Now I remember that there was a reason I didn't come here often to post - although I do come and lurk occasionally, or look up information.
I have gotten more insults here in one post than in THOUSANDs of posts on more adult, civil firearm forums - feels just like Junior High. Fortunately, I have a thick hide, I know what I know and that appears likely to be a bit more than most people who are inclined to reply to strangers with an insult instead of reason. A bit Sensitive about "Glock Perfection", are we? After I personally changed out about 30 Model 22 frames for frame tab defects, (my agency changed out over 100 frames in total) I got over the slogan.... I
do like my personal 20 and 22 Models, but I am under no illusion that anything build by the hand of Man is
perfect.
As a Glock Armorer for over ten years (as well as a Remington Factory Trained LE Armorer and Colt AR Armorer), and an IPSC and Service Rifle competitor, and an FBI trained Firearms Instructor, let me point out a couple of things.
My question was sincere - I wondered if anyone here might actually
know why the heavy spring - when
nothing else in 9MM seems to need it. My point is that the heavy spring serves no necessary purpose and is thus a negative - the newer is less "user friendly" and more difficult to operate than the old. Seems counterintuitive.
I fired the original Glock Model 17 the very first month it came out in the US and it was easy and quick to manipulate and impressed me (though only a 9) - and I was a pretty good IPSC competitor with tuned 1911s in 10MM (also 20lb dual springs) and .45 at the time.
Secondly, Center fire Glocks (I am leaving out the new .22) ALL have LOCKING BLOCKS, children. I just pulled my new Gen 5 M17 out of my duty holster and looked at it while scratching my head from the posts above - even though I know that from cleaning it. At least I know how all my guns work and what the parts are called. And we are required to be
well over 300 rounds (in our first day's range session) before we would ever be allowed to carry a brand new issued pistol.
The recoil spring's job is to return the slide, pickup a round from the magazine and lock the pistol - a locked breech pistol can be fired without the recoil spring (at least a 1911 can) without harm - it just won't cycle - the locked breech takes the pressure, and unlocks after the pressure drops. The recoil spring is not a substitute for a locked breech.
If the original Model 17 that made Glocks popular got by on half the poundage ( and most other 9MMs on the market do as well) I was merely commenting on the oddity of unnecessarily making the "newer and better" model
noticeably harder to use - particularly when Glocks are frequently Department Issued to the "lowest common denominator" average new officer, whether 5'2"/90 lb. or 6'6"/220.
A light round like the 9MM does NOT need a dual recoil spring - while a Glock 20 or a Delta Elite in 10MM certainly should have one. An unnecessarily stiff spring does not make a pistol "better" in any way - except, perhaps, as a maintenance thing, you should not have to change it as often. We used to change our Model 22s spring assemblies at 3000 rounds. My understanding is that the double spring may go to 6,000 - and that could be Glock's reason. That is an accountant's reason - not a using street officer's.
Part of my training was to learn to reload and manipulate a handgun with only one hand (hands get hit in gunfights, or you may be holding a door, child, etc.), and a heavy slide makes that near impossible. Give it a try and you might see my point.
But from what I see here, if Gaston Glock did it, it should NEVER, EVER be Questioned....
Well, Cheers and best wishes to all, anyway.

CC