I shot two deer last season with the 250 gr SST-ML with 100gr of 777 pellets.
Irecovered both deer within 100 yards, with good lung shots made, but there wasvirtually noblood trail to follow.
I was very fortunate to find the buck, we did alast ditch wide circle and ended finding him.

So I shouldn't say they don't put deer down, but rather that they aren't made for hunters with poor tracking skills....