways to find as collector stuff here in europe. I think bigskysurplus.com have 30mm barrels, this can work for the 2bore.

OldSarge, I'd ask why more people don't. It's a Masterpiece, who care what the chambering is. Some folks climb mountains...

Karl-The plan is to build shoulder fired guns, and you are
right that a few cases will do, and if our developing cases
from other brass doesn't work
out, then machined cases may be an option. Problem is that a dozen 4 bores still will
cost 4-500 bucks to get built and along with barrels and some type of action, which isn't in common supply or even developed to get a hold of, bullets and casting equipment, dies, presses, etc, there will be a lot of money
spent, so if we can figure a way to save on brass it will help a little.And in this process it is still best to make the cases first, of a proper design, and if it works out, and we develope a good supply of cases, then guys will be inclined to get things rounded up to get
guns built.Ed.

Ed, for the real heavies the 1 and 2 bore, unless the minimum order Rocky mountain ctdge requires is high, $40-80 might be okay.

It won't be like buying a normal bigbore where you want 'at least 100 cases' to start with to do load development, grouping, having 50 loaded for an upcoming hunt etc.

The 2 and 1 bore will fire punt gun payloads at BB gun pressures, from firearms 30lbs minimum.
I reckon a dozen cases will last an owner more times than he will fire these things while he owns them.

Of course if we are building actual mounted punt/rampart guns well... the skies the limit and we can burn brass with no limits.


Karl.

ed
that steel cases don't need resizing with blackpowder pressure load is clear but any forming of necks is a problem. some years ago I have reload 8x57IS steel cases only because they say it was not possible. get a nice crimp on this case but the big bores have thicker material on the mouth that the 8mm on the base. the good think is that you can easy made a rim on a rimless steel case when you welding a steel disc on the base. have made cases for the 34mm swiss signal flare pistol from 23mm russian in this way. very fine case for your plan if you can get 34mm brass from switzerland but its allmost rare now.
I say that the measurment's of the old 2 bore in the double gun journal articel will give the only "official" 2 bore case. any other case is a "2 bore wildcat".
the 25" long 30mm barrel for 190$ from bigskysurplus seems me an intersting point for a 2 bore rifle. of course this need a heeled, outside lubricated bullet. 20mm vulcan brass is now on the way, some weeks and I know if the make the 4,5" 2 bore.

Ed,
what kinda pressures are you lookking at running?

I'd be tempted to lathe turn from some 1020 or such (low carbon means it won't harden) 1.5 or 2" bar....

that stuff aint hard to turn, and under flood coolant, is pretty damn friendly.. and even the softest is harder than brass can get (and not be britle)

in THEROY you could tig tubing (techinly pipe after 1.5") closed and coldform.....

*I* wouldn't, but since tig makes it one piece, a U fill weld would probably get you there

jeffe

Any of these cartridges I make will be very close to right size and not on the small side. That is why the 20mm Vulcan won't work for 2 bore. It makes my 4 bore ok. The size of
the two bore in the Journal is close to COTW(1.325)
If we make 2 bore from some steel case it will be close in size so that a minimum of lathe and forming will get it
to fit the 1.325-1.330 size.We might be able to ream out
one of those 25 mm barrels to get a smooth bore or ream
and rifle them. New tooling will have to be made.Ed.

pwm-I tried making 2 bore from 20mm vulcan and it isn't
big enough.Yes I know Big Sky and have some stuff coming from them.Some of these surplus companies sell barrel
or barrel sections and steel cases to
make little cannons, and they say the steel cases spring back with light loads and don't need resizing. We will ckeck on that as a possibility.Ed.

Yes, I have a fella that can make some steel cases
for 1 bore, but it is time consuming.And if we go with steel we can get them from surplus.I did find a picture and dimensions of the exact perfect brass case to build a 1 bore from. It is the Vickers 37 x 190 mm COW 1.5 pdr, brass
case.About half hour in my case spinner-lathe, an expander
and swage, and you'd have a 1 bore case.Anthony Williams has it on his cartridge site, so there may be some around. If anyone knows of any or a source please let us know.. Ed