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When the USP came out in the early 90s, its recoil reduction system was touted as a key design feature. However, every HK gun released after USPf had a plastic buffer instead of the dual spring setup. I always assumed that they had trouble fitting the dual spring assembly into more compact guns like USPc and P2000, but the upcoming HK45 also has a plastic buffer, despite being even larger than the USP. So this got me thinking - is the USP recoil reduction system all hype, or too expensive to produce (compared to the plastic buffer)? Or is there some other explanation?
 

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Trimming down the width is the objective on the successive models after USPf to make them feel less boxy, that is most likely the reason why they have to discard the dual recoil spring set-up. Compromises? Probably. But it makes them more user-friendly. P2000 ergonomics seems better than the USPf.
 

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Some shooters claim that the dual spring recoil reduction system causes unpredictable and unconsistent recoil forces making fast follow up shots harder than the competition. The articles I have read on the new comer HK45 have mentioned this issue and claiming that the changes in the recoil reduction system were made to achieve more consistent cycling to enhance fast follow up shots performance.
Best.
 

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In SK version there is not enough place under the barrel to put a spring that holds adequate amount of coils to work against the high pressure ammo. So it is a kind of necessity to use dual recoil spring.
On the other hand SK pistols are not designed to perform as their bigger brothers. SK pistols offer you anywhere / anytime kind of protection with some kind of compromise in full size performance, which is the least in HK pistols.
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Some shooters claim that the dual spring recoil reduction system causes unpredictable and unconsistent recoil forces making fast follow up shots harder than the competition. The articles I have read on the new comer HK45 have mentioned this issue and claiming that the changes in the recoil reduction system were made to achieve more consistent cycling to enhance fast follow up shots performance.
Best.
I dont see how force divided by the two same springs every shot on over round could vary more than the same shot on one spring, and if by some chance there is some variation I highly doubt that humans have fast enough reflex times to even notice it. Do you have any additional information on this, it seems like BS marketing to me, but then again Im no expert.
 

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The P2000SK has the dual spring set up with the same reason it's used in other subcompact guns, because the single spring does not effectively deal with the recoil force over such short distance that slide is traveling. So dual force is used to retard the recoil and then finally stop the force at its peak level.

As for the dual spring pro/con. I've heard about the inconsistency on the dualspring set up, but it's never been substantially proven other than what shooters say. Personally I haven't had any issue with it. The USP is one of the softer shooting 9mm I have. (It'd be the "perceived" softest shooting gun if not for the higher bore axis).

As for pros of the set up. The original Mk23 design used the dual spring because it's more effective in absorbing recoil forces even when firing the special Mk23's 45acp ammo that blows through ship bulkheads. This is because the 2nd spring comes into play to slow down the slide. The USP inherited the dual spring design originally because it's designed as a 40cal gun, probably to remove some of the "snap" in 40cal which is more sudden than 9 or 45. In a 9mm and standard 45acp, the dual spring is probably not needed. It's more complex and also more expensive. That's why you don't see it implemented. Apple to apple, I'd imagine dual-spring extends the gun's life compared to single spring design.
 

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Good thread.

I'm more than a little upset that the HK45 will not be using the MK23/USP dual recoil spring setup.

IMO, the polymer buffer doesn't perform nearly as well as the dual spring design.


Of course, the above should in no way be construed as unwillingness to purchase the HK45. In fact, I'll be waiting on it to hit the shelves.
 

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Good thread.

I'm more than a little upset that the HK45 will not be using the MK23/USP dual recoil spring setup.

IMO, the polymer buffer doesn't perform nearly as well as the dual spring design.


Of course, the above should in no way be construed as unwillingness to purchase the HK45. In fact, I'll be waiting on it to hit the shelves.
And thats probably what they were counting on. They are golden no matter what they choose to change or leave out.
 

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I dont see how force divided by the two same springs every shot on over round could vary more than the same shot on one spring, and if by some chance there is some variation I highly doubt that humans have fast enough reflex times to even notice it. Do you have any additional information on this, it seems like BS marketing to me, but then again Im no expert.
The second spring on the USP guide rods don't come into play until the last part of the travel due to the way it is designed. If you want to feel the resistant of that second spring, pull the slide back normally till it stops. Now, continue to pull it back much harder. That's where the second spring comes in.

