Ballistic calculators and the need for them emerged during WW2. The need for a solution for ranging the targets was so critical that they began developing the solution at the telescope. That is only part of the solution. You need to consider other features, such as the ballistic performance of your ammunition and the shooters’ training.

At that time, range-finding reticles were not yet available. Instead of military reticles, they used hunting reticles. Ranging was primarily done through estimation, using a range-finding binocular or a sniper card. A range-finding binocular works similarly to a range-finding scope, with graduations allowing distance calculation or analysis based on the target’s average size. The sniper card involved knowing the distances of certain terrain features and using that information to determine the target range. Estimating distance played a significant role in German sniper training and was a skill acquired through hunting. The Russian snipers mainly used reticles like the “German #1,” initially using a copy of the 4X German scope and later using their 3.5X scope. The UK and Commonwealth forces used a “T-post” reticle type with 3.5 magnification.

It appears that the US Army used the “fine cross” and scope with magnifications between 2.2 x and 2.5 x, while the USMC used the same reticle but with 8 x and 5 x magnification. Both used full metal jacket flat base spitzer bullets, resulting in a ballistic coefficient of around 0.35–0.38 for the 7.62/30.06 and 0.46–0.47 for the .303. Tests were conducted simultaneously on WWII battle rifles from the US, UK, Germany, and Russia, equipped with reproduction scopes and modern FMJ-BT bullets. However, it was found that none of the stadia on the scopes could be used to estimate the range.

With those types of scopes and the ammunition of the time, the most practical method would be to use the concept of maximum point-blank range. Essentially, this is the range at which you know your trajectory will be within a certain number of inches/mm over your aiming point. Therefore, you can shoot up to 200–250 meters without precise range, which won’t matter much. The Germans used the “German 4” without the fine crosshair and the “German 1”, and they used a spitzer boat tail BC around 0.5 and a dedicated sniper bullet with a BC of 0.59–0.6. The distance between the two horizontal bars is 70 cm (on the sniper scopes) and 140 cm (ZF 41) at 100 meters, so it can be used to estimate the range.

The ZF 41 sniper scope has a magnification of 1.5X, making it more of a combat optic than a traditional sniper scope. It provides a more realistic chance of hitting targets at 200 and 300 meters than iron sights. Despite its intended use as a stop-gap sniper scope, it was effective. Additionally, the Japanese had a 2.5X calibrated scope, which could be used to estimate the range for the 6.5.