Why no larger rim fire ammunition than .22?

[xbananax]

I was wondering earlier today why ammunition manufacturers haven't started producing rim fire ammunition in sizes larger than .22?

In California at least, you would think there would be a HUGE market for this, as it would allow people to have more "evil features" on rifles before they're considered AW's.

Is this a cost issue? I would assume rim fire ammunition would be cheaper to produce over centerfire.

Seriously, what gives

[FatKatMatt]

Rimfire casings aren't as strong as centerfire casings are; there was a thread from a while back about high pressure rimfire though.

[subdjoe]

But they COULD bring back some of the blackpowder classics - .44 rimfire, .54 rimfire. Of course, then Spencer and Henry would need to tool up to start producing the lever guns in those again.

[DedEye]

It would be nice if they'd bring back the .32 rimfire, since there are still some nice, shootable rifles around in that caliber.

[ZapThyCat]

Isn't 7.62x54r Rimfire?

[ETD1010]

Isn't 7.62x54r Rimfire?

nope. It uses a large rifle primer.

[PJA]

The "r" stands for rimmed.
Pete

[ghettoshecky]

Isn't 7.62x54r Rimfire?

that would awesome if it was, I would so get a pimped out Dragunov

[Alan Block]

I have a Remmington in .41 rim fire.

[bohoki]

I have a Remmington in .41 rim fire.

what a derringer?

[BillCA]

As noted, the rimfire case as we know it won't hold up to higher pressures. Add to that, the rimfire case is notably less reliable than a centerfire primed round and there is a limit to the heat it generates to ignite the powder.

A rimfire case starts off as a closed-end tube and the closed end is swaged into the rimmed shape. This leaves an opening around the rim for the primer material. The rim, is thus hollow and because it has to connect to the main casing, where it is folded over forms a weak-area of the brass. Early .45 Colt brass, called "balloon head" brass, was made in a similar fashion and noted for its frequent failures around the rim and case-head when loaded "hot".

The case is primed by inserting a drop of a fast-drying liquid primer mix while the case is spinning. Centrifigual force slings the mix outward, into the cavity formed by the rim. Several things can go wrong here. A thin mix leaves little primer mix on the base and more in the rim, resulting in weak ignition, hangfires or misfires. If the mix is too thick, it may not disburse into the rim evenly, leaving gaps that can cause misfires or duds. Likewise, too thick of a mix can cake and crumble due to vibration, causing misfires or duds.

When fired, pressure builds in the case and attempts to push the case-head backwards. If the case head was unsupported with a stout charge, the pressure would try to "straighten out" the rim of the case. Think of the toe of a sock that's folded into a .22 case head shape. Pressure from your foot straightens it out. But metal fatigues when bent and reversing such a fold will rupture the case. The concern over ruptured case heads is one reason .22 revolvers use countersunk charge holes for the ammo.

There's a limit to the thickness of the rim and the metal that can be used and still provide reliable ignition. You could make the walls thicker, but that poses a problem of sufficient striking force to "pinch" the rim edges together to ignite the primer mix.

Certain powders, such as extruded bar and ball powders (296, 696, etc.) are hard to ignite and require a "magnum" primer. Such a hot primer mix in a rimfire case would risk rupturing the weak areas around the rim.

Unless and until the cartridge manufacturers find a way to resolve some of these problems (especially the pressure issues) you won't see any higher-powered rimfire cartridges.

[AJAX22]

My first pistol was a .32 rimfire "Young American Bulldog" I've still got it.

bullets are about 2$ each

Its really reliable and quite safe.