### (29 March 2014)

During World War I, the Paris Gun bombarded Paris, with the shells falling in the locations shown in the map below:

If we assume that all these shell “splash” locations represent 95% of all rounds fired, we can then estimate CEP and accuracy from it, particularly since we have another WWI era map of Paris with an attached scale handy below:

Combining the two maps results in the following:

We get the above map.

Drawing a circle on the combined map that encompasses virtually all of the bombardment locations gives us a circle 6,300 yards in diameter (5,760m), or a radius of 2,880 meters.

Assuming this is the R95 (95% of all shells fall within this radius) for the Paris Gun, we can then calculate CEP by dividing by 2.1; which means that Paris Gun accuracy is about:

R95: 2,880m
CEP: 1,370m

Using the Nuclear Exchange Calculations (HERE), we can then calculate the number of rounds needed to destroy a point target with the Paris Gun.

If we assumed that we had to get the shell within 15 meters of the target to destroy it and that the shells had a 80% reliability rate, the following probabilities of a kill would shake out:

 PKill % Shells Fired to Achieve Goal 10% 1,600~ 25% 4,330~ 50% 10,450~ 75% 20,900~ 90% 34,650~ 95% 45,100~