Well, I bought my gen4 19 yesterday and wanted to get out and try it out since it did come with the 03 spring in it. Today at the range it was a balmy 5 degrees so the range session only lasted an hour due to my shooting hand freezing up from a tendon injury 6 years ago (it does not bend well in the extreme cold). Now on with the good stuff, I am an avid collector of the Glock 19 as I currently have 4 of them and have had numerous others in the past. This was due to thinking I needed another gun so I traded and then realizing that the 19 fit my paw the best, I would buy another one. This is one of those lessons to never sell anything that you remotely like! My gen4 19 is like all the others, I brought it home yesterday and cleaned it and the only thing I did was install the glock factory extended slide release. It took alittle bit of getting used to the little grippy things on the grip, but they seem to not bother me after shooting today so I think I like them, only time will tell. Of course my hand was numb so that may it too. My gen 3 gun has had over 12,000 rounds through it and it has served me well since I bought it new in Sept 2001. This gun has been the best shooter so far and it has loosened up really nice over time. I did have the slide coated by CCR in their cera-plate and I love it, it looks awesome and shoots just as well for me. I have replaced the factory glock plastic sights with factory glock steel sights, extended slide release and extended mag release and that is all I have done. Well, today I wanted to actually compare the 2 guns to really see if the newer gen 4 did actually have less felt recoil/muzzle flip as the older gen 3's. I can honestly say that YES, it does have less muzzle flip, the recoil seemed to be the same (maybe alittle different) but with this new dual captive spring, the gen4 felt really tight compared to my broken in gen3 gun. I did this by loading a full magazine in each gun them picking up the gun firing 3 rounds then firing 3 rounds out of the other gun. This was the only way to really tell that there was indeed a difference. The trigger on my gen3 is really broken in nice compared to the new gen4 gun and I think that was the difference in my groups on the targets below. As you can see by the targets below the far left target was shot at 7 yards with the first 10 (5 rnds each symbol) rounds of Blazer 124 grn TMJ out of the ge4 gun. Groups are very nice and tight and I shot them without any bench resting, all free hand. The 2 full size targets I shot 10 rounds at each target (5 rnd of Federal & 5 rnds of Blazer out of each gun totalling 10 rounds) at 25 yards and I did rest my arm on the bench but shot the gun from just my two handed hold. I think that the gen4 group is bigger because of the heavier trigger pull on a new glock. But I do agree that I shoot alittle left with these guns like everyone else does but I really think that it is trigger issue not the gun because if I really concentrate on my teqnique, I can usually get them in there. Ammo that was tested today was Federal Champion 115 grn, CCI Blazer 124 TMJ and Speer Gold Dot 124+P. I had NO, I repeat NO malfunctions in the gen4 gun with the 03 spring. I hope you all enjoy this little write up and I also posted a pic of my 4 19's and my lovely AAC TiRant9! If I think of anything else, I will add it later.