Wednesday 24 June 2020


Back when I was active in the World of Tanks community, the idea that the D-25T gun could hit the broad side of a barn seemed bizarre and impossible to many. Documents suggesting otherwise elicited heated discussion, with many suggesting that this is anything from an outlier to a fabrication. Fortunately, these trials were commonly performed as a part of standard QA testing, and many similar results are available.

Firing at a range of 2000 meters. This tank used a D-25T gun with a sliding breech and old 10T-17 sight. At 2000 meters, all shells fall within a circle 130 cm in diameter. The best 50% of shots fall within a circle 72 cm in diameter. The point of aim is 10 cm off in the vertical and 100 cm off in the horizontal axis. Slightly worse than the previous result, but you can see that it was hardly a fluke.

Another D-25T with an old sight, this time with a screw breech, firing at 1000 meters. The point of aim is off the center of the impacts by 40 cm vertically and 73 cm horizontally. The dispersion is not given, but from the image it can be estimated as 26 and 59 cm respectively, slightly better than the original result.

This is a D-25T with a sliding breech and the new TSh-17 sight at 1000 meters. The data is given right on the page: 40 cm for the best 50% and 70 cm for 100%. 

Another gun and sight of the same type. This time the sights are much better set: the deviation is only 14 cm horizontally and 20 cm vertically. The grouping is about par for the course: 26 cm for 50% and 95 cm for 100%.

The same gun at 2000 meters. The deviation from the point of aim increased slightly to 24 cm in the horizontal and 18 cm in the vertical. The radius for the best 50% is 90 cm, for 100% is 129 cm. Slightly worse than the first gun in this post, but about the same as the gun in the previous post. 

Let's compare that with some other guns. 

The same gun on the IS-3 shows better results than on the IS-2: the best 50% land in a 33 cm circle, the rest in a 40 cm circle at 1000 meters. At 2000 meters, these numbers are 88 and 154 cm, which is actually slightly worse.

The ML-20S has the best 50% group landing in a 32 cm circle, and all shells in 96 cm at 1000 meters. The D-25 shoots noticeably better than this. 

The ZIS-S-53 gun on a T-44 tank gave the result of 45 cm for 50% and 95 cm for 100% before breaking in, and 36 and 54 cm respectively after. Better than the D-25, but not by much.

The 88 mm KwK 43 on the Tiger II gives a result of 36 and 48 cm (first group) and 43 and 67 cm (second group). This is about the same as most of the D-25T guns, with some showing better results. The result at 2000 meters is 62 and 93 cm, which is better than most D-25T guns, but still comparable. 

1 comment:

  1. Flawed theory about bad accuracy of D-25T gun is very common- as examply, I hear about bad accuracy of D-25T on youtube in Polish video serie about IS-2. BTW- in real accuracy important is not only dispersion, but also flatness of trajectory, but according my data, D-25T have 1130 meters of point blank shot for 3 meter tall target. In my opinion that's good enought in typical situation.