Kedr PP-91 (9 x 18 mm Makarov)
 

Two different versions of the Tyrex exist: one is a semi-auto model and the other is both semi-auto and full-auto. However, even the semi-auto model can usually be made to fire in full-auto mode by pushing the fire select lever about midway between the position marked "F" and the unmarked position. All tests on the Tyrex were conducted in semi-auto mode.

To operate the Tyrex, first engage the safety and then load a CO2 cartridge in the grip. Make sure the CO2 cylinder is properly seated before tightening the piercing screw. The piercing pin is fairly short, so it is best to use CO2 cylinders that do not have depressions in their tips (Crosman cylinders work well). Loading BBs into the Tyrex magazine is a labor intensive process. BBs are loaded in the magazine one-at-a-time by pushing down on the top of the magazine and then pushing each BB through the loading gate. (Note: the end of the magazine follower has a captive ball that looks like a BB. Do not attempt to remove this.) The magazine will hold a maximum of 25 BBs. Push the magazine into the gun and then pull back on the cocking handle. Move the safety lever to the firing position (labeled "F") and the gun is now ready to fire. The trigger has a very heavy pull (greater than 12 pounds) but breaks cleanly. The Tyrex can be fired like a pistol or the stock can be extended and used like a carbine. When the stock is extended, the rear sight changes from an aperture to a notch. Unfortunately, the short stock places the shooter's eye too close to the rear sight to make the notch sight useful. The blowback action of the Tyrex automatically recocks the gun after each shot giving the gun a kick similar to a .22 cal rim fire pistol. Since the blowback action uses some CO2 during each shot, the CO2 cylinder cools down rapidly. When the CO2 cylinder is nearly exhausted (or very cold), the gun will often go full-auto. On occasion, the last BB in the magazine will not be properly loaded and will fall out of the magazine well when the magazine is removed. The Tyrex gets about 85 good shots from a CO2 cylinder, which is very good for a blow-back design. Make sure the CO2 cylinder is completely empty before attempting to remove it. Otherwise, the cylinder can shoot out the bottom of the grip under considerable force.

The performance of the Tyrex is only fair, especially considering its very high price. While it has a high fun factor and is very realistic in both appearance and operation, it will probably be more interesting to collectors than to shooters.

ZMZ Website for the PPA-K Tyrex air pistol

Performance: Measurements were made on 12/17/10 at a temperature of 69 ºF and 4980' elevation. A ten shot string was fired from a bench rest at 15' using RWS Match Grade BBs (5.4 gr) and a fresh CO2 cartridge. The highest velocity measured was 321 fps, the lowest was 307 fps (average of the 10-shot string was 313 fps, s = 4.0). A wide variety of BBs were tested for accuracy with this gun. The results are outlined below. Click here for a description of the measurement methods.

6-shot group	RWS Match Grade BBs (5.4 gr). A six shot string shot with the aperture sight fired from a rest at 15' grouped at 1.80". This specimen of the Tyrex shot about 2.5" below and 0.50" to the right of the point of aim at 15' with RWS Match Grade BBs. Click the thumbnail to see a larger image.
5-shot groups	The following BBs were tested with the Tyrex PPA-K-01: RWS Match (5.4 gr), Daisy Avanti (5.5 gr), Crossman Copperhead (5.1 gr), and Daisy Precision Max (5.3 gr). The best group was produced by the RWS Match Grade BBs (1.42" c-t-c). All images shown represent 5-shot groups fired with the aperture sight from a rest at 15'.

Schematic diagrams for the Tyrex PPA-K.