I recently picked up a MAR177 to practice with during the off-season. I wanted some targets to mimic the SR-1 target at 12 feet but I could not find a commercial target that would be the right size, so I made one.
The math isn’t as complicated as it seems. Take the distance you want and divide by the distance of the target you are reducing. In this case 12/300 (feet) which is .04 then multiply that by the size of the target you are trying to reduce.
The black of a SR-1 target is around 6.5 which reduces to about .25
The formula looks something like this.
X = the distance you are reducing the target for.
Y = the distance the target you are reducing is designed for.
Z = size of target you are reducing.
Here’s the “Worksheet” I made with several 12 feet targets Download Here