The primary difference is the sights. The newer 92FS comes with a pretty nice set of white dot sights, while the M9 has slightly smaller, plain black sights.
Some M9's have metal guide rods, but all of the M9's I've dealt with in the Army have had plastic guide rods, same as the 92FS.
Pretty much the same pistol.

You didn't ask, but I'll throw this in as well: The M9A1/92A1? Light rail added at the front of the frame, and a change to the checkering on the grip.

Originally Posted by loper

Some M9's have metal guide rods, but all of the M9's I've dealt with in the Army have had plastic guide rods, same as the 92FS.

Which is the better option to have - metal or plastic??

Conventional wisdom would have the metal guide rod being better. Realisticaly, I've never noticed the difference, and I doubt you will either.
For my part, I don't think it matters which guide rod you use, it'll take several thousand rounds to "wear out" a guide rod. Some other part will probably fail first.

Asked and answered here:

http://www.handgunforum.net/beretta/...ce-m9-92s.html

Originally Posted by Shipwreck

The main and most obvious difference is the rear sight - the M9 has a post on the rear sight, the 92FS has 2 dots (my preference).

But there are a couple of other differences, as per the photos below...

Some of the 92FS models being sold now have a 92FS slide (3 dot sights) and an M9 frame (straight dustcover & non-radiused backstrap).

Well another good thing is you can mix and match em as beretta seems to do from time to time. Great diagram and comparison VA even I got it now. BTW, the M9 will have military type markings and military type serial #'s designations as well.

Originally Posted by denner

Well another good thing is you can mix and match em as beretta seems to do from time to time. Great diagram and comparison VA even I got it now. BTW, the M9 will have military type markings and military type serial #'s designations as well.

The m9 is the military gun? Does the 92fs not get used by the military??

If you followed Va's "Shipwreck's diagram you should have obtained that the differences are very, very minor. For example, I own a 1993 92G civilian model and it sports a straight dustcover as like the M9. All M9/92FS slides and working parts are identical and interchageable in their respective build era.. All the M9 is, is the renamed military version of the 92FS but for the very few differences that have been answered for you. Any military weapon no matter how much civilian it is, will be designated with military lingo at one point or another.You can go to war with either of them and the bad guy probably wouldn't know the difference as probably the soldiers using them as well. So are you going to get the M9 or the 92FS?

Sounds like it will come down to price since they are so similar. Thanks to everyone for helping!!

Originally Posted by loper

The newer 92FS comes with a pretty nice set of white dot sights, while the M9 has slightly smaller, plain black sights.

My commercial M9 has the "dot and post" white sights, as do all the Army-issued ones which I've seen.

One difference which I did notice is that the commercial M9 (like the 92FS) comes with the Hogue Allen-wrench grips screws. The Army-issued M9s I've seen are equipped with straight slot screws (same-same Berettas from Gardone VT).

m9 is the military designation of the 92fs. just like the m16 is the military designation of the ar15. the 92fs or, m9, has evolved in design over the years. a 92f slide will not fit onto a 92fs frame. try it and you will see why.