The Down Range Forum
Member Section => Shotguns => Topic started by: Magoo541 on October 30, 2012, 09:52:11 AM
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I've had some time on my hands (bored out of my gourd waiting for other people so I can do my 2 hours of work) and have been thinking about 3-Gun and the shotguns available. The limiting issue for mags seems to be the rimmed 12 guage shells. Anyone ever heard of a rimless 12 Guage? I am sure its been tried, gun guys are tinkerers by nature. But I think it'd be the "bees knees" for 3-gun, just need to get a reloading set-up and a supply of hulls along with a gun and mags. Doesn't seem as impossible a task as it may have been 20 years ago.
Thoughts? Ideas? Comments?
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How would you head space them? You can't use the case mouth. all the other issuses could be fixed.
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When comparing a handgun to a shotgun you run into the issue that a handgun case has a given length. The comparable on a shotgun shell would be the base height. This would mean to go with a rimless shell the gun would need to be hull specific - High base, low base, medium base. It could be done, but it would mean a total mindset change and very limited market.
Question:
What is it about the rim that makes it a limiting factor?
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If you are careful loading, make sure the rim of the cartridge is forward of the rim below it, you'll have no problem as with the .22 rimfires, Coonan .357 and Saiga 12 guage.
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Question:
What is it about the rim that makes it a limiting factor?
When loading mags the issue Tom mentions above is part of it. Another issue is with a rimless design, or a rebated rim, magazines could be relatively straight and possibly double stacked to get the capacity up. I've seen rotary mags that have 4 separate tubes that you can index which is cool but to swap those "magazines" out has to be time consuming where a box magazine would be a lot like a carbine mag change. I've had some time to exercise my Google-foo and everyone is concerned with head spacing but I thought shot guns head spaced of the rim, why couldn't they head space off the base or rebated rim?
This is more a thought excercise that may lead to something else because I'm bored ;D
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When loading mags the issue Tom mentions above is part of it. Another issue is with a rimless design, or a rebated rim, magazines could be relatively straight and possibly double stacked to get the capacity up. I've seen rotary mags that have 4 separate tubes that you can index which is cool but to swap those "magazines" out has to be time consuming where a box magazine would be a lot like a carbine mag change. I've had some time to exercise my Google-foo and everyone is concerned with head spacing but I thought shot guns head spaced of the rim, why couldn't they head space off the base or rebated rim?
This is more a thought excercise that may lead to something else because I'm bored ;D
There needs to be something to physically stop the forward travel of the round at the right place to assure proper headspacing.
Since there are multiple base sizes, the chamber can't be made to have a physical stop for all different lengths.
A rebated rim on a rifle cartridge is to allow something for the extractor to grab. The round would most likely heads pace on the shoulder.
Semi-auto pistol cases like the .45 ACP head space on the front edge of the case. That is why a taper crimp is used on them rather than a roll crimp.
Some cartridges are belted ..a band around the case ahead of where the rim would be. It is used for head spacing...and would probably result in the same issues as the rimed shell when used in a magazine.
Any of these methods would require a new standard for shotgun chambers and the separation of the 'old' design ammo from the 'new'... a major undertaking and potential safety hazard.
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How much ammo do you want to carry? The Saiga 12s seem to have a pretty good rep and have a ten round mag you can get. Much beyond ten rounds of twelve gauge and its going to get heavy, rims or no. I'd rather carry 4 or five mags in a tac vest or the like than have one monster drum type deal. Plus, the saigas are relatively cheap (not so much for the ten rounders though).
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The Saiga can also use a 20 round drum but they were $140/ea last time I checked.
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The Saiga can also use a 20 round drum but they were $140/ea last time I checked.
Yep, and you can load and fire at least four ten rounders in the time takes to reload that drum, plus no reliability issues. I'd rather have several stick mags to one drum any day.
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I'm not recommending it, I'm just saying it's available.
For the price of 3 you could get another Saiga .
