Why not larger caliber rimfire cartridges?

It may be because the pressures of a larger caliber would mean that stronger, thus thicker, brass would need to be used throughout. This means that the firing pin would have to strike the rim that much harder. I would assume that such a weapon would be difficult to operate, and may be unreliable.

Modern centerfire cartridges use fairly thick brass around the bottom of the case, with the relatively weak primer in the middle.

Just my thoughts, I could be totally off base.
- The Next Generation

there is/was the http://en.wikipedia.org/wiki/.44_Henry

There were rimfire cartridges all the way up to 50 caliber.

They all fell out of favor because of the reliability and performance advantages their successors enjoyed

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There were scores of them in the late 19th century, but the transition to smokeless powder and the higher pressures associated rendered the design obsolete except in very small cartridges.

There has long been a small group of older folks who would love to see a new larger caliber rimfire for small game hunting, like the old .25 Stevens or .32 Long rimfire make a comeback.

But, the fact of the matter is, Speed Sells.
Witness the .22 WMR, and .17 Hummers.

If you came on the market with a .25 rimfire small game load that shot a 70 grain SWC bullet at 1,400?
It would knock a rabbit or squrrels socks off DRT as far as you could hit them, without destroying the meat.

But it would be a dead cartridge a few years after introduction, because the round failed on the market.

Because it didn't reach 2,000 FPS, or some other magic velocity number, and the internet experts all said it would be useless.
Because you couldn't shoot crows and gophers with it at 250 - 300 yards. Plus, it would be completely worthless for SD, because it was a rimfire.
And it was also way too big too big for mice in the castle larder!

rc

There were rimfire cartridges all the way up to 50 caliber.

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There was, for one brief, shining moment, the .58 US Musket cartridge, used in the first breechloader conversions of the Springfield Rifle Musket.

There has long been a small group of older folks who would love to see a new larger caliber rimfire for small game hunting, like the old .25 Stevens or .32 Long rimfire make a comeback.

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The problem there is cost. I'd buy a rifle in 32 Long rimfire, if ammunition cost was say, twice that of .22 LR. But not at ten times the cost per round.

Cost is the big issue. Brass centerfire cartridges are reloadable, rimfire cartridges are not. If they made steelcase rimfire, and could cope with the pressure, maybe, but at present it's too expensive to sell making brass disposable cases that big.

The Next Generation nailed it - If you made the brass to withstand the pressures of modern cartridges you could not disrupt the rim of the case enough to have reliable ignition.

Another issue: With larger calibers, you'll need more priming compound distributed around the rim. Priming compounds are part of the health issues we face with shooting, and are obviously pretty sensitive in the manufacturing processes. Keeping the amount used to a minimum is a good idea.

Well i am actually longing for proper .22 centerfires, something along the lines of a .22LRC (LRC=Long Rifle Centerfire).

Perhaps a family of .22 with the same bullet size but different case lengths, preferably rimmed straight walled cases.

Well i am actually longing for proper .22 centerfires

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The .25 acp isn't far off.

I wonder if .22 lr is cheap more due to tremendous economies of scale more so than any intrinsic characteristics of rimfire cartridges.

Other rimfire cartridges such as .22 magnum, 5mm magnum, and .17 hmr approach the price of cheap 9mm ammo, so a spicy rimfire probably wouldn't be cost effective.

Well i am actually longing for proper .22 centerfires, something along the lines of a .22LRC (LRC=Long Rifle Centerfire).

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John M Browning invented it, he called it ".25acp"

Or 22 Hornet, for that matter.

kozak6 said:

The .25 acp isn't far off.

I wonder if .22 lr is cheap more due to tremendous economies of scale more so than any intrinsic characteristics of rimfire cartridges.

Other rimfire cartridges such as .22 magnum, 5mm magnum, and .17 hmr approach the price of cheap 9mm ammo, so a spicy rimfire probably wouldn't be cost effective.

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Not even the .25 NAA can come close to matching the .22 LR, now the .32 NAA comes pretty close. But why don`t they make bigger Rim Fire have no idea.

