Beretta-here are some more answers for you-
While I'm unaware of any real problems with any of the P5s (P5Cs are another issue-to be discussed later!), there have been several incrimental changes made subsequent to their 1978 initial issue (Dieter Marschall covers these in detail in his excellent, and inexpensive book "Walther Pistols Models 1 Through P99"-you can get it from Earl's Repair at
www.carlwalther.com). The magazine release has gone through at least 3 improvements, and has been mentioned earlier, the trigger overtravel stop from Dec 1990 on has been moved from the back of the trigger to the receiver frame (and made adjustable). In an ideal world, I think that the best "find" would be a new-in-box post October 1992 P5, which would seem to have incorporated all incrimental improvements-such would be from serial #100730 on (the date code on the right side of the receiver would be KC, or with some later letter following the "K", such as KD or KE, etc. The German proof date coding system assigns the letter K to signify 9 (as in 199_), and the letter A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7, J=8, and K=9; so I suppose that it's possible to find a 2000 or later P5 (although I personally haven't seen any); such would be date coded "A_".
And there are some variations-for example, while my P5 is a KC proof date, and a post-101 serial number, it doesn't have the new hammer that Dieter has specified-Walther is kind of like Colt it seems, in that changes are gradually phased into the ongoing production stream. I've also seen a P5 with the larger, more billboardish-style of banner/manufacturer's markings (like those on the P5C) on the left side of the slide.
I am unaware of any locking block issues with the P5 line in its entirety. Walther changed locking block fabrication in 1972 for the P38/P1 from a casting to a forging, so I assume that all P5s have forged locking blocks. An earlier surplus P1 that I had did have suffer a cracked locking block after I'd had it for awhile, but to the best of my recollection it was one of the earlier cast pieces, and although the pistol was in excellent shape when I got it, it was a surplus Bundeswehr/Polizi piece-I have no idea how much it was shot, or what was shot in it prior to my possession. The upshot is, I'm unaware of any locking block issues within the P5 line-and the good news is, is that if the locking block ever does fail, it's easy enough to replace and fit, as opposed to the cam piece on many competing designs, where you for all practical purposes would have to get a replacement receiver.
Accuracy and shootability of the P5s are excellent. Be prepared for a slight "hitch" right before trigger let-off, as the trigger mechanism is used to physically raise the firing pin into position so that it can be struck by the hammer. Point of impact can be adjusted for windage within the adjustable rear sight; for height Earl's Repair has several rear sight heights available if you need to address this. Earl's stocks all necessary parts that I'm aware of-he's not cheap, but he is very knowledgeable and helpful, and is worth his due as he has taken the time to build up his business and knowledge for a relatively small marketing niche. Unless you are buying a NIB pistol, I would immediately replace your recoil springs and magazine springs, as they can take a set and weaken over time-and weakened springs can allow frame battering to occur (regarding the recoil springs) and jams/malfunctions to occur (regarding the magazine springs). Quality replacement springs can be found at Wolff Gunsprings (
www.gunsprings.com). Frankly, even if the pistol is NIB, I would probably replace these springs; I have been unimpressed with Walther magazine springs in particular (and another thing to check is that the magazine springs are properly installed/oriented with the magazine follower lying properly atop the spring).
Things to be aware of: Grips-The plastic that Walther uses is crap-although they are attractive and well shaped. I have found through painful (and expensive!) experience that this is the case with P1/P38, P5, P5C, and P88. They are inordinately susceptible to cracking and crystallizing, which tends to occur at or in the vicinity of the grip screws. They are also easily marred by a lot of cleaning/lubricating solvents. I've discussed this at length with Earl Sheehan of Earl's; the short version is that many US cleansers/solvents are harsher than what the Germans use-Earl specifically recommends using Kleenbore's Formula Three CLP for cleaning and lubing, as it 1) does the job, and 2) is gentle enough (I also haven't encountered any problems with FP-10 as a CLP, and TW-25B grease, but I tend to err on the side of caution and generally stick with Formula Three for the most part). I ALSO had this problem even more significantly with a P5C, where there is a plastic grip filler piece incorporated into the grip backstrap, sandwiched by the grip plates-this filler piece retains the hammer strut, and provides the necessary leverage for the hammer strut and its spring to work. The one on mine crystallized, cracked, and broke-rendering the gun unfireable. I was NOT a happy camper, to say the least-again, the gun concerned was used, so I have not the foggiest as to how it was previously cleaned and maintained. Fortunately, Earl's had the part, and my gunsmith was easily able to install it (with some guidance from Earl!). Incidentally, this problem is limited to the P5C; on the P5, the hammer strut/spring is affixed to the aluminum frame itself. But-for grips, on the P5, Hogue actually has a set of their rubber grips for the P5-and they've updated it a couple of times as well to reflect the incrimental changes made to the P5; they have an excellent feel, and are inexpensive. To further (and more expensively) dress up the grips, Nill-Grips is probably the way to go-MacTec is their US vendor, and Ken Lunde has some beautiful pictures on the sigforum site as to how they look.
For carry, there are some excellent holsters out there for the P5-I've personally used and recommend Kramer (particularly their #3 IWB model), Blade-Tech, and The Wilderness (they make a very functional belt slide holster that the call the Zip-Slide). If you can find 'em (and if they can make one for the P5), I'd also recommend Orca Custom; I've just picked up one of their nylon IWB holsters for my Beretta 92D, and am very impressed with it-and they're inexpensive too. Earl's Repair is another good source for Walther-specific holsters.
For carry ammunition, I've chosen to remain with a standard-pressure load for my P5-Federal's Classic Hollowpoint, code #9BP. This round has a excellent reputation for both accuracy and stopping power.
Well, this has been a fairly long answer to your questions-I hope you find it useful. Best of luck in your search-let us know what you get-and feel free to ask away for any questions that you have. While this isn't necessarily the busiest board, I've found it to be a very friendly and knowledgeable one.
Incidentally, if you (or anyone else is interested, I recently traded in my P5C at Bullseye Shooters Supply in Tacoma, WA, where they have it for sale for either $699 or $799.00-I forget which-it's in excellent shape, with some very minor freckling on the slide (which was there when I got it!)-and its got new grips and a new filler/hammer strut retention piece!
Best, Jon