There is a Legacy version here.

Kickback

Source NPC Core pg. 50
A kickback weapon is extra powerful and difficult to use due to its high recoil. A kickback weapon deals 1 additional damage with all attacks. Firing a kickback weapon gives a –2 circumstance penalty to the attack roll, but characters with +2 or more Strength ignore the penalty. Attaching a kickback weapon to a deployed bipod, tripod, or other stabilizer can lower or negate this penalty.