Well, since a few weeks I have a rather unique handgun. And since it is as good as I imagined it, I want to share some knowledge about it.
The gun is the Steyr GB, a 9mm handgun, large DA/SA (think similar in size to a Beretta 92) with an eighteen-shot, double-column magazine – and it is gas delayed blowback. Unlike the better known H&K P7 there is a collar around the front part of the barrel about 1/3 the way. The barrel bushing is long and sits around this collar. The GB uses some of the expanding powder gases from a fired round to form a counter pressure that delayes the opening of the slide until the bullet exits the barrel, allowing the gases to escape. The gases used to lock the slide come from two holes drilled at the midpoint of the barrel, and vented into a chamber sealed by the barrel bushing. The system is simpler and stronger, as it does not have moving parts (like the piston in the P7). Further the muzzle velocity is not reduced and the hotter the cartridge, the longer the lock will last, until the chamber pressure has decreased to a point, where the cycling of the slide is safe. The Austrian manufacturer at the time tested the gun with sub-machine gun ammunition.
The gun itself is made of carbon steel, with a fixed polygonal chrome-lined barrel (~5 inch), that is solidly attached to the frame (8 inch long), it's 5.5 inch in height and has a width of 1.25 inch at the grip and 1.0 inch at the slide, weighing about ~35 ounces unloaded with mag. The frame is made from two halves, welded together. For easier manufacturing, the frame does not contain a trigger guard. The metal trigger guard is pinned in place once the frame has been welded. The front of the trigger guard is checkered, the trigger has a rounded surface area. A black epoxy crinkled finish with rounded edges (“snag proof”) is standard. While some models had sheet-steel grips, most came with checkered black plastic grips. It can be field stripped without the need of tools. Field stripped gun is shown in the pictures below. To field strip, simply reduce the tension on the recoil spring (a specific lever on the right side of the gun) and twist the barrel bushing for about 30 degree. See as well the image of the business end of the gun without slide.
Steyr’s development finished in 1980 and market introduction was in 1981. There is a sad story associated with the first importer, who copied the design – neglecting the precision needed for such a principle – and hence produced a badly functioning gun. This can be seen as the cause of a bad reputation for the original Steyr, which was later brought to market by another distributer.
In terms of controls, the GB is a DA/SA, with a decocker, which lowers the spurred hammer (last version) while blocking the movement such that the firing pin could be touched and leaves it ready to fire double action again. The decocker is spring-loaded, jumping back into position after use. A 3-dot sight system, non-adjustable, that was luminous, ensures fast target acquisition. The slidelock lever is comfortable to use, big enough to work with, but not standing out or with sharp edges. When the mag is empty the slide locks back. The mag release is on the side of the trigger guard (European versions had the mag release initially on the heel). The steel-mags shoot out similar like in the 3rd generation S&W handguns. Mag loading is similar to sub-machine gun mags, i.e. the feed lips are as wide as the cartridge. There is no other safety integrated into the gun.
Other versions of the gun do exist. Steyr made some bushings that had compensators built in, trying to appeal to the IPSC crowd. The gas-brake would lend itself to other cartridges such as the 40 S&W. There were 3-shot burst capable prototypes and testing towards sub-machine gun performance. 30 round mags were made as well. Some first guns had unreliable feeding, a solution could be found by polishing the feeding ramp, however my version does not show any of that. Feeding from hollow points to round nose anything was taken. Being a mix of mid and last version, the version I have has a spurred hammer as well as an improved hammer spring, but a square trigger guard. The trigger pull on mine is crisp in SA and smooth in DA. Despite the late version hammer and mid version trigger-guard, according to the research I have a mid-production version, indicated by my serial number P-xxxxx. The mid-production has the importer's mark "Gun South, Inc., Trussv. Al." stamped on the upper portion of the slide.
I've shot the gun on the range and was quite satisfied with the result. It shoots about an inch to the left for me (I guess my trigger pull is not perfect on), but free hand groups with 1shot/second are ~1 inch from ~7 meter distance. I should do a more accurate test from a rest and post results. The gun is balanced in my hands and due to it's own weight and the reduced mass of only the slide coming back it is very low recoil. Almost like being glued to the target with a string. And 19 rounds without rest is nice (and was novel in 1981).
I can rest assured, that there will not be a holster for this gun. So if I so desire, it will be either a generic one, or a custom made one. Also the grips are easily to take off, hence maybe this could be a project for me to finally attempt my own wooden grips. All in all, I can only recommend the gun. Would you happen to stumble over it, don't hesitate to take the original Steyr. It's a shooter (accurate and cheap ammo) and an historically interesting firearm as well.