Hawkmoon's impact is 81 without any barrel upgrades. Aggressive Ballistics might possibly push its impact very close to Timur's. Also, note that impact is not directly proportional to damage. It's a linear relationship. All guns have a base damage and Impact adds damage on top of that. It's why you don't see Shadow Price hitting for 20x more per shot than AE. So the 13 point impact difference between Hawkmoon vs Thorn and Hawkmoon vs Timurs will not give the same differences in damage numbers. Armor piercing round's original function is to hit two enemies at once. The wall piercing ability on snipers that has recently been popularised is simply a very convenient side effect for snipers. As for your varying crit damage, different enemies actually have different crit multipliers.