Here is another one to confuse you.
Factory FBI MP5/10 with SF trigger Group. Note how I go from SF to F/A without changing the selector despite long trigger pull. Magic!
Ok, @Renegade I think I understand what is going on here.
You have a post sample MP5SF (model designation on the form 3)
MP5SF's come with front pushpin holes and are machine guns. (pushpin hole is what atf defines as a machine gun receiver)
What you seem to think, is that an MP5SF comes capable of full auto fire. This is true (to some extent) but the original trigger group that the gun came with was identical to the one @Oicani posted.
You think that it came from the factory with the top trigger group in your posted photo. (which is an unmodified hk full auto trigger group)
What probably happened, is that whoever had the gun before you changed the trigger pack so it could actually shoot full auto. This leaves you to think that since you have an MP5SF, and it can shoot full auto that you are right. However, MP5SF's came with trigger groups like Oicani and I posted.
Renegade, I dont want you to spend any money to learn....but hypothetically, lets say you bought this: Heckler and Koch MP5SF Complete Trigger Group (0/1)
You take that and put it on your post sample (or pre sample?) MP5.....will it shoot full auto? If not, what fiddling would you need to do to get it to shoot full auto?
The part number for that complete MP5SF trigger group is 216228, you could call up HK and order it directly from them if you like.
Last edited by Renegade; 07-27-2017 at 12:55 AM.
Hk makes them as semi auto only packs, and @Oicani was kind enough to post a picture of the actual trigger frame/box from an SF pack.
Maybe at one point the SF packs did come with a trip level. They don't now.
As for making one shoot full auto with a trip lever? I think I know that trick! Good stuff Renegade!
"...but just like every other clone, they are copies of the original and copies are never as good as the original."
Maybe that's the difference. Mine is from a 9mm gun.