I've helped support and maintain upwards of about 50 SW99's and a P99 for several years, the majority of which were issued guns. I carried one the issued SW99's (.40) and own a couple of them, a standard .40 and a compact 9mm.
During that time I had the opportunity to attend 3 armorer classes for the SW99/P99 platform and had a chance to see how they held up under various conditions. Most of the guns were only fired for familiarization and qualification over that time, but some number of them were fired quite a bit.
The well-used guns included one used as a loaner by a retired LE firearms instructor who teaches firearms classes, a fellow who has fired more than 50,000 rounds through a couple of standard 9mm & .40 S&W models and several thousand through a compact .40 model and some of the ones I used and own (in which the round count varied from several thousand rounds to just shy of 10,000 rounds).
During that time I've had to replace some parts for repair/correction purpose.
Just off the top of my head I can remember a couple of sear housing blocks because of broken ejectors (molded into the block itself). One after several thousand rounds (and it turned out to be the wrong caliber ejector/housing in the gun in the first place) and the other in a pistol which I was told had been used to be fire more than 50,000 .40 S&W rounds (sort of understandable for an ejector to require replacement with that many rounds fired
).
A cracked slide end cap ... a damaged rear sight and a couple of rear sight plungers (which suffered broken 'ears' from impacts) ... a couple of bent slide stop lever springs ... a couple of extractor springs and an extractor ... a trigger bar guide insert (wrong dimension original part).
I've also replaced various springs as part of normal maintenance.
The original .40 magazines had to be replaced with redesigned magazines. (S&W engineers helped develop info Walther used to have the magazine bodies and followers redesigned to resolve premature slide stop lever engagement.)
S&W also revised the barrels used in their .40 models to enhance unlocking/locking by incorporating a machined 'flat' into the bottom of the barrel at the rear, which was claimed to offer better clearance between the barrel and the top of the recoil spring. I've seen different production S&W .40 barrels in which the machined relief was either longer or shorter. I've also noticed minor revisions and changes in different production barrels in the way of chamber mouth dimensions, feedramp polishing and muzzle crowns. Sometimes the newer barrels resulted in improved feeding & functioning in some of the early guns, and in other instances early guns with the older barrels worked just fine.
I can remember being told of some other minor revisions and improvements which occurred along the way with the Walther manufactured parts, such as polishing of extractors, a change in the locking block and a change in a frame dimension (which resulted in a change in the sear housing block dimensions).
Overall I think the 99 series is a good design and makes a fine service grade pistol.
I think the sear housing block is a bit tricky. If the sear pin in the traditional double action housing block slips out during an armorer detailed strip (or during shipment of the housing block as a part
) it can be a bit tricky reinstalling the single action sear and its spring back in the block. Even armorers are told that the sear housing block should not be disassembled, although some instructions are included in the manual in case the sear pin slips out when the housing block is removed from the gun (or during shipment of the assembly ... did I mention that??
).
In order to replace the slide stop lever spring in the frame the locking block has to be removed. This requires using a ball peen hammer and a roll pin punch to remove and reinstall the roll pin (Not a simple spring pin, either). This takes some effort and care must be taken so the frame isn't damaged. The spring used in the SW99/990L guns is a bit stronger than the spring used in the Walther models, but it also has a more exposed 'hooked end' which can more easily be snagged and bent by the owner/user during cleaning if they are inattentive.
Now, although S&W has naturally shifted their attention to their own new polymer-framed model line (the M&P pistol series), they're still supporting the SW99/990L guns when it comes to parts and warranty service. (I'm sure it wouldn't surprise anyone to hear that they might be offering some sort of incentives for existing LE customers using the SW99/990L to consider transitioning to the new M&P, either.) They're still the licensed importer for the P99 series through their Walther America part of the company.
Now, Walther parts are a bit expensive. The sear housing block assembly is almost $100, compared to the M&P assembly which is less than $30 (and made of steel). The Walther trigger bar is more than $40 and the M&P is less than $13. The Walther magazine catch is not quite $40 and the M&P is not quite $3. The Walther recoil guide rod assembly is about $11 and has a plastic rod, while the M&P assembly is less than $7 and uses a stainless steel rod.
It can also sometimes require a bit of a wait for Walther to ship parts to S&W (Walther America) from Germany.
The S&W lifetime warranty certainly seemed attractive compared to the 1-year Walther warranty (especially when you considered S&W included the Walther frame and all the Walther parts under its warranty on the licensed SW99/990L models).
Now, I like my SW99's. I think they're fine guns. I think the Walther P99's are fine guns. I think the 99 design offers some nice refinements in the evolution of the polymer-framed pistol.
I like the decocker. I like the striker return spring. I like the front frame rails of the compact being incorporated into the locking block. I like being able to remove the striker assembly for cleaning without having to remove the extractor & safety plunger (and vice versa). I like the replaceable grip backstraps.
However, as with the Glock platform, I personally think the 99 platform is at its optimal when chambered in 9mm. Just my personal thought.
Yes, it seems to take anywhere from a few hundred to several hundred rounds for the average 99 trigger to settle in. It's seemed to vary from one gun to the next in my experience.
My SW99 9mm compact is a great little pistol and it's one of my favorite for range training. It came as somewhat of a surprise to me when I finally realized that I'm consistently able to wring some better practical accuracy out of the little SW99 compact than my 3913.
Okay. That's just my thoughts and experiences.
I don't make blanket recommendations when it comes to other folks buying guns, though.