what is the purposes of a sear on a ar 15

A pistolsmith doing a trigger job may adjust sear pressure a bit but minimum tension should never be set less than one pound. Insufficient sear spring tension can cause the hammer to follow the slide down as it moves forward during loading or firing.

This leg applies pressure directly to the sear causing it to bear against the hammer until the trigger pushes it out of engagement. Viewing the spring from the rear the longest leg should be to your left.

Let's look at the function of this spring and its relationship to the 1911 trigger mechanism. Sear springs don't usually wear out and you probably don't need one in your emergency stash of spare parts but they may occasionally require adjustment to prevent malfunctions. A flat piece of spring steel slit in two places to form three legs which are bent individually to adjust tension against the relevant fire control parts. But to deliberately drill a hole for “aesthetics” seems like a waste of time.It doesn't look like much. Sure there are lowers with the “AUTO” markings on them and I do not have a problem with that. This is like putting Ferrari badges on a Pontiac Fiero. Regardless of the legal ramifications, I question the need to drill a hole and welding a pin to fake the look of a full auto. Remember the recall on the IWI Galil ACEs? They were recalled for having a third pin hole in their receivers even though you could not simply drop a full auto sear in them either, ATF still considers them a machine gun and must be dealt with accordingly. Plenty of people commented and advised him that he has made a machine gun according to the ATF. It is right above the selector switch in the photo above. He drilled a third pin hole in the receiver with a “random sized” drill bit. Gun Addiction is an Instagram account and he posted a photo of his “cosmetic” modification. Rationale and ignorance is not something the ATF takes kindly. This was posted in a Facebook group and the ignorance is astounding.

What is the purposes of a sear on a ar 15