[Double Naught Spy]

Shooting bowling pins with pistols, right, and the distance is 25 yards. Is that also right?

Assuming you have a ricochet off a pin that takes off over the berm, the range of the round should be greatly reduced, should be. It should suffer some deformation, loss of rifling spin, and may even start its own spin that buzzes. These all upset the aerodyanmics, hence reducing risk compared to a round fired straight.

Down range ricochet threat to your neighbors is down range. Ricochets that are more lateral than down range will have lost a lot of energy as will have bouncebacks. So you are not likely to put holes in your neighbors to the left and right of the range even if a round manages to pop up and fall out of the sky onto their property.

Probably the most significant risk is the unencumbered unintentional shot over the backstop, not a ricochet. Once again, the danger is down range, not lateral.

To help offset the risk of putting holes in neighbors, you would do well to orient your range such that there are no homes, barns, buildings, etc., downrange in the direct line of fire and several degrees off in each direction from the line of fire. This should be for the estimated distance your ammo might go on an optimal day. I seem to recall artillary Lugers having a max range (on the sights) of 600 yards. After that, the threat of harm is greatly reduced (supposedly).

If you, yourself, can't shoot inside, you might do well to have your impact zone located in a structure such as an old barn where you still put in the same sort of backstop, but the sides and roof preclude any high velocity ricochets from taking off unencumbered.