If he didn’t need a range finder for the distance he was shooting then how would he have missed? My point is let’s say the deer was at 26 and his range finder errantly read 18. Wouldn’t he still hit the deer in the vitals based on what you just said about a single pin from 0-30 for most setups?
Im in the same boat for the most part but I like a cheap range finder to figure out my 20 yard radius at the beginning of my hunt. If I need a really good rangefinder to gather enough light at the end of the night to figure out how far the deer is I should definitely not be taking that shot.
Range target known at 10 yards: his rangefinder said 20.
Click button again, without moving: 23
Click button again, without moving: 12
Change batteries, rinse repeat at varied distances.
It wasn't off 10% every time. It was off random amounts, sometimes signifcant amounts, and sometimes close.
HE'S the problem, not the rangefinder. Why - because a monkey could have figured this out in ten seconds on the range, but he never did. He just had it in his pack for hunting. Never brought it to the range.
He's a 26" draw. Shooting a 450 grain arrow. My advice to him is to never shoot past 25 based on bow capabilities, and 20 based on his shooting ability. If he had a single pin set at 18 yards, and he ranged a deer at 30 (and it was standing at 10), according to my advice, he wouldn't shoot it. In your hypothetical, he'd have to be shooting a minimum of 250FPS (he's not), and he wouldn't miss the deer.
I didn't say I was using the rangefinder to gather enough light to SHOOT a deer in low light conditions. I said I was using it specifically to SPOT deer on hard contrast horizons at low light, to prepare. How could I shoot the deer with my rangefinder in my eye?