Illustrated mostly with guns coming up for sale at Rock Island Auctions, most of them from the Brotherton Collection (thank you, Bear).
The 9mm Blowback MP
First, Walther tried scaling up the classic PP (Polizei Pistole) to the German 9 x 19mm service cartridge. This was called the MP (Militär Pistole) and had the problems you’d associate with making a 9mm blowback firearm. With the unlocked breech, the firearm needed a heavy slide and stiff spring to be safe (although it’s much safer to rely on bolt [slide] weight than spring tension). While you can see a touch of P.38 ancestry here, it’s mostly just a PP with thyroid issues.
Like an Uzi as much as like Browning’s original slide patent, this massive slide. How heavy does the slide have to be? Orion’s Hammer makes use of this equation from Chinn :
bolt mass in pounds = 1.09×10-5 * bullet mass in grains * bullet velocity in fps * (diameter of bolt face / diameter of bullet base)2
To make an approximate calculation of 1.7 lbs. which is a pretty heavy slide weight, mostly well forward. (Good for bullseye accuracy in rapid fire, unlikely to be popular as a service pistol). He uses a somewhat odd 9mm load (88 grain bullet at 1600 fps) but changing the load at the same chamber pressure should, ceteris paribus, give us the same bolt weight (because any changes in weight should produce a change in velocity).
So, a blowback 9mm worked — we think the owners of any of these rare birds can shoot them with perfect safety, Walther engineers could do math — but it wasn’t optimal. Time for a new gun.
The “Hammerless” MP and AP series
This early prototype is named “Walther Armee Pistole MP” and it’s fairly close to classical P.38 form. The departures include: lack of a slide arch at the front, slide reinforcements, and a “hammerless” (really, internal hammer) design. We don’t know why Walther went with the internal hammer. They had used an internal hammer decades earlier on some of their pocket pistols, like the single-action PP forerunner Model 8, and perhaps they thought the Army did not want an external hammer (the P.08 Luger was striker-fired, and the Army’s problem with it was primarily its cost — in Reichsmarks, machine time, and materials). There are some small and subtle differences from later P.38s, also, like the checkering pattern on the grips. This image also lets you see how the proto-P38 frame retained some of the features and aesthetics of the 9mm PP-based MP.
According to Rock Island, the pistol above is Serial Number ?? The following one is serial 044. It has taken several steps closer to the final P.38 in the shape of the slide and in some details such as the takedown latch, the bolt catch, and the grip checkering.
This firearm, serial number 09, we’ve already seen in an earlier post. It appears to be a cousin of #44 above, and is labeled Armee Pistole. The long barrel and stock/holster are original.
A “Sheet Metal” P.38? Or an Early Toolroom Prototype?
This weapon is hard to figure out. RIA describes it as a sheet metal P.38 prototype, but it has many very early features, and may be the original P.38 prototype or toolroom mule, in the white, with some parts like the slide built up from sheet or plate due to lack of forgings.
Note that the takedown latch, sight, and safety all resemble early designs, but the slide release resembles the later design. A fascinating one-off, whatever it is.
These weapons evolved into the P.38. First, though, they passed through the Heeres Pistol stage. This is a 1939 made HP for Sweden. It is for sale by Hallowell & Co. We’ll show you both left and right.
In most details, this resembles the later P.38. In comparison to the earlier guns, the HP has a smooth-sided slide, and most clearly visible, an exposed hammer. The grips have the same checkering pattern as some of the prototypes, but are made of a bakelite-like thermosetting.
Next we have a typical wartime P.38 (although it has an uncommon manufacturer code, 480) which is, again, for sale by Hallowell & Co. in Montana. And again, here are both left and right.
Changes are cosmetic and small, although the replacement of checkering with serrations on the takedown lever probably saved some manufacturing time. While the grooved grips that replaced the checkered ones are obvious, the much larger recess for accepting a lanyard snap is typical of the many small improvements in the wartime Walther.
The P.38 in turn evolved into the postwar P.1, which was basically a P.38 with an alloy frame. Due to loss of engineering documents, at least some parts of the P.1 were reverse engineered from production P.38s. The grips reverted to checkering. There are several versions of the P.1, and many variations of the postwar commercial P.38.
Walther also produced a modified, slightly shorter-barreled version as the P.4.
Then, finally, the P5 was the end of the line for Walther’s 1930s DA/SA tilting-locking-block design. The Walther P88 and subsequent service pistol designs used a modified Browning tipping barrel. The Walther style tipping block of course made a jump to Beretta in the M1951 and all its successors, including the M9.