Kill #1 (Goren)
You can tell from [url=http://img162.imageshack.us/img162/9332/goren0ro.jpg]this screengrab[/url], that it is a [url=http://products.berettausa.com/images/immagini_maxi/92FS_S_maxi.jpg]Beretta M92FS[/url].
The real mystery is "Where the hell did Jack get this gun from?"
Kills #2-3 (Chris and Scott)
First I want to admit that I'm not the best with wheelguns. They all look the same to me. However, I was able to recognize that [url=http://img162.imageshack.us/img162/8818/607bg.jpg]the revovler Michelle hands Jack[/url] is the same exact revolver Ronnie gives Kim later in the season, so I took a good screen grab and [url=http://smith-wessonforum.com/groupee/forums?a=tpc&s=884106832&f=530103904&m=2161000721&r=2161000721#2161000721]asked for a little help from the experts[/url]. It's a S&W Model 60 and you'll notice that the handgun Eddie Grant reluctantly hands over to Jack IS a Berettna M92FS Inox.
So, since [url=http://img20.imageshack.us/img20/8067/60andinox8dq.jpg]Jack dual weilds these pistols for kills #2-3[/url], I would put as the weapon "S&W Model 60 & Beretta M92FS Inox" or something similar as you can't tell which gun made the killing shot.
Kill #4 (Eddie)
Of course Jack drops the revolver and just [url=http://img162.imageshack.us/img162/3848/inox4uz.jpg]uses the Beretta M92FS Inox to finish off Eddie[/url].
Kill #5 (Random Terrorist)
Jack takes out the random terrorist with his [url=http://img97.imageshack.us/img97/189/season2kill57dd.jpg]P228 [/url]as seen here.
Kill #6 (Corel Snake Soldier)
If you wanted to know the specific flare gun Jack uses to take out the Corel Snake Soldier, it's a [url=http://www.hkpro.com/p2a1.htm]H&K P2A1[/url], but with [url=http://img20.imageshack.us/img20/6748/flare5po.jpg]the barrel and grip painted orange[/url].
Kills #7-9 (Corel Snake Soldier x 3)
Alright, there are a couple problems with this M15 choice. #1 is that you're linking to an [url=http://www.combatcentral.co.uk/productdetails.asp?PID=122]airsoft web page[/url], which isn't 100% reliable. The real [url=http://www.armalite.com/sales/catalog/rifles/m15a4spr.htm]M15 A4[/url] looks nothing like [url=http://img20.imageshack.us/img20/7643/m4a11wr.jpg]what Jack is using[/url]. Jack is using a gun that either is or is mocked up to look like an [url=http://world.guns.ru/assault/as17-e.htm]M4A1[/url]. It's equiped with [url=http://www.specialoperations.com/Weapons/M4.html]RIS, verticle foregrip, an AN/PEQ-2 laser, and a very busted up ACOG scope[/url].
Kills #10-13, 19 (Hired Gunman x 5)
Jack is back with his [url=http://img90.imageshack.us/img90/9430/season2kills10t13n196kl.jpg]SIG P228[/url] for these kills
Kill #20 (Aimless Kingsley Henchman)
Jack achieves his final kill of the series with the [url=http://img97.imageshack.us/img97/931/season2kill207eo.jpg]SIG P228[/url] before he loses it. :-(
It will be missed...
Kills #21-24 (Aimless Kingsley Henchman x 2, O'Hara, Clueless White Supremacist)
The gun that Jack takes from O'Hara is a [url=http://www.hkpro.com/usp.htm]H&K USP[/url] (Silenced). It is not a USP Tactical as the Tactical has higher sights to accommodate a silencer and the rear sight is adjustable. However, the sights on this gun are fixed and normal size. Hence, for kills #21-24 it's a "H&K USP (Silenced)" You can check [url=http://img102.imageshack.us/img102/594/24season284kd.jpg]this screenshot[/url] right before he makes the kills to confirm that it is indeed a USP.
Kills #26-29 (Aimless Kingsley Henchman x 4)
Hmmm...the H&K G3-SG1 is a good guess, but that's not what this is. You'll notice from [url=http://www.hkpro.com/g3sg1.htm]these pictures[/url] that the G3-SG1 actually has a flash hider on the end of the barrel. But as you can see from [url=http://img102.imageshack.us/img102/4342/24season2108vs.jpg]this screenshot[/url], there is none. Jack is actually using a "HK SR9T" You can [url=http://www.hkpro.com/sr9.htm]see it here[/url], it's the 2nd picture down. The only difference between the stock SR9T and the [url=http://img102.imageshack.us/img102/8830/24season294cw.jpg]rifle Jack is using[/url] is that the rifle in he show is equipped with the traditional HK91 fore grip and bipod, giving it a weird MSG90 with a PSG1 grip...look.