Quick question... Is the A2 front sight post plunger spring the same as another spring on the AR? Need to replace mine, but missing that spring (yet have lots of other AR springs). Thanks for any info!

Yes, go for it.

Huh? I meant, is there any other part that uses that same spring (so I can pirate my spare spring stash)?

Sorry. I replied thinking the A1 and A2 using same parts...

I don't believe the spring is same as another used in the rifle. Front& rear takedown springs are the only ones that come to mind as being same as each other.

try a few of your spares and see what happens. All it has to do is keep the plunger pushed tight against the notches on the sight post so I think you could improvise with another.

ETA. I just went through my spare parts box. None of the springs are an exact match for the front sight spring, the closest thing is the ejector/safety detent spring. The ejector spring is a little longer so it would need to be cut down a bit, but the biggest problem is the ejector spring is thicker and doesn't compress as easily.

Thanks for the info! I just went ahead and ordered the proper spring instead of modifying a different one. Peace of mind kind of thing.