I can tell you that there was a Beverette with a BP Defiant turret used for airfield defense at an RAF base "somewhere in England" I scratch built a standard Beverette once and the article had a picture of that very beast !!! I wanted to build that one but had no way to make or source that turret. I been wanting to do another one ( the original got trashed in moving) and now I can !!!!!! My bank account may not like it but , I WANT ONE !!!! I MUST HAVE ONE !!!!!!!