Here is what is changed from the Pump shotgun:

+Pellets
+Damage
+Recoil
+Fire Rate
-Magazine Size
-Accuracy
-Spread
-Range
-Damage over longer ranges

VerticalPunch = 4 -> 6
SpreadPerShot = 1 -> 6
MinDuckingSpread = 0 -> 0.2
MinStandingSpread = 0.8 -> 0.9
MaxMovementSpread = 1.5 -> 1.7
PelletScatterPitch = 5.0 -> 6.0
PelletScatterYaw = 7.5 -> 8.5
Damage = 250 -> 351 (13 pellets * 27 damage each)
Bullets = 10 -> 13
RangeModifier = 0.7 -> 0.6
Range = 3000 -> 2250
CycleTime = 0.5 -> 0.3
ClipSize = 8 -> 2