How Does an AR-15 Eject Casings

[CmdrSlander]

I understand how a bolt action and a pistol eject casings, but what wills the casing to fly clear of the gun on something like an AR15 or M14? I'm sure this is a silly question but I watched a lot of detailed firing animations and I even have an AR yet I'm still puzzled.

Edit: I understand that the bolt moves to the rear when the gun is fired, thus exposing the casing to the ejection port, I'm wondering what makes the casing then fly clear of the port. Is it gas pressure? The magazine's spring?

 

[Destructo6]

There's a spring-loaded plunger (the ejector) on the face of the bolt, opposite the extractor claw. AR and M1/M14 style rifles use this type of ejector.

 

[matrem]

The ejector is pushing "hard right" at all times. With the case held by the extractor on the right & being pushed at the bottom left by the ejector, once that case finds the escape route:
Presto

 

[CmdrSlander]

Thanks guys

 

[sugarmaker]

And, depending on bolt velocity, the case bounces off part of the receiver and lands in front of the gun somewhere. Exactly where depends on the load. Very consistant wihin a given load, but lots of variation between different loads.

 

[OhioChief]

that was a great question. I have 4 AR15, 3 I put together myself. And yet I really didn't understand exactly how that worked. Thanks!

 

[Elkins45]

I understand how a bolt action and a pistol eject casings

Some bolt actions (Savage for one) eject their casings the same way an AR does.

 

[CmdrSlander]

Reply to Above

I know how the specific bolt action rifles I'm familiar with eject casings...

 

[Elkins45]

I'm guessing that those rifles are ones like the Mauser 98 where there's a slot cut in one of the bolt lugs and there's a blade ejector that hits the case head and knock it out of the action. I think the Winchester 70, both old and new, work the same way.

AFAIK those are the only two types of ejection systems in wide use--either a spring loaded plunger or a fixed blade ejector. If here are others I either haven't encountered them or (equally likely) haven't paid attention. Anybody want to chime in and tell us if there's a third method of case ejection that's common?

It just occurred to me that I don't know how the common lever action guns (Win 94 and Marlin 336) eject their casings. Anyone want to educate me on that?

 

[jerkface11]

My Olympic 9mm AR has a slot cut into the bolt. A spring fixed to the receiver pokes thru the slot and ejects the cases.

 

[Destructo6]

AFAIK those are the only two types of ejection systems in wide use--either a spring loaded plunger or a fixed blade ejector.

The HK roller guns use a weird hybrid that sees the ejector pivoting in the removable gripframe (in the trigger pack). So, as the bolt carrier moves to the rear, it rocks the ejector up into the ejector slot of the bolt head, sending the spent case into the next time zone.

Odd German stuff, eh?

 

[rcmodel]

I don't know how the common lever action guns (Win 94 and Marlin 336) eject their casings. Anyone want to educate me on that?

Marlins all use a flat spring ejector held in the left receiver wall. It pops out as the bolt slides past it and knocks the case out the side.

Winchester 92's & 94's use a spring loaded ejector in the bolt that flips them out vertically when the round or case clears the front receiver ring.

rc