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You won't get it to change for 3-Gun. The shotgun market is much too well established. It would be a bigger bust than the 9 MM Federal, or the .45 GAP. The brass itself is much too thin to reliably headspace on. Not only that, but it is not reliable in height now because it doesn't need to be.
It would require an entire new line of ammunition and guns to go along with it. The market would be too limited, and the guns and ammo would be cost prohibitive. Trying to get a new cartridge on the market is a financially risky proposition. Look at the Remington SAUM's, and several of the other short, fat wonder cartridges. Ammo and brass is hard to find, and the guns for them are always heavily discounted because no one wants them.
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The thing that we all missed is that the basic assumption of the OP is wrong.
The limiting factor with shot guns isn't magazine capacity, it's the weight of the ammunition.
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The thing that we all missed is that the basic assumption of the OP is wrong.
The limiting factor with shot guns isn't magazine capacity, it's the weight of the ammunition.
Yep! If you could load fifty you'd have to pay someone to carry it. Its why the army went with the M-16. 5.56 isn't the best ammo in the world, but you can sure carry a lot of it, and if one won't do? It's why you have the giggle switch.
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The thing that we all missed is that the basic assumption of the OP is wrong.
The limiting factor with shot guns isn't magazine capacity, it's the weight of the ammunition.
My original assumption was, and still is, that a rimless shotgun round would work better in a box magazine (which is easier to reload than a tube magazine). With a box magazine like those that the Saiga and the Turkish made MKA-1919 but for a rimless shotgun shell the mags would be less of an arc and double stack may be possible (or even a drum).
As for the weight of the ammunition versus capacity that is what I am addressing through reloading with box mags. Weight on your belt/LBE/back is preferable to a heavy weapon and the more you shoot the lighter it gets ;D
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They already make a 20 round drum for the Saiga.
The crap about rimmed cartridges not working in semi autos is the product of ignorance.
There are many rimmed cartridge semi auto's using box magazines .
Off the top of my head there are the previously mentioned 12 guages, the .22 LR, the Coonan Arms .357 Magnum 1911, and the Russian SVD sniper rifle that uses the same rimmed 7.62X54 as the Mosin Nagant.
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They already make a 20 round drum for the Saiga.
The crap about rimmed cartridges not working in semi autos is the product of ignorance.
There are many rimmed cartridge semi auto's using box magazines .
Off the top of my head there are the previously mentioned 12 guages, the .22 LR, the Coonan Arms .357 Magnum 1911, and the Russian SVD sniper rifle that uses the same rimmed 7.62X54 as the Mosin Nagant.
And lets not forget Desert Eagle. This time its not the need for a new cartridge, just a new shot gun/mag design.An American version of the Saiga. If someone gets it right, I'd expect to see it in a squad car near you. God knows I'd rather see this than a three barreled coach gun. ;D
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You can't do a direct comparision of feeding of rimmed pistol cartridges from box magazines, to the same from shotgun shells. The magazine tolerances for pistols that shoot rimmed cartridges are held much tighter. The rim of a 12 ga. shell is miniscule in comparision. Factor in the sloppy magazine tolerances from injected molded magazines and drums used in the Saiga, and failures to feed abound. It is far easier for a shot shell to jump the rim and cause a hang up in the process, in a Saiga box magazine or drum, than it would be from a Desert Eagle, Coonan 1911, or a S&W Model 52 .38, all of which fire machined rimmed pistol cartridges.
Another problem with the 12 gauge rim is it is basically the result of an upset stamping process, and not a machining process. The reason is because most all shotguns feed from tubular magazines. The rim is basically used for "head space" and ejection only. It doesn't have to be that precise. If you Google Saiga failures to feed you'll get the phone book. No tubular magazine fed shotgun will produce such poor results unless something is physically broken. Many who know the weapon claim around a factory 10% feed failure rate. That is totally unacceptable in any type of self defense or competition shotgun. I'm not saying they can't be made to work. Just don't bet your life on one as they come out of the box.
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GUEA_enUS362US362&q=saiga+shotgun+failure+to+feed