doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Odd pinfire double rifle

Here is an odd one for you all:
My RFD (read FFL) inspection was due and the officer who came to do it is an old friend and very much interested in oddities. He brought with him a set of barrels discovered in an old barn when it was being cleared out after many decades of having 'stuff' thrown in to a heap in the corner.
These barrels turned out to be from a pinfire double rifle, heavily etched twist tubes and ribs, cross bolt or wedge forend fastener, unrecognised bolting, no proof marks of any kind, no makers marks of any kind, in fact no text or cyphers of any kind at all.
However the really odd bit which I hope one of you can explain is that the rifling, which is a bright and unmarked as a new pin, is normal in the right tube but STRAIGHT in the left! No twist at all. Same number of lands, same bore, same profile but no twist whatsoever.
Any ideas?
Sorry about the rubbish pix but you may just be able to make out the rifling.

Early, Early, still experimenting with twists it appears to me.
Must have taken it off when the straight rifling didnt work

Likely one barrel mainly for ball/bullet, the other for shot. At least all the straight "rifling" I've seen was for shot dispersal.

But I don't discard the possibility that this was an early experiment in stabilizing balls AND dispersing shot.

A serious, if perhaps ignorant, question: can you call straight grooves "rifling" at all? Seems to me that the definition of rifling is SPIRAL grooves.....

Toby,

I once had a 24 gauge Husqvarna hammer double with spiral rifling in one barrel, straight rifling in the other. It was a 1880's vintage gun with Le Faucheux underlever. I never fired it, and I'm not sure what it was intended for.

Shallow rifling has been used in shot bbls for the purpose of spinning the charge for greater dispersal. Straight grooves have likewise been used in an attempt to insure against any spin in attempts to increase the pattern. Quite often though these have been put in only at the muzzle.
Rifled choke has of course been used for a ball/shot gun, but generally the spin induced to the shot charge is said to produce more open paterns than the same choke would without the rifling. Never owned one so can only state what I have read on them.

i cant argue about the effect on shot, but as far as early and experimental, the straight Vs spiral rifling experiments began with muzzleloaders in the early 16th and possibily the late 15th centuries. the effects where well known but a mathamatician in the early 18th century scientificaly explained the concept. Even gain twist experiments predates pin fire.

so after a couple hundred years of playing around, I would bet this builder knew exactly the result he wanted, it is just that we don't. Dont forget these would predate any cup wads for shot shells so if it is for shot, unless it were wrapped somehow the affect would be limited.

it would be interesting to breach the barrels some how to send some loads (shot and ball) down it to see how they react.