Sorry I guess I wasn't clear when I said "map them".
I didn't mean take several reads & average them, I meant you need to take several readings at different points
& then average those readings so you get an idea of where each position rates for noise. Usually the meters have some kind of attachment so you can put them at different points in front of, to the sides of & behind the gun safely. Then you actually draw a "map" of the sound patttern. If you don't do this you'll never know "how loud" it is because the percieved loudness will vary with location & distance.
You should end up with something like this, distance from center is "loudness" & directioin is from the source to the meter's mic. Yours won't be this complex as you're just measuring one parameter, overall noise.
Allan Quatermain: “Automatic rifles. Who in God's name has automatic rifles”?
Elderly Hunter: “That's dashed unsporting. Probably Belgium.”