New rifle design: Bottom ejection centerfire rifle.

[coyote trapper1928]

Hi.

     Is it technologically feasible to make a bottom ejecting centerfire rifle ? The Browning BPS shotgun is bottom ejecting, so I was thinking that a centerfire rifle could work the same way.

Any thoughts?

[Mikey]

I believe it has been done already.  I think the Stoner System may have used a bottom ejection system - can't remember now.  And I know there are others that currently use a bottom eject.  Mikey.

[Nobade]

Well, the Stiller drop port does that already. It dosen't really "eject", but it just drops the cases out of a hole in the stock.

[John Traveler1]

Many belt-fed machine gun designs eject empties from the bottom.   This became a natural feature because of the top feed tray systems used.

In sporting rifle designs, the limitation is the tubular magazine feed needed for a bottom-ejection design.  This limits the rifle to using blunt nosed bullets like in lever action repeaters.

[PeterF.]

The FN P90 and PS90 (see http://www.fnhusa.com/contents/tw_p90.htm) have downward eject.  They have mag on top, with cartridges arranged cross-wise.  You don't see many of these (unless you watch Stargate); and it's somewhat controversial because the round is billed as "armor piercing" (and therefore, to some, a "cop killer")

[PeterF.]

As suggested by John Traveller,the problem is "where are you going to put the bullets?"  Most guns have the magazine up from underneath, which would get in the way of your downward ejection. The magazine on top (FN P90/PS90, as mentioned above, the Calico, and the Bren gun) could have a problem with getting in the way of sights, etc.  Those few existing bottom-ejects are tube load (bullets either in front of or behind the action); and, as noted, you can't have pointy bullets in a tube loaded gun ... so you'll see the tube-loaded down-ejects in shotguns (Ithaca, I think) and .22LRs (like the Browning ATD).  If your main reason for going down-eject is to accomodate lefties, gun makers have either chosen to ignore the problem or make a separate left-ejecting version.  I think the Steyr AUG can be switched fairly readily to eject either way. It's an interesting gun-design excercise ... one of the basic issues (similar to "how do you get the trigger action, which happens in front of a pistol's magazine, to the sear & hammer, which are behind the magazine?").

[coyote trapper1928]

Could a rotary style magazine work instead?

[gunnut69]

I don't think the magazine type i.e. rotary or straight is the problem. The problem is that with ejection downward the magazine has to be located on top on the side or front/back. The P90-PS90's and other with the helical mags feed from the top and eject down they do suffer from the mag being in the way of the sighting system and indeed some have the sighting system located on the mag itself.. Not a good idea. The 10-22 action could likely be inverted, the mag inserted from the top and ejection altered to go out the bottom(probably a bit to one side or the other), but why.. Left hand compatable actions are available for most weapons types. Even the AR rifles are now available in a left hand version..

[AeroE]

Install the magazine in the butt, under the barrel, or make the receiver sufficiently wide for the magazine well and ejection port to live sid-by-side.

A magazine with a curved feed could probably be designed so your gun can have a vertical magzine that feeds into the left or right side of the receiver, but it would take some work to get the bugs out.

It's feasible, and I'll bet there is already a patent.

[gunnut69]

I think most agree it could be done and in several ways. Why isn't it BEING done?? Likely because there's no money in it. Without a financial benefit gunmakers can't make the things..