“Pounds” are the amount of
resistance ("pull") required to release a firearm's hammer or firing pin, which fires the weapon. Also known as “pull weight”.
Most pistols are three pound or four pound trigger assemblies.
"Pound" is NOT related to caliber, style, size or type of firearm, as anyone who is familiar with firearms can tell you.
A two or three pound trigger pull is common for single action handguns, while four or five pounds is
the standard for
double action pistols.
Most combat rifles, semi or automatic, usually come standard with a 4-7 pound pull weight, although any trigger weight can be adjusted by altering the spring(s) in the trigger assembly.
As far as accuracy goes, a lighter pull weight requires less flexing of the hand on the trigger and grip, which usually means a more accurate shot. When you pull hard on a resistant trigger, your hand will naturally tend to pull the nose of the gun upward, which sends your round
off the mark. That means you need a few less “pounds” of
resistance. Rifle triggers are usually tougher to pull back, since you’re holding the weapon with both hands at two different points and muzzle jump is obviously less of a problem for accuracy.
A trigger with one to two pounds of pull is known as a “hare-trigger,” meaning the gun is fairly “jumpy” (like a rabbit or hare) and requires very little pressure to fire.