Thread: Cracking the Code on another Double Rifle

This reloading post is about a very different double rifle.
With solutions to problems you don't often come across

I recently got lucky and brought a Husqvarna 17A Combination rifle.
It has the Lefaucheux forward facing forend locking lever




Thanks to a helpful forum member I got this early this week.

But had done a fair bit of research since I brought it and before I got it in hand.
So I had a pretty good idea what it might be and how I might be able to get it shooting

What makes this Double Rifle ? Particularly interesting is that it is 20 gauge rifled in both bores
The Left bore is twist rifled



BUT the Right bore is Straight Rifled

Luckily I know a few people around the world who are similarly affected by the vintage rifle bug and only an email away is a guy who's owned a 20 gauge straight rifled Rolling Block.
So I got a heads up on what I might expect

Turns out that's what I've got

The left bore is 1:60" 8 groove twist rifled with a .662" groove and 46mm long chamber

The right bore is 12 groove straight rifled with .660" groove and 75mm chamber

Kaboom and you get a case out that's front half is blown out to the left chamber



The tape is pretty important because then you have a concentric case and the extractor will catch the rim nicely

This one case was used a number of times in both bores and it slowly fire formed further back but not completely.

Load and fire both barrels twice for a very slow 4 shot group

As you can see from the chamber casts this is a 20 gauge rifle and doesn't have a forcing cone like a shotgun would have.

So despite being 20 gauge the thin brass cases actually take a 16 gauge ball or bullet.

I was unable to find and 20 gauge brass available in NZ
So I committed a crime and decided to use a 577 basic case because it has a bigger rim than Magtech 24 gauge brass

Trim it to 46mm
Anneal it heavily
Put a couple of wraps of tape around the base so the case is centered when the mouth expands during the first firing

70 grains 1 1/2 FG Black Powder
Two hard over powder cards
Force a .650" round ball in with a small Arbour press

Make 4 cases and load them all with the 70 grain BP load



Shoot 4 through the left and 4 through the right.
From a standing rest at 30m
L1 to L4 from the twist rifled barrel is a definite group.
R1 to R4 from the straight rifled barrel are still a group but much much bigger than the Left barrel
But at least the Right barrel shoots to the same place roughly

What is the purpose of the straight rifling?

Originally Posted by Friwi

What is the purpose of the straight rifling?

Strange, I agree, but you can't argue with the results!

Straight rifling has been around for several hundred years in muzzleloaders for a whole range of supposed reasons.

Originally Posted by Friwi

What is the purpose of the straight rifling?

Was designed for buckshot but it will shoot a ball aswell as above

The idea of straight rifling was to keep the spread of buckshot to a minimum as far as I understand
Id say this rife was almost certainly designed to shoot a ball or small slug (if you can call that small lol)
And a buckshot round in the straight barrel
If you miss or wound the animal with the 1st shot
The buckshot round would be a good follow up on a running animal at close range

This is the theory as I understand (could be wrong)

Originally Posted by Friwi

What is the purpose of the straight rifling?

Shot, I think, holds the package together, maybe.
I have one and from memory, I load a .54 brass cartridge with lead projectiles, I’ve also used the same in the straight rifled barrel. The rifled barrel is reasonable accurate.

They should let the air out of something pretty good.

There are reputed to be some Swedish laws about not shooting Moose with shotguns

But really the 75mm chamber is the give away
Straight rifling keeps a buck shot or bird shot column perfectly straight and should group well

So I was able to load a standard 20 gauge plastic case for my buck shot tests
60 grains BP
Two hard cards
15x 30 caliber lead balls
Thin over shot card
Shot through straight rifling



12 or 13 of the 15 were on a 500x500mm sheet of paper at 30m

Next test was
60 grains BP
2 hard cards under shot
7x 34 cal 60 grain balls which were awkward to stack in the case
Over shot card



The 7 pallets are joined by lines and numbered.
There are numbered smaller shot among them
But it's a much tighter group than the small shot.

I've ordered some .315" 47 grain buck shot which should pack in neat 3s in the 20 gauge case and take 4 stacks so 12 balls.
Hopefully it will group better than the small shot and not as tight as the large shot.

The straight rifled barrel was intended as a shot barrel that throws a good pattern despite not having a choke and will shoot a ball or conical Minute or Moose at relatively close range

Originally Posted by akaroa1

I've ordered some .315" 47 grain buck shot which should pack in neat 3s in the 20 gauge case and take 4 stacks so 12 balls.
Hopefully it will group better than the small shot and not as tight as the large shot.

The straight rifled barrel was intended as a shot barrel that throws a good pattern despite not having a choke and will shoot a ball or conical Minute or Moose at relatively close range

I have some 20ga 9 ball buckshot and it's pretty effective on goats at the ~30m range

I had a few weeks to research this rifle before getting my hands on it and found enough info to avoid buying a 20 gauge bullet mould and going down the wrong route

This info on Swedish guns seemed the most authoritative

Double Gun Model 17A Shotgun: 16x65mm / 20x65mm. Shotgun barrel sometimes straight rifled. Rifle:20, 24 or 28gauge Steel 73cm. 1884-1930 Generally no. Some weapons made after 1900 have edge engravings. Walnut. Checkered pistolgrip.Some weapons made before 1900 have english grip. Lafaucheux backaction hammer cape gun. Rifle barrel is "Gauge rifle", loaded with brass shell, blackpowder and round ball."

And this information about the model 17A suggests very few were made with the Gauge twist rifle barrel

"17A
This model was made 1884 to 1930, between 1912-1930 totally 50 was made. Before 1930 this model had no engraving. A m/17 as cape gun with one 16 or 20ga smooth bore barrel, and one 20, 24 or 26ga rifled barrel."

Conflicting information on the time line for border engraving but does place my example as 1 of only 50 and pre 1930

The M 17B with 12.7x44R rifle barrel was made in bigger numbers and the M 17C with 9.3x72R rifle barrel was made in much bigger numbers