here are a few off the top of my head:
LTCF=license to carry firearms (what PA, which is pennsylvania, btw--which is "by the way"
calls our carry permits)
CCW= concealed carry weapon or carry a concealed weapon
CC= concealed carry
OC = open carry
ND = negligent discharge (when you fire your gun when you did not intend to)
AD = accidental discharge (very rare...some people incorrectly label NDs ADs, though)
DA = district attorney.
SO = sheriff's office
PD = police department
PPD = usually philly police department on this forum
EBR = evil black rirfle
BRD = black rifle disease
OP = original post or original poster
BOB = bug out bag
GLOCK = perfection