Glock gen4 dual rod springs vs. stout gen3 spring


December 28, 2010, 05:58 PM
I have to ask: is there actually a major advantage of the dual recoil spring set-up of the gen4 series versus the single spring of previous generations if they are equal in strength/power rating (i.e. aftermarket springs for gen 3's equaling the power of gen 4 spring assemblies)? Perhaps a dual spring assembly would not wear out as quickly and perhaps the widened diameter of the gen 4 spring assembly would help reduce felt recoil, but then again it could just be a gimmick...especially considering the options of increasing spring strength of gen 3's with more stout aftermarket springs.

It just seems like an obvious question. It's been a great while since I took physics, but I am having a hard time explaining the advantages of Glock's new Gen 4 dual assembly compared to single (aftermarket) springs of the same overall strength. Can you help me?

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December 28, 2010, 06:10 PM
Give Gaston a call. I'm sure he could help ya...;)


The Lone Haranguer
December 28, 2010, 06:45 PM
It makes some sense in .40-caliber models, whose single spring has a somewhat shorter life. Otherwise, I wonder why they "fixed" something that wasn't broken.

December 28, 2010, 07:37 PM
It simply increases spring service life. A complicated and unnecessary change.

December 28, 2010, 10:09 PM
I am having a hard time explaining the advantages of Glock's new Gen 4 dual assembly compared to single (aftermarket) springs of the same overall strength. Can you help me?

For some time, I ran dual recoil spring set ( in my Gen3 Glock 22. The purpose of the dual recoil spring set is for the secondary stiffer and smaller spring to reduce/prevent the slide slapping hard against the frame to reduce the muzzle flip. The intent is for your pistol to push back without the flip so you can get back on your target faster for faster and more accurate double taps.

From Springco's recoil reducer page (
A secondary, or sub-spring assembly is incorporated onto a heat treated, stainless steel guide rod to cushion the slide to frame impact!
Minimizing slide slap on the frame is hard to do with a single aftermarket recoil spring as the spring rate must be matched to the load for the slide to stop just before it hits the frame but move back far enough to strip the next round from the magazine into the chamber. If you change your bullet/powder/charge load, you may need to buy a different rate spring (many match shooters have several different rate recoil springs for their pistols). With the dual spring set, this is less of an issue and you can still change out the primary spring with a different rate primary spring if your application/match load requires to. Many match shooters will keep tweaking their load/spring until there is virtually no slide/frame slap and their pistol pushes back on recoil.

With high to near max loads needing to meet major power factor, the secondary spring will help with the muzzle flip. With lower loads needing to meet minor power factor, I find that Gen3 stock captured single recoil spring set does a good enough job but will produce pronounced muzzle flip with higher loads like factory JHP rounds. I believe it is for this reason why Glock went to dual spring recoil sets for Gen4 Glocks - to help with recoil of higher powered loads.

Downside of Gen4 dual spring set is that starting to mid range reloads may not reliably cycle the slide and depending on the powder used, you may be forced to use high range load data for most of your reloads. I hope this helped.

December 29, 2010, 07:14 AM
I get the concept of the Sprinco system, but the Glock assembly is different. It is basically made to fit two springs in a length which may be too short for a sufficiently stout single spring...i.e. the compact models when the spring is fully compressed. But when the length of the rod or travel of the slide is sufficient to accomodate full or even less than full compression, a dual system is not physically necessary. Perhaps using two springs could prolong the life of the recoil assembly because the burden is shared, and perhaps having a wider front diameter of the wider recoil spring may help dissipate some of the rearward recoil...But again, physics would dictate that so long as the total spring strength was equal between one spring versus two springs, then neither system should be able to reduce recoil more so over the other. Right?

As for the Sprinco system, I have a somewhat difficult time wrapping my head around it. But then, using physics Sprinco may be yet another unnecessary modification. Conceptually, if one was to run a comparably heavy single spring conventional system, they should be able to enjoy the same benefits of recoil reduction. If the piston of the Sprinco was hydraulic, then things would be different...and probably not all good. But as it is, physically speaking Sprinco may be a bit of over-engineering...maybe.

December 29, 2010, 11:43 AM
Glock has two different dual spring systems. The Compacts (30, 29, 27, 26) have the dual spring system you mentioned where both springs are working during the entire slide cycle.
The new gen 4 system on full size guns is like the Sprinco or HK USP system, the second spring is engaged only at the very end of the slide's cycle.
I've shot the gen 4 Glock 17 and it is a very soft shooter, as is the USP .45 when compared to similar pistols without the dual spring system.

A heavy single recoil spring does not have the same benefits as a dual system. If you increase the single recoil spring's strength to the point where recoil is softened substantially, slide velocity will be reduced to a point where the gun may not be reliable.

With a dual system using a normal strength primary spring, the slide gets good velocity at the beginning of the cycle, and the second spring only engages during the the last 1/8" of travel, reducing the slide velocity just before it hits the frame.
There is a mechanical stop in the dual systems that prevents the secondary spring from acting on the slide until the last 1/8".

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