The M-32 Personal Defense Weapon looks a bit like a hybrid of of two famous early handguns. From the grip to the magazine located forward of the trigger guard, it appears to be a C-96 Mauser. However, the barrel assembly thicker with a large cylinder underneath, appearing more like the business end of a Colt 1911. A forward folding grip is located under the barrel to assist with holding the weapon, and non-moving top part of the receiver can accept a wide variety of scopes.
Its internal workings are quite different however - as its both gas operated, and gas controlled. Gas from the moving projectile is channels into a chamber beneath the barrel and goes in two directions. Forwards moves a small counterweight to balance the backwards recoil of the weapon. Backwards serves to act on a locking mechanism that controls when the bolt recoils. (Like the C-96, there is a separate bolt mechanism, rather than a moving slide as seen on other handguns.) In theory the weapon self adjusts to the power of the round fired so it can fire faster with low powered rounds (which need less time for pressure to dissipate before moving the mechanism) or slower with powerful ones. However, it wasn't uncommon for the two processes to become synced, and thus have the gun recoil forwards, then the slide unlock and go backwards. Many users would just accept normal recoil and remove the forward piston.
The weapon fires from a closed bolt, in both semi-automatic and full automatic modes. Although the barrel is fairly thick - closer to the "bull-barrel" designs of Colts meant for target shooting than the thin one of C-96s, this does mean it can overheat rapidly. However, unlike most early machine pistols that became quite hard to control when not used for single shots, this one limits the rate of fire, and has both he weight and forward grip necessary to make it quite controllable.
Early M-32s were issued with both ten round and twenty-five round clips. However, the former lied flush with the bottom of the magazine well, and could be quite difficult to remove if stuck. This usually required locking the slide back, and then pushing a long object through to push the magazine out, or gluing a coin to the bottom to give a better finger hold. After-market, and soon standard issue - eleven round magazines provided more area to grip, and a slight increase in capacity, while still nominally fitting in the holster. Of course, using a sling and the longer magazines solved the problem as well.
Despite the mechanical oddities and initial clip jamming, the M-32 was - and continues to be - a very popular weapon. It is both accurate in single shot, while retaining a controllable 400 round per minute full automatic. Since the clip is not in the grip, the size and shape can be modified to accommodate any size of hand. Furthermore, the 6mm steel core ammunition was appreciated for its striking power and as conventional cased ammo - was somewhat more reliable than either case-less or electromagnetic weapons.
M-32s were quite popular in the Zone, though their ammunition was somewhat rare. There had not been a large civilian market for the weapon before the Event - meaning that replenishment required finding an un-looted military wreck or raiding a potentially dangerous base.