Oh man....that is a lot of drop. For a round to drop that much it wold have to be at a further distance for sure.
Does it sound different...other than feel different?
At that distance the powder level in the rounds would have to be way off. should sound different... if it is the ammo and dropping 2" in 50'.
If the powder were that low in the round it would drop way more in 150 ft.
I would suggest trying different ammo see if it feels different. Ive shot a lot of white box and never had a problem. Maybe something else going on.
If you ever have to use a firearm, you don't get to pick the scenario!