Im considering getting a 9mm upper...but I have a few questions. PS I did a search but couldnt find the answeres.
1. Are 9mm upper blowback....or gas operated and do they use the locking lugs?
2. How are they fed into the chamber...with a barrel extension? EX. In this picture the magazine is in the middle of the magazine well...but ive seen some where the magazine is all the way forward.
3. Any pictures of the bolt face or of the bolt locked back would be great!