Any market for a rimless shotgun shell?

Nickel Plated · November 13, 2013, 08:42 PM

Just curious if anyone would be interested in rimless shotgun shells? What would be some advantages to them?
I guess they would be good for box and drum fed shotguns like the Saiga since box mags generally don't like rimmed ammo too much.

I just have an idea for making rimless shells that would be cheap and easy to make using standard shotgun shells and any current shotgun made for standard shells would be easily (and reversibly) retrofitted to use the rimless ones.

Probably pretty pointless with current shotgun designs since they are all designed from the ground up to work well with rimmed shells, but could open possibilities for interesting future designs.

**Mike Irwin** · November 13, 2013, 09:37 PM

The most important role of the rim on a shotshell is to maintain headspace. If you don't have a rim, you either have to headspace on the case mouth, which is extremely problematic with a shotshell, or you need to have a shouldered shell, which brings its own problems with it.

Nickel Plated · November 13, 2013, 10:07 PM

Well in this case the shell will headspace using the mouth of the shell against the front of the chamber, like your typical handgun round. Or perhaps a more accurate description, it will headspace like a belted case except the belt runs most of the length of the case (stopping where the crimp begins on the fired shell.

Here's a quick gist of the design. You take a standard rimmed shell. And put a tube around it like a sleeve that brings it's diameter up to the next largest gauge. Or any larger size really, I'm just suggesting the next larger gauge to stick with standard, readily available components. The sleeve extends from the very front of the unfired shell to just a bit before the rim, leaving enough space between the sleeve and the rim for the extractor to grab. The sleeve would be thick enough that the overall diameter of the new shell would be larger than it's rim, essentially giving you a rimless case.

For example, you take a 20 ga shell, slip a sleeve over it that has the inner diameter of the 20 ga and the outer diameter of a 12 gauge. The only downside I can see is you now have a shell the size of a 12 gauge with the payload of only a 20. Though this is the simple expedient version. If you were to specifically manufacture this from scratch then you could maintain the 12 ga payload.

To make an existing shotgun work with this. You would use a 12 gauge gun (really just for the 12 ga mag tube), swap the bolt with a 20 gauge bolt for the right size bolt face and extractor. And take a 20 gauge barrel, but ream the chamber (only the chamber, not the whole bore) to 12 gauge diameter. Thus you now have a barrel where the chamber steps down from 12 gauge to a 20 gauge bore. That step is what the sleeve of your case head spaces against.

Like I said, this is mostly a solution in search of a problem, but would be an interesting thing to try nonetheless. Could be a fun project for an old unneeded shotgun someone might have lying around. The only permanent modification is to the barrel. And if you want to return the gun to a standard shell, just buy a new barrel and swap the bolt back to the original gauge.

Vertigofirearms · November 13, 2013, 11:40 PM

Intrepid's RAS-12:

Proprietary Upper with proprietary munition = CRAP

Chaz88 · November 13, 2013, 11:48 PM

I think it is an interesting idea but do not see much practical use in retrofitted shotguns. But if you can build a better mouse trap...

Virginian · November 14, 2013, 01:47 AM

Unless you can build it cheaper than the competition it will fail. And the shells have to be cheap too.

**Mike Irwin** · November 14, 2013, 10:41 AM

"Unless you can build it cheaper than the competition it will fail. And the shells have to be cheap too."

That's the thing...

You can build a better mousetrap, but it does NOT guarantee that anyone is going to beat a path to your door.

The land of futility is littered with the corpses of products that were better than their established counterparts but which just couldn't knock the tried and true product out if the slot it had occupied for so long.

BigJimP · November 14, 2013, 12:02 PM

If your premise is that box mags don't like rimmed shells much....then the question is, what is the number of shotguns out there being sold or in service today, that have box mags...?? ....and does that number of shotguns represent 1% or 10% - of the shotguns in service... ( I'm not sure )...but I think the number is really small ( maybe less than 1%..).

....and I don't know that its really true that box mags don't like the rimmed shells.../ - and even if they don't, maybe you should consider improving the box mags for shotshells to fix the issue...
-----------------------
If Defense is your focus on shotguns...my hunch is that most of the guns sold are pump guns.../ with a small percentage of semi-autos ( like Benelli M-2's, or M-4's - but they're more money than a lot of folks want to spend ) / and I don't know where the box mag guns fit into the mix....

For bird hunters - clay target shooters...box mag guns have no market. Max is 2 or 3 shells -- depending on what you're doing...

