M16-M4 Inspection Procedures.
Many times M4C members have inquired about inspecting their weapons and the various procedures that are used. In this sticky I am going to show the procedures and gages that are used in the military when conducting an annual or pre-deployment inspection on the M16 FOW.
You will have to bear with me as I may miss a few things as I am compiling this. These procedures aren't listed in any particular order.
First I am going to show some of the gages used.
Top gage is a barrel straightness gage.
Far left (not visible) is a firing pin protrusion gage.
Next gage is a "FIELD" headspace gage. This is a MILSPEC gage and not a civilian copy.
Next is a gage to measure the hole where the firing pin protrudes the bolt face.
Gage with the black handle is a taper plug gage. It is used to measure the holes for the hammer and trigger pins. Military receivers use .155 diameter pins. The gage calls for rejection if the gage penetrates those holes (.163 diameter).
The next item is a reflector tool to inspect the barrel.
The next items is a carrier key tool. It is used to flare out the carrier key in the event that it gets dinged or dented.
Attachment 5559
The first inspection being shown is the checking of the holes for the hammer and trigger pins in the lower receiver. You insert the gage and then rotate it to see if the gage penetrates in any position. If not then you are a GO.
Attachment 5561
Attachment 5562
The next inspection is the barrel straightness test. In order to do this correctly the barrel must be clean. The initial test is conducted by tilting the barrel slightly and inserting the gage via the muzzle end. If gage passes freely then you are a GO. If not, then you must pass the gage through the chamber end holding the barrel in a vertical position. If it passes you are a GO. If not, then you must follow barrel straightening procedures as outlined in TM 9-1005-319-23&P.
Attachment 5563
Next is the checking of the headspace using a MILSPEC "FIELD" headspace gage.
Attachment 5564
