Button on rifle magazine???

Hey all,

This should be an easy question to answer for someone - 

Last fall I bought a Remington 7600 .243 for my son.  It only had one magazine, so I've been looking on and off for a second one.

I've seen some on EBay that have a button on the bottom left side.  What is that for/what does it do, and can I use a clip like that in the rifle?

Thanks!

Used to have a 742.  Was times when fired 5 shots and needed one more.  Could shove one in the camber and hit the button and was faster than pulling and loading the clip.

Thanks for the answers.  Very logical/reasonable.

So, I ended up buying one.  It arrived yesterday.  I tried it as best I could without actually firing a round, just working the pump to eject and load the shells.

Didn't work so well.  Loaded the first shell fine, but the second one jammed.  Tried it a few times to see if it would happen again, and it did.

Not sure if an actual semi-auto works the action faster than I worked the pump, and that's the difference, or what.

I always figured the reason the action stays open on a semi-auto when it's emptied is more of a safety feature. One glance and you see it's unloaded.

Tim

Ive had it happen, so you can put a bullet right in the barrel and close it and shoot another round faster than taking clip out to reload. 

Thats my take on it. 

I guess I don't see the point in holding the action open on the semi-auto rifles after the final shot.

Anyone who uses one care to explain?

Is it like a pistol, where the slide is locked back to load the first shell of the next clip?

When I first started deer hunting I had a Model 742 (Semi) and the owner of the cottage had the 760 (pump).  Easy way to put it: The clip from a 742 CAN be used on a 760.  However, the clip from a 760, CAN be used in a 742 however, the chamber will not be held open when the clip is emptied.

that's exactly what it's for.

Once the clip is empty, it holds your action open.

Slide that button forward and the action slams shut.

It should work fine in a pump as well.

OK, so I've since learned that those buttons are on clips used in semi-auto rifles to hold the action open after the final shot.

I've never owned a semi-auto, so I've never seen one before.

I'm guessing I wouldn't want to use one in a pump rifle..........