Scaling down the 50y NRA Target

To scale down an 8" x 8" circle target used at 150 feet to be practiced on from 3 feet away, I used the concept of similar triangles used to find the reduced size of the target when viewed from a closer distance.

First, I set up a proportion to find the scaled size:

(Size at 3 feet) / (Size at 150 feet) = (Distance at 3 feet) / (Distance at 150 feet)

(Size at 3 feet) / 8 inches = 3 feet / 150 feet

Now, solve for the Size at 3 feet:

Size at 3 feet = (3 feet / 150 feet) * 8 inches

Size at 3 feet = (1/50) * 8 inches

Size at 3 feet = 0.16 inches

I scaled this down and it looks good to me in my garage. Has anyone tried anything else different?

Here is an article that speaks to this subject:
https://thecmp.org/making-dry-firing-targets/

Diameter is one thing. Theres probably a 'blur factor' that would require a bit of tweaking so it really looks the same...which would probably also vary with the lighting.

Scoring rings are easy. Add bullet diameter, scale, subtract bullet diameter.

And try not get freaked out when you see what you just created.

Here's the formula I use:
(full size target in inches / distance in inches) X (new distance in inches) = reduced target
Just remember to convert the distance to inches when calculating.
 Stan