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How many rounds should I go between spring changes, for both mags and mainspring/recoil spring, on a USP9f LEM? Does the little captured recoil spring ever need to be changed? Do you generally change the main and recoil springs at the same time? What about the other/smaller springs?

In my experience it's obvious when a spring is past its life because you start to get malfunctions. I assume once you hit that point the excess slide velocity is damaging to the frame, and obviously you changing springs to avoid the malfunctions to begin with. But on a pistol with unknown round count, how do you know when to change the springs?

Thanks guys!
 

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HK recommends the outer recoil spring be replaced at 10,000 rounds. You only replace the inner if it breaks, which I've never heard of it happening. I have over 12K on mine (45 ACP Compact) and it is still as good as it's stable mate with less than 1K through it. Mag springs, no telling. Replace if and when they fail to lock the slide back.
Hammer spring, does not ever need to be replaced.
I would not replace anything unless there was a sign that something was wrong, such as slide not locking back (mag spring) or the cases being thrown 10 feet from the pistol and excessive recoil. My 9SD only throws the case about two feet on full power loads and mild loads often just dribble out, but I've never had a malfunction. Honestly, IMO you will never need to replace the recoil spring on a 9mm USP full size.
 

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HK recommends the outer recoil spring be replaced at 10,000 rounds. You only replace the inner if it breaks, which I've never heard of it happening. I have over 12K on mine (45 ACP Compact) and it is still as good ...
But the compacts have a single flat spring.

An engineering type with a lot of experience regarding spring dynamics told me that the flat springs have more "service life", durability, whatever term you care to use, than coil springs made from round stock.

Dunno how accurate that is, however I know of a couple of Glocks with 20K+ rounds and the original recoil spring assembly that show no signs of a weakened spring, as you noted.

An interesting question, this... ARE the flat springs longer lasting than "regular" round stock springs? Both HK45 versions use a single flat captive recoil spring, with a claimed service life of 20K rounds. Todd Green put 50K full patch ball rounds though the big one, and IIRC did not change the recoil spring assembly. Not sure about the spring being changed, but the round count was verified.

I shoot my HK45C quite a bit, and still am shy of 5K rounds through it. So I'm not too worried...:wink:

.
 

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Personally, I would do scheduled maintenance on my pistol a few thousand rounds before the factory recommendation, just like I do scheduled maintenance on my car a few thousand miles before the factory recommendation.

I stopped listening to factory recommended schedules aroud the time that BMW told me the transmission fluid lasts a lifetime, and non-synthetic oil should be changed every 15k miles.

When it comes to maintenance, I do it before the factory recommendation. No harm can come from this.
 

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I have a parts kit, Full recoil spring setup so I can drop it in, and some odds and ends. It is a good Idea to have 2 changes of springs and wear parts for every gun you have. Expensive as f*ck, but you will never be found wanting or waiting. Plus if zombies or terminators take over, I have to keep my HK's in the fight, because I will be damned if I am going to throw them away.
 

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Personally, I would do scheduled maintenance on my pistol a few thousand rounds before the factory recommendation, just like I do scheduled maintenance on my car a few thousand miles before the factory recommendation.

I stopped listening to factory recommended schedules aroud the time that BMW told me the transmission fluid lasts a lifetime, and non-synthetic oil should be changed every 15k miles.

When it comes to maintenance, I do it before the factory recommendation. No harm can come from this.
Of topic here but I do have two BWM that are over 100K miles w/o any problems by just simply followed factory recommendation. No transmission fluide change yet and 15k or more depending on how I drive that particular year, only change once a year:). If I change it more often it will probably last longer but I don't feel like ride the same car forever.....

Back to the topic....Folks, just follow factory recommendation. Their recommendation is based on a lot of reliability qualification testings. It costs them money and reputation if their product came back for prepair prematurely.
 

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I called and talked to H&K about my P2000 LEM with 20k rounds downrange.
They recommended changing the trigger rebound spring, the flat spring and the recoil spring assembly.
 
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