Dec 21, 2010

My Waltherex PK380

__________________________________________ (r4, Dec 29)
My PK380 disappoints. If you buy one, you might need to send it for service.
If you have small tools and magnified light, you can do much yourself, but
check the warranty disclaimers. Avoid guns with AK(2009) on the slide.

The P22 and PK380 are not good for the "Walther"(Umarex?) reputation.
Umarex owns Walther, and builds the PK mainly at Koln Germany(near Belgium)
though the housing states "Carl Walther Ulm/[Danube]"(south-central).

The PK380 is partly based on the excellent Walther p99, but many folks
have issues with 9x19, which are much stronger and difficult to deal with.
A 380 (with a 3"+ barrel) is a compromise for routine home/car defense.

This gun is sold for personal defense, such as at policemag.com :
"...PK380 ...all of the features needed for personal defense situations,"
said Tom Kelly, Smith & Wesson VP. "...upgrade of the same design[P22]
in a self-defense appropriate caliber. The PK380 fully answers these
requests while delivering a fit and finish that firearms enthusiasts
have come to expect from Walther firearms." [?]

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In some, maybe just 2009, guns, the hammer safety spool can break in half
suddenly. .A close-up of a fractured spool shows typical ductile/brittle
fracture patterns starting from a sharp internal corner where it intersects
the outer diameter, but at the side opposite from the hammer.
Walther has not announced a change, but if they're awake, they have
improved the spool production process.

There are avoidable stress concentrations during MIM sintered-part cooling,
but mostly at recoil impact. There are reports of dark coloration on fractured
surfaces, likely from the uneven globular structure of fractured sintered
steel, which includes some binder residue in the voids.

I think that normal recoil impact is the major risk for the safety spool.
A spool might break at dry-fire, but I think those are only the last straw.
To help confirm this, I dry-fired in safe-mode over 300 times before firing
another 100 rounds. .There are 350 rounds through the gun, 300+ dry-fires,
and a few hundred dry cycles with snap caps.

After polishing, under strong light/magnification, there are no visible flaws.
I've seen pics of four busted spools, and all four indicate that stress at the
f-p slot, opposite from where the hammer is slammed by the spool in recoil, is
the source of fracture. (I checked contact of my hammer and spool, and found
that there was a strong concentration at the lower left corner of the spool.
I was able to modify the hammer at that point to greatly reduce that stress.)

I see a similar wear imbalance in the same location in video of the newer
signal-gas 'PK380'version. The nominal drawing dimensions seem to be off,
or there could be a stackup bias in production.

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Another avoidable issue: The internal trigger locking pin can jam up the
works if it's in the "S" position while trying to rack the slide, or while
forcing back the hammer, or maybe when forcing the trigger. .Tension during
a real threat can easily lead to this if the trigger was locked (as intended).

The trigger tip on mine moved about 3/4" in DA from 'grab' to 'fire'.
The first half of travel was under 5 pounds, then rising to 10 at break.
If your DA trigger is not easy in the first half, the trigger lock is
likely in the 'S' position, and if you pull the trigger over 20 pounds,
or if you force the slide or hammer back, the polymer trigger claw can
slip off the lock-pin and get jammed on it. (reports, testing, inspection)

It should be fairly obvious from resistance if the trigger is locked, but
some folks report this problem. Racking in the locked mode is not very
difficult. .If this happens, try just bumping the slide forward. Forcing
the hammer too far is difficult, but clearing requires removing the slide.
I added a "shelf" groove to the lock-pin so that the trigger, slide, or hammer
would start to move, but suddenly stop to make it clear if the lock is engaged,
and to avoid slipping of the polymer claw at the lock-pin.
.

Note to Umarex-Wather-SW

If you want to engage in pre-litigation discovery, please send a preliminary
cause brief to ebrownee@gmail.com, and include preliminary requests for
admissions. All theories should be included, with citations, since I've
covered the usual statutes and cases, state and federal.

If you manage to show a claim with real merit, I would not fight that, and
Google would not be a legal obstacle. Then I could provide you with my
preliminary brief on counterclaims, and a preliminary requests for admissions.
[RPost is good, but I won't use my RPost account yet.]

If my PK fails, with substantial harm (beyond warranty disclaimers) and due to
neglect of known problems, then strict liability would be one pillar of the case.