Unique Falling Block Muzzleloader

[relayer1989]

This past weekend I picked up a unique 45 Cal muzzleloader from the Belleville Gun Show.

It appears to be an Investarms Hawken barrel and stock fitted to a Hopkins & Allen falling block shotgun.

Is this build something that was done? Or is this a one off?

A custom breech plug was made to use with 209 primers.

One issue is that the breech plug is completely open, which means the powder would lead right up to the primer. It also means you have to load with a spent primer in place otherwise powder would spill out, and then swap to live primer before firing. Thinking I might try to create a new breech plug with a proper flash hole.

 

[Potashminer]

You might want to check out a few factory made in-lines, if you are considering to make another breech plug. I used to own a Thompson Center Omega in-line in 50 calibre - as I recall, the breech plug accepted 209 primers, but had a tiny - perhaps smaller than millimeter - flash hole to it - I do not remember any concern about loose powder falling out through that flash hole. So far as I remember, those breech plugs were sold as individual units for replacements - I think I had at least two of them, when I had that rifle - they threaded into the rear end of the barrel - I would unscrew them and remove to be able to scrub that bore "straight through" The rifle had an external hammer. I seem to recall a warning about NOT enlarging that hole when cleaning it. The rifle was rated for Magnum loadings, so I presume that system was decently skookum.

 

[RRCo.]

It's a one-off and would probably be best hung over your mantelpiece. Those actions are cast malleable iron and hollow cast at that. Some of the late ones may have been steel, but malleable iron is sometimes called "semi-steel" and who really knows what they used.

And what you have there is not one of the shotguns, but one of the rifle actions with the tang sight holes on the tang. The largest calibre they were made for was .38SW if I remember correctly.

 

[Licensed to kill]

I see it is .45 cal barrel. I fail to see the point of making it into a pseudo muzzleloader but if you could chamber it to .45 long colt, that would be something cool, fun and useful.

 

[mooncoon]

It's a one-off and would probably be best hung over your mantelpiece. Those actions are cast malleable iron and hollow cast at that. Some of the late ones may have been steel, but malleable iron is sometimes called "semi-steel" and who really knows what they used..

I don't see a problem with the action;if the breach plug is screwed into the barrel, then more or less, the barrel is the only part that takes the strain of shooting. I think that if you made a breach plug which screwed into the barrel and had a .070 hole or less to the powder, you should not have too much problem with blow back. The breach block should divert most of the gasses coming back but that is something you need to find out by firing from a bench with a piece of paper held a couple of inches behind the breach

cheers mooncoon

 

[RRCo.]

I see it is .45 cal barrel. I fail to see the point of making it into a pseudo muzzleloader but if you could chamber it to .45 long colt, that would be something cool, fun and useful.

I don't see the point either. .22LR is what the action was really built for and what most of them were. .32RF was an option and .38SW centerfire was the max but that's it. That one has the short receiver, the 922 series were longer. They were all takedowns IIRC and the barrels were a push in fit locked by a single screw from below or from the right side on the early ones like this is. Being an early one it is sure to be malleable cast iron.

You're probably right Mooncoon, but personally I'd prefer a conventional muzzle loader with a percussion cap and a hammer. The firing pin is only held in with a little cross-pin.

 

[saskbooknut]

I don't see a problem with the action;if the breach plug is screwed into the barrel, then more or less, the barrel is the only part that takes the strain of shooting. I think that if you made a breach plug which screwed into the barrel and had a .070 hole or less to the powder, you should not have too much problem with blow back. The breach block should divert most of the gasses coming back but that is something you need to find out by firing from a bench with a piece of paper held a couple of inches behind the breach

cheers mooncoon

Mooncoon has it figured out.
The action was originally a shotgun action. It was not a rimfire boy's rifle.
As a muzzleloader with a threaded breech plug, the action is not bearing significant breech thrust.
With competent workmanship, it should be as safe to fire as many inline muzzleloaders.

 

[RRCo.]

I see you are correct saskbooknut: there were some 20g shotguns made with an enlarged version of the same slab-sided action as the rifles, and from the wide breech aperture this must be one of them. At least some of the 12g versions with the stepped receiver sides didn't have full depth shoulders behind the breechblocks like the 20g seem to have had.

 

[saskbooknut]

Looking at Frank de Haas "Single Shot Rifles and Actions" this appears to be the medium size H & A action, which he says was originally made with cartridges as large as .38/55.
You are correct that the 12 and 16 gauge shotgun action had a wider breech with reinforced shoulder panels.

 

[brybenn]

I have adaptors for 12ga break action guns to con ERT to inline muzzleloader and powder does fall thru. I load and travel with and spent primers. When I reach my hunting area I swap them for live primers. Haven't had an issue