The alarm that went out was "the Regulars are coming". Meaning the regular army. It was the colonists own army which was being used to confiscate civilian arms. Citizens of Boston were forced to disobey the order to turn in their weapons and had to smuggle them out of the occupied city in order to keep them.
It was not the firing of the regular's guns which raised the alarm, but several mounted riders including Paul Revere.
You can bet if our army is ever instructed to confiscate the arms of civilians, the army will have every weapon known to man at their service. You and I may not have silencers, machine guns, helicopters, or anti-tank missiles, but the forces sent to tyrannize us will have all this and much more.