Factorio Forums

try the following:
1. add force = "not-same" to the area action of "explosive-cannon-projectile" (safety first^^)
2. the vanilla min_range of "explosive-cannon-shell" is 5, so we'll set our projectile_creation_distance of the "tank-cannon" to 6
OR: 2. the vanilla projectile_creation_distance of the tank-cannon is 1.6 so we'll set our min_range of "explosive-cannon-shell" to 1.3
3. Launch the game and set up your tank with explosive cannon shells
4. aim very close to the center of the vehicle and shoot a few times (might be fiddly to find the exact spot)
Result: If you aim too closely, the min_range will get ignored and you shoot yourself

another thing in noticed is that the min_range is calculated from the (elevated) position of the gun, which does not reflect the real world because you can shoot very closely southern of your vehicle but the perceived min_range northern of the vehicle is much larger

Unless we encounter a problem like this in the base game with base game features, we aren't going to look into fixing it

This is even "less" as an issue because the various ranges, speeds and delays mean that if you try shooting at biters very close to your tank, you will very often end up damaging yourself too.
But this seems to be a design feature : use flamethrower or regular canon shells if you want to keep it safe !