I reload 5.56 military and 223 factory brass. No difference
except the crimp on the primer. Some of the mil brass is
lighter than factory.

Helped a friend sight in his CA variant.

About 5 shots in 6" was as good as we could get off a bench at
100 yards. Minute of deer at 100 yards. Legal for deer in CA too.

They are very light. Much lighter than any other rifle I have seen.

An old school similar set up for hunting survival would be a short lever action 357 mag or 30/30. Probably more accurate than the Kel-tec.