.22 Auto Rimfire

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klyph

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I had an idea for a new rimfire cartridge based on the ever popular .22 long rifle. The purpose of the cartridge is to make a round as inexpensive as .22lr, but with an auto loader profile. I've been told that the reason they don't make double stacked high capacity magazines for .22lr is that the rim is too wide in relation to the overall length. My solution was to swage out the diameter of a .22lr case to match it's rim, obviously leaving a portion of the case immediately above the rim for the extractor. This cartridge would not utilize a heeled bullet, as it would need to headspace on the case neck like a traditional auto cartridge. The caliber would remain the same as .22lr. The resulting dimensions would allow reliable feeding in high capacity magazine designs including coffin and p90 style magazines. The manufacturing cost should be inline with that of .22lr, although the production volume would also impact the retail price.
Another advantage would be that firearms chambered for .22lr could easily be rechambered for .22ar by reaming out the diameter of the chamber. I imagine most .22lr magazines might have enough extra room to accommodate the new dimensions, though this is not the purpose of this round, just a side benefit of using the most popular cartridge in the world as a parent. The real purpose would be the ability to design new high capacity plinkers and compact deep concealment firearms with decent capacity. Imagine a full size handgun that holds 30 rounds, a subcompact that holds 15, and a 100 round coffin mag for your AR style carbine that is the same length as the 25 rounder you currently use.
I don't care about making money on this idea, I just wish major manufacturers would jump on it and run with it. What do you guys think? Thoughts? Critiques? Suggestions?
 
Well...all I know is I tried a .22 BCG with .22LR in my 6920, and it gunked it up so badly, I made a mental note to just buy a decent .22 rifle with a large magazine. Maybe a ruger 10-22 or similar. I was so miffed I nixed the idea of buying one of the kits, which costs nearly as much as a separate .22.

Perhaps if someone gave me a .22BCG kit, I'd use it for my wife, and make her clean up the Colt before I went back to 5.56 goodness.

Other points of your post, I have no insight, perhaps others will. I don't know. It seems the rush for larger capacity magazines would harbor a weight penalty for some? Maybe not?

I hate having to pull-up my pants constantly, because I'm carrying a lead brick around, scarily close to my ass or privates.
 
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klyph said:
My solution was to swage out the diameter of a .22lr case to match it's rim, obviously leaving a portion of the case immediately above the rim for the extractor.
Click to expand...
How do you foresee igniting the priming compound currently contained in the rim?

What would the striker crush the rim against if you eliminate it's ability to seat against the back of the barrel?
 
It's a rimfire cartridge. It won't work in a double stack magazine. It is what it is. Its usefullness is in no way diminished by the lack of a double stack magazine.:scrutiny: If you really need a double stack buy a Glock like everyone else.
 
My assumption was that the primer would ignite regardless, given the hammer usually overlaps where the sidewall supports the rim. Maybe I'm wrong, but I have no way to test my theory.
 
As 9mm said, I don't see how you could ignite the powder charge. If the firing pin hit the case it might punch a hole in the case.
 
klyph said:
My assumption was that the primer would ignite regardless, given the hammer usually overlaps where the sidewall supports the rim. Maybe I'm wrong, but I have no way to test my theory.
Click to expand...
Your basic assumption was flawed.

The .22lr case is an example of the old balloon head design...think .44Spl or .45 Colt from the cowboy era. The rim isn't solid, it is hollow and priming compound is spun into it while wet. This compound is ignited when the striker crushes the two sides of the rim together against the rear of the barrel. That the striker may also impact where the sidewall joins the rim is incidental.

You don't have to test it, just look up the construction of rimfire cartridge cases
 
fir_m05_t07.png

Even without the rim being supported by the breech face, I believe there is a way to manufacture this in such a way that it will function reliably. Perhaps the friction additives to the priming compound, or merely manufacturing the cases so that the sidewall is slightly thicker at the base, offering enough support to ignite the priming compound.

These are good criticisms, keep em coming.
 
I have 15 rounders for my 1911 conversion kit, and 25 rounders for my M-4 upper. Honestly, I don't feel a crushing need for improvements.
Click to expand...

My experience has been the opposite. I often hear complaints of plinkers wanting to shoot more and stop to reload less. Also the standard of 10 rounds for full size .22 pistols is annoying when a similarly proportioned 9mm holds 50% more.
 
Any suggestions on a way to test my theory? I thought of finding a .22lr that would fire out battery, but the case would have no support whatsoever, not to mention the danger of firing a gun out of battery. Hmmmm.
 
They already have one available. It is called .25 ACP and it is not all that inexpensive. It would be easy to make a higher cap MAG for these but nobody wants one I would guess. If they made a carbine for 25 ACP would you buy it? A .22 round would have the .25 base as that's what you need for a centerfire primer. You could neck down a .25 round to use a .22 bullet with the same ballistics/pressure. Think FN 5.7. The reason that .22 is so cheap is the primer built into the rim means less machining of the brass and the relatively inexpensive rimfire firing mechanism. I am really amazed that a .22 LR round cost so little considering what goes into it.
 
Just beacause they may fire out of battery doesn't mean they reliably will. It may be possible to redesign for a sturdier front of the rim. But for me, cost is a big factor and 14 rounds in a Marlin 60 is fine.
 