...in terms of shotguns that get shot the most - a single bird hunter or clay target shooter, by far, will put more shells thru their guns in a month ( maybe 1,000 shells a month ) --- which I think, is typically more than 20 or more tactical shotgun folks will put thru their guns in several months probably ...

...and selling shells - is both about usage / as well as how many shotguns are out there with box mags...

but just my perspective...( I'm in the bird hunter / clay target shotgun usage category -- with about 15 shotguns in 12ga, 20ga, 28ga and .410 ) - and while I have a few pump guns / that could be used for Tactical shooting - its just not my focus, so maybe I'm off base here....

Nickel Plated · November 15, 2013, 07:28 PM

Yea I will admit there doesn't seem to be much point in this unless you can come up with some significantly better shotgun design that will just not work with a rimmed shell. I was never one to think of practical gun designs. Just cool oddball ones.

Too bad the only shotgun I have now is only available in 12 ga so I can't get the parts needed to try this out.

If I spot a used pump for really cheap though, I will definitely snag it up just to screw with it.

Vertigofirearms: Regarding the RAS-12. Well it's crap because like you said, too much proprietary stuff. My idea would work with any off the shelf shotgun, using off the shelf parts with only a barrel that would need the chamber reamed (likely need a gunsmith for that, unless you can do such work yourself)
And the shell can be easily and cheaply made by converting any standard shotgun shell.

BigJimP · November 15, 2013, 07:37 PM

Cool oddball stuff is ok .....but I don't know about this ....

I wouldn't spend all your retirement funds developing it ...

..(just in case)...

Vertigofirearms · November 16, 2013, 12:22 AM

Quote:

My idea would work with any off the shelf shotgun, using off the shelf parts with only a barrel that would need the chamber reamed

I do not know the exact specifics of your idea, but I believe retrofitting would not work "with any off the shelf shotgun" and here is why:

1.) Magazine tubes and shell stops would need to modified.

2.)You would have to modify the existing extractor to grab on to the new cartridge. Ejector may also need to be modified.

3.)If you modify crap ammo, you will still get crap ammo. If you modify performance ammo, you wasted ammo.

November 13, 2013, 08:42 PM	#1
Nickel Plated Senior Member Join Date: January 17, 2010 Location: Brooklyn, NYC Posts: 610	Any market for a rimless shotgun shell? Just curious if anyone would be interested in rimless shotgun shells? What would be some advantages to them? I guess they would be good for box and drum fed shotguns like the Saiga since box mags generally don't like rimmed ammo too much. I just have an idea for making rimless shells that would be cheap and easy to make using standard shotgun shells and any current shotgun made for standard shells would be easily (and reversibly) retrofitted to use the rimless ones. Probably pretty pointless with current shotgun designs since they are all designed from the ground up to work well with rimmed shells, but could open possibilities for interesting future designs.

November 13, 2013, 09:37 PM	#2
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,380	The most important role of the rim on a shotshell is to maintain headspace. If you don't have a rim, you either have to headspace on the case mouth, which is extremely problematic with a shotshell, or you need to have a shouldered shell, which brings its own problems with it. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

November 13, 2013, 11:40 PM	#4
Vertigofirearms Junior Member Join Date: March 14, 2013 Posts: 12	old news, already exists Intrepid's RAS-12: Proprietary Upper with proprietary munition = CRAP __________________ Lover of all things Benelli.

November 13, 2013, 11:48 PM	#5
Chaz88 Senior Member Join Date: January 4, 2010 Posts: 1,243	I think it is an interesting idea but do not see much practical use in retrofitted shotguns. But if you can build a better mouse trap... __________________ Seams like once we the people give what, at the time, seams like a reasonable inch and "they" take the unreasonable mile we can only get that mile back one inch at a time. No spelun and grammar is not my specialty. So please don't hurt my sensitive little feelings by teasing me about it.

November 14, 2013, 01:47 AM	#6
Virginian Senior Member Join Date: February 11, 2012 Location: Williamsburg, Va. Posts: 1,528	Unless you can build it cheaper than the competition it will fail. And the shells have to be cheap too. __________________ What could have happened... did.

