M1 Rifle - Garand - Troubleshooting...

Operating Stage	Malfunction	Probable Cause	Remedy
Loading	Cartridge clip inserts only with difficulty.	Deformed cartridge clip.	Replace the clip.
		Broken clip ejector.	Replace the clip ejector.
		Interference between bullet guide and follower arm.	Replace the faulty part.
	Bolt releases before clip is latched into place.	Worn or broken clip latch.	Replace the clip latch.
		Worn or broken clip latch spring.	Replace the clip latch spring.
		Excessive radius on operating rod or operating rod catch.	Replace the faulty part.
		Bullet guide is too high at the accelerator bearing point.	Replace the bullet guide.
	Bolt does not release when clip is latched into place.	Burs or insufficient radius on operating rod or operating rod catch.	Repair or replace the faulty part.
		Bullet guide is too high at the accelerator bearing point.	Replace the bullet guide.
Operating Stage	Malfunction	Probable Cause	Remedy
Feeding and Chambering	Failure to feed ammunition.	Lack of lubrication of moving parts within the action.	Clean and lubricate the moving parts.
		Defective or worn parts within the action.	Replace the faulty parts.
	Failure to chamber ammunition.	Lack of lubrication of moving parts within the action.	Clean and lubricate the moving parts.
		Dirty chamber.	Clean the chamber.
		Defective or dirty ammunition.	Replace or clean the ammunition.
	Bolt fails to close tightly and lock into place.	Dirty chamber.	Clean the chamber.
		Dirty locking recesses in chamber.	Clean the locking recesses.
		Lack of lubrication of moving parts within the action.	Clean and lubricate the moving parts.
		Damaged or deformed cartridge.	Remove damaged cartridge, inspect other ammunition.
		Extractor does not open far enough to pass over the cartridge rim, or ejector is frozen in place.	Clean the bolt assembly, replacing parts as needed.
		Operating rod is binding, possibly against the stock.	Replace the operating rod if it is misshapen, or remove wood from the stock as needed.
		Weak or broken operating rod spring.	Replace the faulty part.
		Damaged or deformed bolt or receiver.	Replace the faulty part.
		Insufficient headspace.	Verify correct chamber reaming and headspace.
Operating Stage	Malfunction	Probable Cause	Remedy
Firing	Slam fire (gun fires on its own as the bolt closes) or out of battery fire (other unintended firing when bolt is not closed and locked).	Defective ammunition.	Remove defective cartridges, inspect other ammunition.
		Wrong ammunition.	Unload and remove inappropriate cartridges, inspect other ammunition.
		Incorrect chamber dimensions or headspace.	Correct the chamber dimensions, or replace the barrel and properly headspace the new chamber.
	Pressure on trigger does not release the hammer.	Deformed trigger, pin, or hammer.	Replace the faulty part.
	Hammer falls but does not fire.	Light strike of the firing pin on the primer.	Replace the hammer spring.
		Hammer spring housing damaged.	Replace the hammer spring housing.
		Firing pin defective, including not protruding far enough from bolt face when struck.	Replace the firing pin.
		Trigger group defective.	Replace the trigger group.
		Defective ammunition.	Remove defective cartridges, inspect other ammunition.
Operating Stage	Malfunction	Probable Cause	Remedy
Ejecting	Bolt does not unlock or open.	Plugged gas port or dirty gas cylinder.	Clean the gas port and gas cylinder.
		Gas cylinder lock screw leaking gas.	Clean and tighten gas cylinder lock. If it has a leaking valve, replace it.
		Gas cylinder loose on operating rod piston, leaking gas.	Measure cylinder and piston: Gas piston: 0.525" min. o.d. Gas cylinder: 0.532" max. i.d. Replace gas cylinder if necessary.
		Chamber dirty, or moving parts dirty or lacking lubrication.	Clean chamber and action, lubricate moving parts.
		Barrel external diameter too small at gas port, leaking gas.	Replace the barrel.
		Follower arm pin worn.	Verify follower arm pin hole diameter, replace follower arm pin.
		Follower arm bent or out of tolerance.	Replace follower arm.
	Operating rod disengages from the bolt while cycling.	Operating rod lug is worn, or the operating rod spring is kinked.	Replace the operating rod or spring.