Brass centerfire cartridges are reloadable, rimfire cartridges are not.

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Actually, rimfire ammo can be reloaded. It isn't easy and it is dangerous. But it can be done.

I was reading about rimfires last night and was surprised to learn that 22lr has a higher pressure rating than some common centerfire handgun rounds such as .380 and 45 ACP

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Vaarok got it right.
It is simply not cost effective to produce larger rimfire cases at the present costs of raw materials.

Well i am actually longing for proper .22 centerfires, something along the lines of a .22LRC (LRC=Long Rifle Centerfire).


Kind of the flip side of the OP, smaller centerfires.
There are, or have been, such things.
Old, the .22 Maynard Extra Long.
New, the .22 CCM (Cooper Centerfire Magnum.)

A step larger and easier to implement would be a .22 WCF which is the parent case of the .22 Hornet except loaded with black powder and a .228" lead bullet.

I'd love to be able to do some shooting with my .41 Swiss!

FWIW, reloading .25 ACP is a pain. Just handling those itty-bitty cases over and over can be a problem. The semi-rim doesn't inspire confidence in the shell holder's ability. The small powder charge makes even small variations significant, percentage-wise.

Double post. Sorry.

Enlarging rimfires also runs into a strength of materials problem. The larger the chamber (and hence the cartridge), the thicker the material needed to contain the same pressures.

To illustrate, assuming a .22LR cartridge develops, say, 20,000 psi, the thin brass can hold that in a "vessel" the size of a 22 LR case.

But put that same pressure in something the size of a .380 cartridge with the same wall thickness and it will rupture. The tensile strength required to hold it dictates a much thicker vessel wall.

Force = pressure times area.

Since the outward pressure is vectored into stretching (tensioning) the case wall, it can be seen that the tensile forces on the wall are sort of multiplied by the internal area, that is to say, the diameter of the case. The bigger the case, the greater the area the pressure has to work on. In turn, then, this results in greater tensile forces on the cartridge case wall.

A simple analogy:

It's like blowing up a party balloon. You've surely noticed how hard it is to expand it at first, but as its volume (and therefore its internal area) increases, it gets easier, at least until it's ready to pop.

While it is true that the chamber supports the cartridge, in any firearm, there are inevitably areas of the case that are unsupported. So scale that same principle down to these unsupported areas, and you have the same tensile strength problems, albeit on a smaller area..

Imagine a rimfire 5" artillery shell. It could not be made out of brass the thickness of a .22 case. (Apart from melting and handling problems.) Unless it were absolutely 100% supported in the chamber, it would rupture at any small unsupported area.

I always wondered about the new "Short Magnum" cases, where they retain the same internal powder volume, but with a bigger diameter case to make up for the shortening. The tensile forces on those bigger diameter cases (and therefore the chamber walls) must be enormously increased, compared to a conventional long case of the same volume, where the diameter is smaller.

Terry, 230RN

I'd love to be able to do some shooting with my .41 Swiss!

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It is fairly easy to convert the Swiss Vetterli's to center fire and suitable cases can be made from .348 Winchester brass. The only difficulty is finding proper sized bullets.

It's just plain uneconomical to build cartridges in large calibers in rimfire. Centerfire is cheaper to make and it's so established. Imagine creating a 30 caliber rifle round in rimfire. Nobody's gun would be able to use it, so you'd have to invent an entirely new lineage of firearms, your cartridge likely will not have much following, and it will be expensive. New calibers which have caught on in recent times such as 5.7 and 6.8 have caught on because they were already at least somewhat created for the military and therefore at least had some manufacturing lines and matching guns meant to fire them, not to mention that at least partial adoption meant that they could take the risk of going into the civilian market. The 40 S&W became popular because it was the FBI round with good characteristics and there was a niche for it as a mid power handgun cartridge between 9x19 and 45ACP, boating superior power to the 9mm, better in-flight characteristics than the 45, having high energy, being managable, being friendly for high capacity magazines, and having good terminal performance. Of course, the establishment of production lines for LE and the FBI meant that some of the initial cost of making the gun and the ammo would be offset by government contracts.