Need dimensional specs for .22LR ammo


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Henry Bowman
March 17, 2005, 03:24 PM
I am working on designing a device for handling rimfire ammunition, specifically .22LR (and maybe later .17HMR). I've searched here and Google (including the SAAMI and ANSI sites). What I want is not reloading specs, but dimensional specs. That is, cartridge length, diameter, rim diameter and depth, etc. I could measure 1000 rounds of several different brands with a micrometer and then take the average, but I figure that SAAMI has already set dimensions (and tolerances) for every commercial caliber.

Can anyone send me a link or tell me where to find this information?


BTW, public and university libraries are full of books on social issues, but not useful stuff like this.

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TMM
March 17, 2005, 05:24 PM
i'm curious- what do you mean "for handling the ammunition"? ammunition carrier? clip loader(ruger made one)?

~TMM

Chipperman
March 17, 2005, 05:41 PM
hmmmm......
That info may not be in the regular reloading manuals since you can't reload .22LR.
I'll check my books when I get home.

Henry Bowman
March 17, 2005, 06:34 PM
I mentioned this once here a few months ago, so I guess the cat's out of the bag (although the invention is not yet complete). I am working on designing a drum magazine for rimfire cartridges (which feed very differently than rimless center fire cartridges.

The goal is the have "semi-disposable" preloaded high capacity (>250 and up to 500 rnds) drum magazines that would fit popular rimfire semi auto rifles (like a Ruger 10/22, etc.). They would be for plinking use only, not self-defense/combat or miltary. For example, I have seen kits to mount 2 Ruger 10/22 actions and barrels together and have it crank operated (kind of like a gatt gun). Not much fun (for very long) with 2 ten round or even 2 25 round mags. Imagine 2 500 round drum mags. Now imagine not having to spend hours and bleeding thumbs to load a thousand rounds into those drums.

The challenges of designing a drum magazine for rimfire cartridges is very different. The closest thing I have found (but is unacceptable) is the American 180 (http://www.american180.com/articles/mgn12-95.html) . I've also search the patent literature, all of which addresses using larger caliber, center fire cartridges. I don't want to design a new gun, just a new king of magazine for a few of the most popular, cheap to shoot, plinkers out there.

There you have it. I've figured out what I think will work functionally. I'm working on calculating dimensions now.

heisler
March 17, 2005, 07:39 PM
What about something like a Calico-style helical magazine?

Chipperman
March 17, 2005, 07:52 PM
"Calico-style helical magazine"

Don't those get boogered up pretty easily from being jostled around after loading?

yesterdaysyouth
March 17, 2005, 08:40 PM
The goal is the have "semi-disposable" preloaded high capacity (>250 and up to 500 rnds) drum magazines that would fit popular rimfire semi auto rifles

do you mean like this??
http://www.centerfiresystems.com/miva/merchant.mv?Screen=PROD&Store_Code=CSI&Product_Code=DRUM-AR

if you get together a working model, i've got plenty of time to load mags :evil: i've even got a test rifle!! :neener:

you might consider contacting CCI/Speer about cartridge specs....

Dave Markowitz
March 17, 2005, 08:44 PM
Bullet diameter: .223"
Neck diameter: .224" (I.e., at the case mouth)
Base diameter: .225"
Rim diameter: .275"
Case length: .595"
Overall ctg. length: .975"

Note: CCI Stingers have a case length of .694" but OAL is the same as .22 LR at .975".

Source Cartridges of the World, 5th ed., page 315.

I do not have data for .17 HRM or .17 HM2.

yesterdaysyouth
March 17, 2005, 08:49 PM
Bullet diameter: .223"
Neck diameter: .224" (I.e., at the case mouth)
Base diameter: .225"
Rim diameter: .275"
Case length: .595"
Overall ctg. length: .975"

i just measured some mini-mags which are dead on these specs...
BTW
rim thickness was .041

Jim K
March 17, 2005, 10:51 PM
Interesting idea, sort of the same thinking as disposable film cans, and now disposable cameras.

My thinking is that if made well they would be too expensive to be disposable and if not made well they would not work. And I think they would have to be disposable; reloading a 500 round drum, even if possible, would just be too tedious an undertaking to be popular.

Now, if someone figured out a way to load the magazine just by dumping in boxes of cartridges, it might be a hit, but then the machine to do that would be pretty expensive.

Jim

Henry Bowman
March 18, 2005, 10:39 AM
Thank you all very much!

Interestingly, my 1st choice would be to have a hopper into which you can dump 500 loose rounds and then it would shake, shift, orient, and feed. That would be a big machine that would require power and all sorts of other things.

The helical drums or mags do not hold enough rounds. Same with the "snail" mag. Those are fine for rimless center fire cartriges. Even rimmed, belted or greatly bottle-necked rounds can be handled up to a point by curving the mag, but that is limited to 25-50, maybe a few more, rounds when being push fed.

Yes, Jim, the trick is to make them cheap (as in low quality and price) enough to be disposable, but good enough to be "reasonably" reliable. That is why it would not be for self defense or combat use, only plinking fun. Every once in a while one might jam or break. If you are just out plinking, you can get your money back. I could not offer a "get your life back" guarantee for other uses.

To share just a bit more, I have determined that it would have to be a two part system. You buy a metal "shell" that includes the spring winder. That would be a one-time purchase that fits your gun. Then you would buy "refill" packs that would be thin plastic that would be preloaded and disposable. Insert, wind, shoot, open to remove empty plastic pack, toss (or recycle). My design would have to be machine loaded and you would mess it up trying to reload it by hand. There would be no reason to anyway. For about $2-$3 more than the price of a 500 round brick of good quality ammo, you have zero handling of loose rounds and zero pushing into mags.

My initial calculations are telling me that 475-500 rounds would be pretty large and that 250 rounds might be a better first target.

Thanks again for all your help and interest. If I get a working prototype, I don't even own a 10/22 so I will need some help there.

yesterdaysyouth
March 18, 2005, 10:49 AM
if you get together a working model, i've got plenty of time to load mags i've even got a test rifle!!

i was hoping you didn't miss that...

mete
March 18, 2005, 12:43 PM
What do you want ? Maximum cartridge -.278 rim dia,.044 rim thickness , case .613, cartridge 1.00, case body .226, bullet .2255 " There is of course max and min cartridge ,and max and min chamber.

Jim K
March 19, 2005, 12:56 AM
If you got the thing working and it really caught on (and no one passes any more laws) you could probably get the ammo companies to pack ammo in your disposable containers. But it would take a lot of persuading unless you could show them potential sales in the tens of millions of rounds. (I think total US consumption of .22 ammo is around 4 billion rounds a year.)

(Too bad I couldn't buy one, but MD has a magazine limit of 20 rounds and it doesn't look like it will be changed anytime in the foreseeable future.)

Jim

possenti
March 19, 2005, 10:50 AM
I'll also volunteer my 10/22 to be the test subject of this noble experiment.

After all, it's for the children.

(Do I get to keep one of the prototypes? :D )

RyanM
March 19, 2005, 03:59 PM
If you build them sturdily enough to be reused several times (but still cheap enough to be "disposable"), you could have customers mail the empty refill cassettes back, for a small discount on their next purchase. Or if these really catch on, you could sell reloading machines (mostly to gun shops, I'm guessing), and the owner can reload cassettes for a small fee.

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