A bit of a pet peve of mine also. I changesd philosophy years ago and try for a clean match. I shoot pretty slow too.
The general rule of calling misses sounds good, but we are all human.
Devils-advocate hat on:
So if you don't see the bullet strike the berm, or other non-target entity, how does one really know it was not a hit. OR, in other words If I don't SEE it hit the target, and I don't HEAR it hit the target, again, how do I know (for sure) it didn't hit the target, unless I see it hit something else(?)
Obvious obstacles abound. First there is the "fog" of black, and the resounding boom to mask the targets visually and audibly. Folks usually combine their senses to make a call.
I have had several called "miss" each year. I shoot .44's with 25 gr FFF in my handguns and 200gr MAV and 33 gr in 44-40 rifle.
Targets hit near a hanger may not sound or look like a hit (thus, ocasionally a miss is mistakenly called). Multiple "tapping" a target causes some target movement that can disguise a hit as well. Had a bank of swingers that we double sweeped with both handguns. The second shot on target 1 appeared to hit dirt 5+ ft rt of the target as a miss, but in reality, the ball glanced off the target without a sound audible (over the boom) and due to the angle of impact and movement of the target, the ball flattened and spun off. Had a similar event happen with the 44-40 rifle at our 2-day match, costing the clean match.
BP savy stage designers can help reduce some of these problems by spreading out targets a bit and keeping them back at the maximum recommended ranges, reducing double taps, etc, too.
If you shoot any C&B and/or BP cartridge, you have to prepared for getting the erroneous called miss.
You'll just have to be "good" knowing how you really performed.
The situation has gotten much better now that more BP shooters exist. As these "converts" experience shooting BP, they understand better how to spot it.
Regards,
Slim