Frog, as you point out the whole point is to make a rimfire with an auto profile due to the fact that primers cost more than a round of .22lr
 
You seem to forget that you won't start with the economy of numbers when you introduce a new round. Part of the reason for the low cost of .22 rimfire is that they are selling 3 billion+ rounds a year.

I wouldn't surprise me if a new .22 auto cartridge was more expensive than .25ACP rounds to start...at least $14/50rds (based on the .17 RF). It isn't like you'll be able to use it in any existing .22lr firearm...you'd either have to rebarrel or change the location of the striker in the breachface
 
This subject comes up every couple of years or so. Use your Google-Fu, Kemosabe!

It's going to be more expensive than .22 RF to produce, no way around it with the more complex case. It's only advantage would be that it would be easier to make higher capacity magazines.

There are plenty of people out there who would buy it for that reason alone.
 
Are you talking about an auto loader profile with an extraction groove?

With a strengthened extractor system - over most current designs - you might be able to fire such a cartridge using the extractor as the anvil to the hammer of the firing pin.

Even forgoing inconsistent ignition problems as the extractor and it's spring started to wear, there are problems with it.

Most autoloaders eject to the right because 80% of us like it that way.
A firing pin changed to 3 o'clock to match up with the extractor would result in a sideways blow to the shell and firearm that would not be real good for accuracy.

A rimfire is ignited at 12 o'clock to keep the firing pin blow in line with the weight of the gun. Changing the extractor position to the top - and redesigning the guns ejection port - would result in a top eject .22. Blowback .22s coming at your face or raining on you will disturb your concentration on the target.
6 o'clock position and you are talking about a bottom ejecting, top feed magazine.

The extraction groove.
Since the .22LR operates at a higher pressure than the .25 auto, you might want to section a .25 case to see how much thicker the brass is at the unsupported extractor groove/primer pocket area (this is the weak spot in the .25 auto that accounts for it's lower pressure and velocity) than a rimfire case is at any point.
For years before the 35gr. bullets were available for the .25 auto, I reloaded mine using the late George Nonte's experiences. High performance that came with the cost of 'one shot' cases that blew out primer pockets every time.
I always felt that a smaller diameter primer for the .25 with steel inserts ala the original .454 Casull cases would have really put the .25 auto in a different light as a carry gun today. But I digress.

By the time you lower velocities -and pressures - to get around the case failure in the extraction groove, even with thickened brass walls, you would have at best a rimfire pellet gun.

By the time the case walls were drawn thick enough to keep from rupturing or expanding and 'seizing' the extractor at current .22LR pressures, you would need to ream the case interior for the .222" bullet as well as to get any powder capacity. You could not just use current .22 drawing methods with a twist for such a cartridge, i.e. LOTS more brass in the shell construction.

Back to Frogo's and 9mm's comments about need and cost.

More sensitively primed rimfires? The same rimfires that all of us mishandle and drop? Are you just kidding or pulling our legs? LOLs on that thought though.

JT
 
So, you are going to make the case manufacture considerably more complicated, and introduce a wildcat catridge that cannot be used in any existing gun, insuring VERY low production numbers for years to come, maybe forever. I'm not an engineer, but it sounds like you have added at least two more forming steps, and two more expensive machines to perform them.

Watch this video: https://www.youtube.com/watch?v=pvK9QlQtrKI You can't make commercial quantities of ammo on a hand press. Maybe slightly smaller versions of those machines are available for a start-up factory, but you're still going to have to pay a pile of money for them, and hire people to install them, run them and repair them when they go down.

Your ammo will either sell at a huge loss to you, or a very high price per round, until you are selling millions of rounds like CCI. I hope you have a large fortune, because by the time this cartridge becomes popular enough to be sold a profit for under ten cents per round, you will have a small fortune.

This illustrates the fallacy that "the rich are job creators." The rich are factory owners. Unless the product is something very expensive like a Porsche or a yacht, jobs in those factories are only created by middle-class customers (and LOTS of them) with fifty bucks in their pocket. Without customers, the jobs go away when the owner runs out of money or the willingness to lose more of it.
 
what a heartbreaker I thought this was going to tell me where to get ammo for my 1903 winchester its ammo was called 22 auto so you might need a new name
 
9mmepiphany said:
How do you foresee igniting the priming compound currently contained in the rim?

What would the striker crush the rim against if you eliminate it's ability to seat against the back of the barrel?
Click to expand...

JT-AR-MG42 said:
With a strengthened extractor system - over most current designs - you might be able to fire such a cartridge using the extractor as the anvil to the hammer of the firing pin.
Click to expand...

JT-AR-MG42 beat me to it - and I see no reason the extractor couldn't be on the top.
 
I acknowledged in the first post that the economy of scale wouldn't allow this to quite as inexpensive as .22lr, but if major manufacturers could utilize the inexpensive manufacturing techniques of rimfires, it seems that an auto cartridge that is 30% the cost of any other auto cartridge couldn't help but be successful in our depressed economy.

How about this idea: same case dimensions as described above, but with a solid rim, a priming anvil pressed in, and priming compound centered in the base. Integrate the primer and case to lower costs. I don't see how forming the brass would add any major manufacturing cost, the profile is probably easier to form than the hollow rim of a rimfire. The anvil would be an additional cost, but not needing to centrifuge every round might offset a portion of that (wishful thinking most likely).
Has anyone ever explored this integrated centerfire primer idea?
 
It almost sounds like you are describing a Berdan primed case

This is the defacto loading system in Europe. They return their brass to the factory to be reloaded
 
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