why no other rifles with horizontal mags?


December 17, 2009, 01:43 PM
like the P90...

is it something about the 5.7rnd that makes it work better than others? looking at case dimensions it should work with about any round that has little wall taper... 9mm... 45acp... hell, it could even have a slight curve to it and still probably be functional...

just wondering as i would love to have a rifle that didnt need a mag coming down way below the pistol grip.

maybe im missing something

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December 17, 2009, 01:55 PM
Rotating a round 90 degrees is unnecessarily complicated, IMO.

Not to mention it's strange, different, etc. :)

December 17, 2009, 01:57 PM
it may be, but it seems to work ok....

different yes... but that too is ok. ;)

December 17, 2009, 02:09 PM
I think the main reason is, there is no sporting demand for a high-cap mag 9mm or .45 ACP holding 50 rounds. Most states restrict hunting rifles to 5 rounds or so.

Unless a big manufacture has some expectation of developing military or large law enforcement orders, they just won't expend the resources necessary to do something like that and make it reliable. They already have reliable & cheap box magazines that work just peachy keen.
And there is no military or law enforcement demand for something like that in a pistol caliber.

Not to say some little "niche market" company like Kel-Tec couldn't or wouldn't build a civilian version with limited sales demand, as they could or would.

They just haven't yet.


December 17, 2009, 02:13 PM
fair enough.

i would love... LOVE... to see someone do it in a 22lr ala the MP5 22 clone. (a plinking "fun gun")

unfortunatly i think the 22's rim would cause issues with the mag design...

December 17, 2009, 02:24 PM
See this about that:


Shadow Man
December 17, 2009, 03:19 PM
The P90 isn't a rifle. Like Highorder said, rotating a round 90 degrees is complicated. The more complex a weapon, the more possible it is for things to go wrong with it, and that makes it harder to fix.

A rifle-caliber weapon with a horizontal magazine will, by necessity, have a larger overall width, and therefor be heavier.

However: rifles with horizontal magazines are not a new thing. Think M1941 Johnson LMG. While yes, technically a LMG, it was select fire, and could make single shots, in essence, a rifle. The problem was, the magazine stuck out from the reciever at a 90 degree angle, making the weapon hard to carry on the move, and imbalanced.

Other rifles with horizontal magazines have underbarrel tubes. This limits the use of your rounds though, because pointed bullets can impact the primer of the round ahead of it and cause a very nasty explosion under the barrel of your rifle, right about where your support hand would be.

So it has been tried, and a verticle box magazine located below the bolt has been found to work best. It is a fairly simple matter to change magazines; with practice, it can be accomplished without loosing your sight picture.

Also: I'm sure FN has a patent on their rotating system in the P90. So any rifle with a similar system would have to come from them...

December 17, 2009, 03:40 PM
Calico & Bizon had the helical mags, HK G11 had a similar set up to the FN only its ammo was caseless.

Bizon's magazine was mostly replaced by the old stick mag (more reliable) from the PPSH43.

If it ain't broke, don't fix it.

December 17, 2009, 04:31 PM
i would love... LOVE... to see someone do it in a 22lr ala the MP5 22 clone. (a plinking "fun gun")

That'd be the GSG-5

is it something about the 5.7rnd that makes it work better than others?

It's short. Doing the same thing with a 5.56mm rifle would make the weapon 3.5+ inches wide.

As for the P-90 itself, FN could have used a conventional magazine and employed their ingenuity elswhere-like making the gun lighter. Personally, I feel that a PLR-16 with a retractable stock and FA capability would have it all over the P-90 as a PDW. Just my $0.02.

December 17, 2009, 05:48 PM
i would love... LOVE... to see someone do it in a 22lr ala the MP5 22 clone.

get an American Arms 180, add the laser and shoot through cinder block and steel plating with a .22lr

December 17, 2009, 05:51 PM
Robinson offered a top feed version of thier C96-- looked like a small Bren. It had off sight sigts and was reported to be reliable as heck-- I think the MSRP was around $1800 in 2006--- wish I would have spent my tax return that year on something other than beer...

December 17, 2009, 07:43 PM
Lewis Gun - Horizontal pan magazine

Calico Light Weapons Systems
Calico 9mm carbine


Owen SMG

Horizontal, Vertical, Helical, Pan, just about orientation you can imagine has been tried. Many times they fit a need that could not be fit any other way. Stacked magazines are used because the length of the magazine isn't critical until it gets around 30 rounds, I suspect.

December 17, 2009, 07:47 PM

H&K G11

Monarch P-12 12gauge pump shotgun

American 180 SMG

December 17, 2009, 09:33 PM
The patent on the P90’s feed system expired about a year ago. Perhaps we’ll see it utilized on some more designs.

Where's the guy with the magnetic mag spring? Looks like a match made in heaven.

December 17, 2009, 10:04 PM
i had thought so since it had been around for so long, hence my daydreaming about something similar.

thanks for all the input! :)

December 17, 2009, 10:39 PM
Keeping the magazine in the same plane as the stock and/or grips keeps the rifle narrow, making it easier to store, sling and carry in shooting position.

December 17, 2009, 10:47 PM
yes if the horizontal mag is like the Sten or Bren....

but the P90 is not an unwieldy or overly wide weapon. add 1.7cm in mag width for a 223 round.... subtract some for a pistol caliber.

honestly if you look at the P90 mag its not overly complicated to rotate the round 90 degrees and i havent heard of a lot of probs with the mags....

December 19, 2009, 03:21 PM
Great pics from 4th Point of Contact. Helps those of us that haven't seen these weapons get a better perspective on the topic of thread!

Shadow Man
December 19, 2009, 07:20 PM
add 1.7cm in mag width for a 223 round

5.7x28mm round vs. 5.56x45mm round...I'm no math wizard, and haven't run the numbers yet, but something tells me you would have to add far more than 1.7cm...


Please feel free to correct me if I am wrong though.

December 19, 2009, 07:24 PM
sure. 1.7cm = 17mm.


i went off OAL measurements i found on the web, i dont have access to the 5.7x28 rnds

Shadow Man
December 19, 2009, 07:38 PM
Meh, I guess if I was really smart I could get the ruler out of the desk and measure the damn things...and yes, that accounts for case lengths, sure, but what happens when you start adding different bullet weights for the 5.56? Remember, GI mags for the M16 are not perfectly sized, there are loose tolerances to allow for more reliable feeding. That's why you may see a soldier tap his mag against his helmet; to make sure that his rounds are all seated correctly. So your mags are going to be pretty wide, to allow for all of that. Secondly...I mean, I'm sitting here looking at my 30rd GI mag, holding it sideways and trying to imagine a gun that wide...it'd be about as bulky as a 249 or a 240B...I'm not saying it can't be done, just...it could be tough.

December 19, 2009, 07:39 PM
^^^that math is correct

Shadow Man
December 19, 2009, 08:00 PM
Yes indeed, I see that it is, and I stand corrected.

December 19, 2009, 08:35 PM
Fallschirmjägergewehr 42


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