When pulling out the SMG for the first time, you might notice that you prime the round before you can fire which is entirely accurate. What isn't accurate and wastes a lot of time is the priming animation playing even after you've already "primed" your weapon. So while the round is already in the chamber, if that animation plays again, it will eject the round each time that happens. This happens every time regardless of the ammo count within the clip at the time. This animation can be detrimental to ones ability and speed by increasing the amount of time

After picking up the shield, the impacts are not on the shield, but left floating in air.