And is IAI a good brand....
www.thehighroad.org/showthread.php?s=d25d24d8aa392bb5c93cd39fa987cee1&postid=1301893#post1301893

My Winchester does not hold open bolt.  YMMV.

huh? is it standard or not?

If you push the button, i will stay open.

there's REALLY no BHO?!?!?!?!

If you're referring to a last shot bolt hold open, then no. The 30 round Mags have a follower that acts as a bolt hold open device but when you remove the Mag, the bolt goes into battery. Otherwise the slide has a manual bolt hold open built into it.

I don't know anything about the IAI Carbines.

interesting.  so the thirty rounders hold the bolt open, then you'd hit 'the button' (?) to keep it open...
How do you release?

More info.

The standard 15 round magazines do not hold the bolt open when the last shot is fired.
The standard 30 round magazine has a notch on the mag follower that catches the bolt and holds it open when the last shot is fired, but when the mag is removed, the bolt snaps shut.

On the top of the op rod handle is a small pin-like bolt latch.

When you pull the op rod all the way back, you press the pin down and HOLD it down, while you ease the op rod forward until it catches in the small notch on the lower receiver rail.

This is strictly a bolt hold-open for cleaning, and a bump will cause the latch to disengage and the op rod to run forward.

To release, you just pull the op rod back slightly which disengages the latch.