Not everyone uses their rifles in the same way or for the same reasons.
Flat absolute statements of “good enough” may not be for some folks.
Just because you don’t have the need to take a shot at 200 or longer doesn’t mean someone else doesn’t.
We need to stop assuming everyone has the same frame of reference.
The truth is a 50 yard zero does not always equal a 200 yard zero and if you are looking for the ability to make a 200 yard precision shot, which is something the AR platform is completely capable of, you need to confirm at distance.
That's kinda what I was thinking too? Zombie shots at 200 yards? Taking out a neighbor down the street at 200 yards? Didn't think so.
Most defensive uses would be even inside the 50 yard mark, or 10 or less like you mentioned.
So I just bought a surplus Star BM 9mm from J&G Sales a few weeks ago and I have been having some issues that I can't seem to take care of. Mostly upon extraction, spent cases are left in front of the bolt and jam the slide open. I was also experiencing some stovepipes. See the attached pictures.
(Note: This is a torn up casing and a snap cap used to re-create the look of the jam, I wasn't shooting in my house)
When I first got the pistol, I had an average of 7 to 8 malfunctions out of every 100 rounds that I put through it, with 3 different brands (Winchester white box, Fiochi, and SIG Elite Performance) of 115 grain FMJ target ammo. Of these malfunctions 3 to 4 were the jam described above, 1 to 2 were stovepipes, and the others were failures to extract where the casing was still partially in the chamber.
After discovering these issues I have replaced the recoil spring assembly, barrel bushing, and extractor and spring. Replacing these parts has cut the number of malfunctions down to 3 to 4 per 100 rounds, 2 to 3 being the failures pictured above, and 1 being a stovepipe. The failure to extract malfunction seems to have been taken care of though. I'm at my wits end at this point. I want this pistol to run reliably but I don't know what else I can do to fix it. Does anyone have any ideas?