Glock Gen4 "02" recoil assembly range report

Copied this from my post over at Koolaidtalk as guys over here tend to actually shoot, rather than just wax poetic on how great Glocks are, so I'm betting I'll get better feedback/discussion from you guys...

Got an "02" recoil assembly the other day and got to hit a range yesterday to check it out...

I have a Gen4 G17 and with the recoil assembly that came with it it's seen over 2500rds and has had exactly 3 stovepipes over that round count, 2 of which came from the same batch of known to be soft shooting and inconsistent UMC from wallymart , I'm pretty sure the malfs can be blamed on the combination of shooting cheap wallymart fmj AND the fact that the new recoil assemblies in the Gen4 G17's are on the stiff side for a 9mm.
That said, with the original spring: the gun does shoot really flat (flatter than a Gen3 with a ISMI 15lb spring on an OEM rod), the sight tracking is awesome shot-to-shot, has very little felt recoil, and it has softened up quite a bit compared to when new.

I called and asked for the new softer "02" spring as I want the gun to function as best it can, and in the past over thousands and thousands of rounds I've always run my 3rdGen G17's with ISMI 13's or 15's and found them to run better than with the 17lb stocker that way, so I was looking for the same effect in the Gen4.

Upon install it indeed felt lighter, but not really by much, or nearly as much as I expected it would.

Well, ran 200rds through it yesterday and gotta say I'm kind of disappointed... the effects I was expecting from running a slightly softer spring didn't materialize, quite the opposite actually.

Felt recoil was greater, muzzle flip was increased, and sight tracking was kind of all over the place... WTF? and, I got hit in the forehead with brass on quite a few occasions so it's ejection pattern wasn't any better either, which is not a good sign as a properly sprung gun will throw brass consistently and make a nice neat pile of brass to your right. Also, my trigger that was stellar before the spring switch got noticeably worse with the "02" in the gun as for some reason the lock-up of the gun isn't as tight when at rest with the "02" installed (guess it has something to do with the fact that it's a progressive design were it reacts different at rest then when under recoil).
Yeah, no malfs, but I'm not one of the guys complaining of reliability issues, I think the spring assembly in the new Gen4 is indeed too stiff if someone is expecting it to react just as a 3rdGen G17 would, but since it shoots flatter, softer, and has much better lock-up then the 3rdGen guns, I understand something had to give since you can't get something for nothing, and can live with it as long as the issues are confined to the new guns only being less tolerant of underpowered ammo or a little more sensitive to limp-wristing which is in reality where I feel most of the malfunctions being reported are coming from with the Gen4's.

I reinstalled the original spring as it doesn't take all day to recognize sunshine as they say, no need to waste any more rounds to find out what I already knew (and I brought 500 to the range with me but the "02" was a total bum out so I hung it up after shooting just 200), trigger went back to being awesome and all was well. 200 isn't a lot, I know, I would've shot all 500 and another 1000 if I thought it was worth it, it just wasn't, the difference was obvious, and it sucked.

While the original spring is stiffer, it's strange, there isn't that big of a difference in the feel between racking them back-to-back so much, but the lock-up or rather the initial bit of strength it takes to unlock the original spring from battery is noticeably greater...
While I'm no firearms engineer, I don't think modifying the original spring is going to do it, and don't think this is what the Gen4 G17 owners out there were looking for, these dual-springs are progressive and they work in-tandem with themselves in concert with all their components together as a whole... I think Glock needs to design and manufacture an entirely new spring top to bottom, different rate for the little inner spring, different rate for the outer spring, not just cut down the ones they've been putting in the Gen4 22's and 17's, doesn't feel right and don't think this is the end of it.

Full disclosure, the 02 spring I got looks like it's a pre-production one, the end coils look rough, showing evidence they were ground down from possibly a clipped 01 Gen4 assembly... maybe the production ones will be different (I sure hope so), time will tell I guess.

If anyone else could post their experiences with the "02" springs for the Gen4 here it'd be helpful... hope other guys experiences turn out more promising then mine.

Interesting results as I haven't really followed up on the reports of the new 02 as i haven't felt inclined to do a swap. My Gen4 G17 has just broke the 6K mark and besides a few strange instances in a few hundred rounds, the weapon has been flawless before and in the 3K rounds since that time. As a matter of fact I ran the last 2700 rounds as a torture test along the lines of the stickied post above. No issues what so ever.

I felt so confident in this Gen4 G17, I picked up a Gen4 G22. I have yet to get to testing it out however as I am mostly toying with my new G35 at the moment.

Thanks for your input. I too have a hard time reading at Glock Talk.

Thanks for the report.

You observed increased felt recoil and increased muzzle rise with the lighter spring setup. Which was opposite of what you expected. Did you expect less felt recoil and less muzzle flip with the lighter recoil spring unit? Or something else?

I understand that double captured spring units behave differently than single spring units. They are more like more durable progressive springs supposedly. This may explain the difference vs lighter springs in your Gen 3's. :confused:

Why care about consistent ejection patterns? After tens of thousands of rounds through Gen 1, 2, 3 and now 4 Glocks, I've never observed anything like consistent ejections patterns. Certainly not with any brand of 115 grain fmj training ammo and especially not in the last year as the ammo shortage kicked in.

I know consistent ejection pattern has long been a measure of something, I just don't think that something is particularly important when I consider the incredible reliability of those tens of thou's of rounds in more than a dozen Glocks. Maybe that "rule" was born of perfectly set up 1911s and doesn't apply as much to external extractor designs. My TRP is pretty consistent. First of 9 1911s I've owned that noticeably was consistent but all the rest I've owned were reliable in the extreme also. [shrug] Don't know, barely care.