November 13, 2013, 10:07 PM	#3
Nickel Plated Senior Member Join Date: January 17, 2010 Location: Brooklyn, NYC Posts: 610	Well in this case the shell will headspace using the mouth of the shell against the front of the chamber, like your typical handgun round. Or perhaps a more accurate description, it will headspace like a belted case except the belt runs most of the length of the case (stopping where the crimp begins on the fired shell. Here's a quick gist of the design. You take a standard rimmed shell. And put a tube around it like a sleeve that brings it's diameter up to the next largest gauge. Or any larger size really, I'm just suggesting the next larger gauge to stick with standard, readily available components. The sleeve extends from the very front of the unfired shell to just a bit before the rim, leaving enough space between the sleeve and the rim for the extractor to grab. The sleeve would be thick enough that the overall diameter of the new shell would be larger than it's rim, essentially giving you a rimless case. For example, you take a 20 ga shell, slip a sleeve over it that has the inner diameter of the 20 ga and the outer diameter of a 12 gauge. The only downside I can see is you now have a shell the size of a 12 gauge with the payload of only a 20. Though this is the simple expedient version. If you were to specifically manufacture this from scratch then you could maintain the 12 ga payload. To make an existing shotgun work with this. You would use a 12 gauge gun (really just for the 12 ga mag tube), swap the bolt with a 20 gauge bolt for the right size bolt face and extractor. And take a 20 gauge barrel, but ream the chamber (only the chamber, not the whole bore) to 12 gauge diameter. Thus you now have a barrel where the chamber steps down from 12 gauge to a 20 gauge bore. That step is what the sleeve of your case head spaces against. Like I said, this is mostly a solution in search of a problem, but would be an interesting thing to try nonetheless. Could be a fun project for an old unneeded shotgun someone might have lying around. The only permanent modification is to the barrel. And if you want to return the gun to a standard shell, just buy a new barrel and swap the bolt back to the original gauge.

November 14, 2013, 10:41 AM	#7
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,380	"Unless you can build it cheaper than the competition it will fail. And the shells have to be cheap too." That's the thing... You can build a better mousetrap, but it does NOT guarantee that anyone is going to beat a path to your door. The land of futility is littered with the corpses of products that were better than their established counterparts but which just couldn't knock the tried and true product out if the slot it had occupied for so long. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

November 14, 2013, 12:02 PM	#8
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	If your premise is that box mags don't like rimmed shells much....then the question is, what is the number of shotguns out there being sold or in service today, that have box mags...?? ....and does that number of shotguns represent 1% or 10% - of the shotguns in service... ( I'm not sure )...but I think the number is really small ( maybe less than 1%..). ....and I don't know that its really true that box mags don't like the rimmed shells.../ - and even if they don't, maybe you should consider improving the box mags for shotshells to fix the issue... ----------------------- If Defense is your focus on shotguns...my hunch is that most of the guns sold are pump guns.../ with a small percentage of semi-autos ( like Benelli M-2's, or M-4's - but they're more money than a lot of folks want to spend ) / and I don't know where the box mag guns fit into the mix.... For bird hunters - clay target shooters...box mag guns have no market. Max is 2 or 3 shells -- depending on what you're doing... ...in terms of shotguns that get shot the most - a single bird hunter or clay target shooter, by far, will put more shells thru their guns in a month ( maybe 1,000 shells a month ) --- which I think, is typically more than 20 or more tactical shotgun folks will put thru their guns in several months probably ... ...and selling shells - is both about usage / as well as how many shotguns are out there with box mags... but just my perspective...( I'm in the bird hunter / clay target shotgun usage category -- with about 15 shotguns in 12ga, 20ga, 28ga and .410 ) - and while I have a few pump guns / that could be used for Tactical shooting - its just not my focus, so maybe I'm off base here....

November 15, 2013, 07:28 PM	#9
Nickel Plated Senior Member Join Date: January 17, 2010 Location: Brooklyn, NYC Posts: 610	Yea I will admit there doesn't seem to be much point in this unless you can come up with some significantly better shotgun design that will just not work with a rimmed shell. I was never one to think of practical gun designs. Just cool oddball ones. Too bad the only shotgun I have now is only available in 12 ga so I can't get the parts needed to try this out. If I spot a used pump for really cheap though, I will definitely snag it up just to screw with it. Vertigofirearms: Regarding the RAS-12. Well it's crap because like you said, too much proprietary stuff. My idea would work with any off the shelf shotgun, using off the shelf parts with only a barrel that would need the chamber reamed (likely need a gunsmith for that, unless you can do such work yourself) And the shell can be easily and cheaply made by converting any standard shotgun shell.

November 15, 2013, 07:37 PM	#10
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	Cool oddball stuff is ok .....but I don't know about this .... I wouldn't spend all your retirement funds developing it .....(just in case)...

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