You can notice the difference, but it's more visual than tactile. When you get to that state in your shooting ability where you can see your sights lift and also track your sights as it is cycling, where everything appears in slow motion. That's when you start seeing the subtle differences in gun performance and even spring weights.
 

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It's also been said that 2nd spring makes the slide travel at a rate different from traditional gun, as if the slide hesitates (which is the reason the gun shoots softer). And this difference is what makes people feel inconsistent, especially if they also shoot other guns.
 

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The second spring on the USP guide rods don't come into play until the last part of the travel due to the way it is designed. If you want to feel the resistant of that second spring, pull the slide back normally till it stops. Now, continue to pull it back much harder. That's where the second spring comes in.

You can notice the difference, but it's more visual than tactile. When you get to that state in your shooting ability where you can see your sights lift and also track your sights as it is cycling, where everything appears in slow motion. That's when you start seeing the subtle differences in gun performance and even spring weights.
Do you consider this a handicap? If so, considering that this is a service pistol for police and military if you could redesign the USP series would you incorporate a single spring or dual spring design?

From what you are saying I could see how in competition like IPSC etc it could slow you down, but for combat accuracy as it was designed I have a hard time imagining this could be an issue. Like you said, Im just not at the level of experience where I could see this for myself.
 

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Isn't the goal of combat shooting to put as many rounds as necessary in the shortest amount of time to stop the attacker? The only difference between combat and competition is the targets don't shoot back. Go over to the sandbox right now and you'll be surprised how much competition gear is being used in combat.

For a combat gun, KISS. USP guide rod has 8 parts. Go with a standard spring while keeping it captive, it's down to 4 parts. There's really no big advantage of using a dual spring especially on a duty gun.
 

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Isn't the goal of combat shooting to put as many rounds as necessary in the shortest amount of time to stop the attacker? The only difference between combat and competition is the targets don't shoot back. Go over to the sandbox right now and you'll be surprised how much competition gear is being used in combat.

For a combat gun, KISS. USP guide rod has 8 parts. Go with a standard spring while keeping it captive, it's down to 4 parts. There's really no big advantage of using a dual spring especially on a duty gun.
So why do you think they incorporated the dual spring design? Why did they carry it over to the USP series from the Mk23? Marketing gimmick, production simplicity, or actual advantage to the firearm?
 

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I think that it works. My wife's USP 9mm, even with its high bore axis, is much softer shooting my p2000, g17, and an assortment of other 9m.
 

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I think the only reason to run a dual spring is if you have to feed it a steady diet of +P ammo in 45 and +P and +P+ in 9mm. There's no such thing as +P for 40. If you were to feed a gun a steady diet of +P, you would want a heavier recoil spring so you don't beat the gun to death. But that would mean that the gun would be over sprung for standard loads.
 

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As for pros of the set up. The original Mk23 design used the dual spring because it's more effective in absorbing recoil forces even when firing the special Mk23's 45acp ammo that blows through ship bulkheads. This is because the 2nd spring comes into play to slow down the slide. The USP inherited the dual spring design originally because it's designed as a 40cal gun, probably to remove some of the "snap" in 40cal which is more sudden than 9 or 45. In a 9mm and standard 45acp, the dual spring is probably not needed. It's more complex and also more expensive. That's why you don't see it implemented. Apple to apple, I'd imagine dual-spring extends the gun's life compared to single spring design.
.45acp specialized ammo???

The only specialized ammo that I am aware that goes with the Mk23 is the hot (non-SAAMI spec) 185gr FMJ-TC which was thought that can tumble inside torso hits. But because of lack of improvement in terms of wound incapacitation, they abandoned the idea. I dont have any idea it can blast ship's bulkheads considering that even the hottest .45acp may never be as close as a moderate .44MAG loads.

As for dual-recoil set-up:

Thanks, my new recipe may be the right load for my USPf9 for defense which is on the hotter side: 115gr FMJ-Enc Hornady with 7.0gr 3N37 COL=1.140-in.
 

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Actually the specialized 45acp ammo for Mk23 exists based on the feedback of US Navy personnel. It has a separate NSN designating that ammo to be only used with Mk23.
 

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My .02, I find the USP under sprung, each new USP I pick up gets a new Wolf recoil spring that is at least 2lbs stiffer. My 9mm has a 14lbs and the .45 has a 16lbs, it just feels better in lockup, cycling/recoil and reliability.

Bill
 
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