Interesting report. Thanks again.

The recoil spring has no bearing on the trigger. Not sure why the 02 would feel different.

With Glocks the trigger pull/feel can be effected by recoil spring and striker spring strength.

If the recoil spring gets weak the act of pulling the trigger can actually move the slide slightly out of battery. This is the major reason why I've gone full circle with Glocks and just shoot them with stock striker, FP and recoil springs. This is why if using reduced power recoil springs you have to use a reduced power striker spring.

With both my Glock 17 Gen 4 and Glock 22 Gen 4 I've installed Gen 3 trigger bars and Ghost 3.5lb connectors for much better trigger pulls. On the 17 I bought a Jager aftermarket guide rod and installed a Gen 3 recoil spring on it. I haven't had a chance to shoot it yet to see if it'll work.

I used my Glock 17 Gen 2 at the Topton PA 3man 3gun match since my M&P Pro was giving me issues earlier in the weekend. The Glock ran fine as expected and Team VA Arms took 3rd place.

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http://img.photobucket.com/albums/v4...Robbpistol.jpg
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JHC, yeah, was expecting the opposite of what I got... usually going to a softer recoil spring increases your slide speed and results in less muzzle rise, less felt recoil, and a gun that's less sensitive to limp-wristing, also the sight tracking is usually better too since the action closing doesn't dip the muzzle when coming back on target (like going from a 17lb spring to a 13lb spring in a 3rdGen G17)... I got none of that (a stronger spring will go the other way and usually, while yielding stronger lock-up, will only create problems, like stovepipes incidentally).
Agree also that I may be blowing the importance of throwing brass consistently out of proportion, it's something I'm just used to with the 3rdGen guns I guess, and it's just that if you go lighter or for example to a really light spring, you can throw brass into low earth orbit, again, opposite results here with the 02 spring is all... nothing like what it's like with a 3rdGen.

gotm4, exactly, you explained it perfectly, in the Glock design the striker spring strength and recoil spring strength need to be within a certain range of each other to play nice-nice, yet I've never noticed the difference in trigger feel fall off that drastically without having the gun near the edge of where firing out of battery was a real danger (like say, with an 11lb or a real worn 13lb recoil spring used with a stock strength striker-spring).


...It's weird, almost hard to describe, the 02 spring feels only slightly lighter when working the slide compared to my broken-in original spring that came with the gun, yet the lock-up is far weaker and I could feel the loss in trigger quality immediately, then while shooting it the timing of the gun just felt all "weird"... had to ask myself, if there's no benefit, then why bother with it since the other one felt better?

Sucks to say, but think Glock is just clipping down the existing assembly, and don't think it's doing what they/we hoped it would... they need to engineer a true 9mm-G17-specific dual-recoil spring assembly, but that'll cost them some $$$...

About the slide velocity and flatter handling with light springs . . . that's what I've always understood with more conventional spring setups. Is it different with double spring designs which some say are built that way to have a progressive rate but last longer than progressive springs. I figured there was something to this for the heavier .40 weight Gen 4 spring to shooter flatter in recoil.

Also, from what some have been told by Glock, you may have a pre-prod version.

Yeah, mine's definitely pre-production and actually I have no idea how the dual-spring concept works so who knows...

I may shoot both springs back-to-back today to see if I see/feel anything differently, but just in dry-fire, the trigger getting worse with the 02 spring is already a step back that I don't think I'm willing to take.

Thanks for setting me straight there Rob. I could see the accuracy being affected due to a tighter lockup but didn't see the relationship to the trigger pull difference.

So I disassembled and reassembled the gun swapping between the two springs about 20 times or so, racking the slide and dry-firing it to detect the differences before going to the range... long story short, the 02 spring feels just about the same while racking the slide as the original one that came with the gun and the action just unlocks easier and the trigger just gets worse with the 02 installed. Didn't bother to shoot it.

300 more rounds today without an issue on the original spring, and the gun felt great, sight tracking was great, recoil felt less jumpy than with the 02, and the trigger break was back to being crisp., all leading to me being more accurate...
I've almost lost count, but pretty sure that makes about 1900rds since I've had a malf with the original spring (2 stovepipes around 600-700, 1 stovepipe around 1000) 2900-3000 total, and the gun is just plain better with the original spring in it.
The original spring has softened up a lot to where now it doesn't feel that much tighter than a stock 3rdGen 17lb spring does (I compared it to a new 3rdGen G17 at the shop at the range).
I haven't cleaned or lubed the gun since around 700 or so and it's seen a few sweaty 95 degree days and slimey humid range trips so I cleaned it when I got home today and it was respectably dirty, so I'm not too worried about it's reliability anymore other than that it likes to throw a case at my forehead now and again but that's about it.

I dunno, there it is, tried the 02 spring and it did what it did... what it didn't do is increase the slide speed which is what I was looking for and expected from a "lighter" spring , who knows, it may help or be better in someone's gun that's having issues, but in my gun it just felt like it threw the guns timing off, like I said, I dunno...

If anything I think I've figured out that a dual-spring recoil set-up is more different from a single-spring set-up than I thought.
Just a guess, but if this 02 spring is just the original spring assembly minus some coils off the outer/larger spring, I'd be curious to shoot maybe an "03" spring where they maybe left the outer spring alone and then took a few coils off the longer smaller/inner spring... I think that might be better.