Something that we would love to see available for the airsoft market but it may just fit existing AR Gas Blowback Rifles. The Sharps Bros. The Jack Lower Receiver is announced to be available at Spike's Tactical. It's a head turner and will make your AR look mean and deadly. If gas blowback owners have tried some of the other models from Sharps Bros. such as the Hellbreaker or the Warthog, we would love to hear if they fit.