Angry Gun is on a roll with their upgrade kits as they have been releasing left and right new products to make a gas blowback airsoft user happy for the rest of the year. The video below shows their 300% Recoil Kit install in a KWA LM4 Gas Blowback Rifle and indeed the recoil is strong which might be a little bit unwieldy for some and think that it's a jackhammer.