multi cartridge 22 cal weapons

[preventec47]

I got this idea when reading about some revolvers that offer
a regular 22 lr cylinder and also a 22 WRM cylinder.

I think the same thing could easily be done with breech plugs
screwed into a single shot barrel type rifle.

Lets say before they drilled the bore and chamber of a barrel
they created a screw in breech plug that had  perfect flush
face with the barrel interior.  Then later just drill the bore
and chamber out with the breech bore screwed into the
barrel for say the 22 WRM.  Then screw out the breech plug
and insert another and drill out the chamber and barrel
part of the breech plug for regular 22LR.

If we could figure out how to switch from centerfire to rimfire
like  one other single fire rifle company ( cant remember which )
we could also extend the options to 22 Hornet, 223 and even
22-250    etc    I would give the barrel a 1 in 8"  twist rate               

This would set a new hi in the history of firearms as far
as versatility for a weapon.

as far as the small groove where the breech plug meets
up with the barrel and concerns about crud buildup etc.
I think all that would need to be done is a slight
taper just like what is done when the chamber throat
leads into the rifling normally.

[IOWA DON]

With the breech plugs I would suggest using the variable rate rifling. I forgot the term for it. However, just ahead of the chamber its twist rate would be very slow, but at the end of the barrel the twist rate would be much faster. I am thinking that Smith & Wesson uses that type rifling on one of their magnum pistol cartridges. Anyway, there would be a long free-bore for the shorter cartridges, so if the rifling was either strait or had a very slow twist on the breech end the bullet could enter the rifled part of the barrel without such an abrupt rotational acceleration. Also, I have a commercially made chamber adaptor so that a .32 ACP pistol cartridge can be fired in a .300 Win Mag barrel. I understand that accuracy using them is OK. However, the adapter is a little too large for the chamer in my .300 Win Mag barrel so I never got it tested out.

[gunnut69]

From what I understand you're describing a rifle with a chamber dedicated just to cartridge adaptors? Why not just buy a barrel in 22Hornet, 222Rem or 223 and cartridge adaptors for it. The barrel should be for the TC Contender or Encore. They use a switch on the hammer nose to allow both rimfire and centerfire from the same hammer. The barrel you describe would be less adaptable as without a chamber adaptor it would be no caliber at all. The TC barrel could be fired with it's normal cartridge and adaptors used for other rounds as needed or wanted.

[S.S.]

that is called "gain twist" rifling..