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Double Rifles, Single Shots & Combinations >> Paradox and Bore Guns
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beleg2
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Reged: 15/08/07
Posts: 591
Loc: Bahía Blanca - Argentina
Rifling the choke?
      #145343 - 08/11/09 12:53 AM

I just bought an spanish double to shot round balls.
Right barrel is cilinder but left is full choked.
I have some .715" RB that rolls through RB nicelly but you have to hammer them throug left barrel.
I thought about removing LB choke but what about making some primitive tools and rifling it?

Martin

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DarylS
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Reged: 10/08/05
Posts: 26612
Loc: Beautiful British Columbia, Ca...
Re: Rifling the choke? [Re: beleg2]
      #145363 - 08/11/09 06:07 AM

I had that same idea many years ago, Martin- I wanted to rifle the chokes of a .410 double - though it would be a 'cool' gun for BP loads and a 300gr. slug.

I don't see any reason why not, although I'm not sure what you mean about 'primitive' on the toooling. Use of another barrel (any descent calibre ML barrel should work) as a guide. Cast a lead lapp inside the 'guide' barrel around a mandrel for guiding the rifling head inside the shotgun bore. European barrels usually have a longer "End Choke" than US made barrels,s so the resulting rifled choke should be longer, which is good - maybe 4" to 5" tops - perhaps. thus, the guide barrel could easily be as short as 10" or longer, of course, would be better. Lead lapps on both, one a guide and the other holding the cutter would be the way I'd do it. Lots of measuring to get things lined up for pouring the lapps, of course. use almsot pure lead for the 'guide' and harder lead for the cutting tool's lapp, I'd think. Kind of thinking things out of course, while typing this. Hope the typing's not too bad.

Most older full choke 12's run around .690" in the bore and and .729" to .730" in the main barrel. .040" (40 thou) was the 'normal' full choke, called "40 points of choke".

This will give .020" or so per side of rifling depth to your 'paradox'. The ball used should fit the major bore diameter to within a thou or so, just as a Paradox bullet fits - much larger than the .715" mould you have. When the balls hit the rifled section, they need to engrave enough to take the twist. If you use a cupped wad to hold the ball in the centre, it's possible the wad might transform the twist rate to the ball, but I certainly wouldn't guarantee that. Full length rifled or smooth works fine with cup-wads and RB's, but the cupped wad & ball might merely strip when it hits the short rifled section at velocity.

As for rifling twist, about anything from 56" or slower to perhaps 100" should be fine, I'm sure. Oh course, it would probably have to be faster for slugs in smaller gauges.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

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beleg2
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Reged: 15/08/07
Posts: 591
Loc: Bahía Blanca - Argentina
Re: Rifling the choke? [Re: DarylS]
      #145474 - 09/11/09 01:32 PM

Thanks Daryl,
My idea was to use a pistol ML barrel as guide or to make a short with a square steel rod twisted.
Most of the barrels I have are 1-30 to 1-48".
I have measure the barrel:
OD: .829"
ID: .694"
Wall: .0673"

If I rifled as you said .02" grooves the wall will be .0475"
If I rifled to a groove diameter of .715" it will have a .057" wall.
Is it enough to stand the pressure?

The other option is to cut 2.5" off the barrels and get a 25" cilinder ball and shot gun.

I will have some time to think as I will get guns papers in three weeks.

Thanks
Martin

Edited by beleg2 (09/11/09 01:36 PM)

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beleg2
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Posts: 591
Loc: Bahía Blanca - Argentina
Re: Rifling the choke? [Re: beleg2]
      #146342 - 22/11/09 12:21 AM

Hi,
Im having problems with login. Im not loged at main index but Im loged into the diferent subforums.
So I can post only in those forums the you can see unloged.

I finally decide no to get the choke rifled as this will be a legal problem here.
I will leave the barrels smooth and uncut as the choked barrel is backbored.
It have a long choke (6cm)and I plan to ream it to cilinder for RB.

Thanks
Martin

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DarylS
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Reged: 10/08/05
Posts: 26612
Loc: Beautiful British Columbia, Ca...
Re: Rifling the choke? [Re: beleg2]
      #146352 - 22/11/09 04:38 AM

I'd cut it off myself for 25" Cylinder tubes, but that is legal here.

My 12 bored double smoothbore managed 8" groups at 100 meters, firing 2 lefts and 2 rights, with both black powder and with smokeless powder.

The walls seemed a bit thin to me for the amount of 'work' required of them.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

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beleg2
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Reged: 15/08/07
Posts: 591
Loc: Bahía Blanca - Argentina
Re: Rifling the choke? [Re: DarylS]
      #146397 - 23/11/09 01:07 AM


I will be very happy if I can shot 8" group at 100 meters.

Here in Argentina we have to register al gun (but muzzleloaders).
In shotgun you have to register barrel lenght because we have diferent categiries according to its lenght.
+60cm civil use.(also .22LR rifles and revolvers up to .38 Spl.
38 to 60 cm condicional civil use (de same as high powder rifles and pistols).
less than 38 cm only law effocement and military use.

To cut my barrels more than a couple of cms I have to ask permition.
That means time+$$$$ if the RENAR ever let me cut it.

To get to cilinder part of the barrel I have to cut more than 3".
I do not know what to do yet.
Probably cut a little after reboring the choke to cilinder.

Thansk
Martin

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DarylS
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Reged: 10/08/05
Posts: 26612
Loc: Beautiful British Columbia, Ca...
Re: Rifling the choke? [Re: beleg2]
      #146407 - 23/11/09 02:55 AM

Here's a thought - cut off the "end choke". That is the barrel at the muzzle that is cylinderical in shape and usually the same length as a shot column. If you cut off the end choke, you will be left only with the tapered section of the choke which is more easily removed, either with a reamer (expensive) or with a brake cylinder hone spun in an electric drill. The hone I used was the one with flat stones, not the little abrasive balls. I have used the brake cylinder hone system on 3 shotguns, which worked perfectly when 'adjusting' chokes and load developmet. It will take some time to get all the choke out, but it's possible. When the stones wear out, merely glue on 60 to 80 grit emery cloth.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

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beleg2
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Reged: 15/08/07
Posts: 591
Loc: Bahía Blanca - Argentina
Re: Rifling the choke? [Re: DarylS]
      #146412 - 23/11/09 03:15 AM


Thanks Daryl.!!!!
You always have good and pracitcal ideas.

Martin

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