Looking for GBB USP .45
Hello guys, the title says it all. I recently picked up a BB firing HK USP .45 from our local hunting store and I fell in love with it. The gun is very solid and can shoot around 6-7 mags in a can of Co2. However, the only downfall is that the gun does not have a blow back effect. Can anyone direct me to where I can find a bb / airsoft USP .45 that has GBB? Thank you.