The last post is correct I built a full size UZI pistol but used a semi mini bolt. I didn't use the correct buffer but used the original full length with a cut down AR-15 buffer to work the striker. I had some square tubing I had to cut open and mill out to use as the missing receiver section. I did the correct mods the the trigger housing and grip to make it semi only. It has taken a lot of work but now that I'm done it is worth it. Also, I welded in 2 blocks of steel on each side of the barrel to make up for the shortened bolt. The FA bolt is longer.