I used the M-16 in my service, it was fine. I hear the SAR-21 is
fine too.
Both shoot reliably on the range and jam often with the plastic
blanks we train with. The blanks make less gas and have a soft body
that is ruptured/deformed by the gas or tears when extracted. Of
course the SAR-21 would hold up better in dirt.
This SAR-21 was fired with a missing part, but it is what a
SAR-21 would look like if it exploded.

The K-2 has a bolt carrier group derived from the M16 and gas
operating system is derived from the AK-47, which is the same
system as the SAR-21.
Continuing where we left off last time. What I don't get is why
your army is so brutal. It doesn't rule the country anymore. People
could make it change if they shouted loud enough, istead everyone
supports it in public but hopes their son evades it in
practice.