stylesgre.blogg.se - M1 carbine national postal meter serial numbers

Headspace is specific to the bolt and barrel.

"Go" Gauge: the bolt should rotate and lock into the closed position.

If the bolt rotates and locks on a "Field" Gauge the carbine should not be fired

"Field" Gauge: the "Field" Gauge is used if the bolt rotates and locks with a "No Go" Gauge.

"No Go" Gauge: the bolt should stop just short of rotating, before it goes into the locked position.

The stripped bolt is placed within the receiver and slid to the rear.Įach gauge is individually placed in the cleaned chamber, the bolt is then moved forward towards the breech until the bolt stops: The carbine is disassembled as is the bolt. Use of a headspace gauge is pretty simple and straight forward. Retail by most large gun supply retailers (Brownells, Cabelas, Midway). This can be done by a qualified gunsmith or by purchasing headspace gauges for the U.S.30 Caliber Carbines, manufactured by several different companies and sold When acquiring a used M1 Carbine the headspace should be checked before firing the weapon. This distance is referred to as "headspace" and by design controls expansion of the casing and the gases generated when Gas piston nuts were normally staked in place to prevent them from rotating out.Īs with all firearms but particularly center-fire semi-auto firearms and particularly those made for use as military rifles, the distance between the face of the boltĪnd forward end of the chamber is critical.

Gas pistons were unmarkedĮxcept by the subcontractors who manufactured them for Inland Mfg. Gas pistons remained unchanged throughout production. Right: Later Gas Piston Nut, countersunk to allow more piston movement Not toīe confused with BI marked barrels manufactured by Brown-Lipe-Chapin for Inland (see below).Īrrows indicate openings for securely staking the gas piston nut to the gas cylinder Note: BI marked gas piston cylinders were manufactured by B & P Motor Company for Inland. The subcontractors were assigned different markings. Inland also subcontracted a number ofĬompanies to manufacture additional gas piston cylinders. Inland manufactured their own gas cylinders, occasionally marked II or I-I.

Gas cylinders having the name Rock-Ola were used only on Rock-Ola barrels. With the exception of Rock-Ola, prime contractors did not place their entire name on their Swaged gas cylinders were normally manufactured by the company who manufactured the barrel. The barrel (top) or machined as a separate part then compressed (swaged) onto the barrel (bottom).Ĭut-away showing Swaged Gas Cylinder pressed onto barrel and gas port drilled through gas cylinder and barrel The gas cylinder was machined integral with Gas cylinders were manufactured by one of two methods. Government have 4 lands and grooves.Ĥ lands and grooves, shown from chamber end of the barrel 30 Caliber Carbine barrels manufactured under contract to the U.S. *measured from the muzzle to the end of the skirtĪll.