		Receiver guide rail for operating rod is excessively worn.	Replace the receiver, or rebuild the receiver's guide rail.
	Failure to extract cartridge from chamber.	Dirty chamber.	Clean the chamber.
		Defective ammunition.	Remove defective cartridges, inspect other ammunition.
		Broken extractor.	Replace the extractor.
	Failure to eject the extracted cartridge.	Broken ejector pin or spring.	Replace the faulty part.
		Ejector is binding within the bolt.	Clean bolt assembly, including ejector hole. Inspect ejector and remove any burs.
		Short recoil (bolt is not pulled back far enough).	See "Short recoil" section below.
	Failure to eject cartridges in correct direction, 30-60° to right of firing direction.	Inadequate lubrication of moving parts.	Lubricate the moving parts. Cartridges should eject to roughly 30-60° to right of firing direction. As the action becomes dirtier and less well lubricated, the direction will shift further to the right and then continuing around to the rear.
Operating Stage	Malfunction	Probable Cause	Remedy
Cycling, reloading next round, ejecting empty clip	Short recoil — the bolt is not retracted far enough to complete the cycle.	Ammunition does not develop adequate gas port pressure to cycle the action.	Gas port pressure should be 6000±2000 p.s.i. Faster-burning powder may not develop adequate port pressure without developing dangerously high chamber pressure. Always use appropriate ammunition!
		Carbon built up in gas port or gas cylinder.	Clean the gas port and gas cylinder.
		Undersized or out of round operating rod piston.	Replace the operating rod.
		Oversized gas cylinder.	Replace the gas cylinder.
		Barrel external diameter too small at gas port, leaking gas.	Replace the barrel.
		Operating rod is binding, possibly against the stock.	Replace the operating rod if it is misshapen, or remove wood from the stock as needed.
		Gas cylinder lock screw leaking gas.	Clean and tighten gas cylinder lock. If it has a leaking valve, replace it.
		Weak or broken operating rod spring.	Replace the faulty part.
		Burs on bolt binding in the receiver.	Remove the burs from the bolt.
		Damaged or deformed receiver.	Replace the receiver
	Bolt cycles very firmly but does not chamber the next round.	Excessive gas port pressure cycles the bolt so forcefully that it slams shut again before the follower can lift the next round into the bolt's path.	Gas port pressure should be 6000±2000 p.s.i., slower-burning powder may develop excessive port pressure when loaded to produce desired velocities. Always use appropriate ammunition!
	Hammer is not cocked to fire the following round.	Defective trigger group.	Replace the trigger group.
	Failure to eject the empty cartridge clip.	Clip ejector worn, weak, or broken.	Replace the clip ejector.
		Operating rod catch deformed or broken.	Replace the operating rod catch.
	Premature cartridge clip ejection.	Worn cartridge clip detents.	Replace the cartridge clip.
		Weak clip latch spring.	Replace the clip latch spring.
		Worn clip latch.	Replace the clip latch.
		Bent follower rod or worn follower rod forks.	Replace the follower rod.
		Worn follower arm.	Replace the follower arm.
		Worn or deformed operating rod catch or bullet guide.	Replace the faulty part.
		Follower rod rubs on operating rod catch.	Replace the deformed part — follower rod, clip latch, or operating rod catch.
	Bolt is not held rearward after firing the last round, and the clip is jammed by the bolt and held inside the action.	Bolt is not moving far enough rearward.	See the "short recoil" section above.
		The clip latch is binding.	Replace the clip latch.
		Operating rod catch or operating rod is bent or deformed.	Replace the faulty part.

Proper Operation:

• Loading
  • Starting with a completely unloaded gun, the operator pulls back on the operating rod handle until the bolt locks in the fully open position. Two mechanisms hold will hold the bolt back:
    • The operating rod catch engages a notch on the operating rod, under the rear of the barrel. This prevents the operating rod traveling forward and bringing the bolt with it.
    • The follower raises far enough to block the bolt itself.
  • An en-bloc clip filled with 8 cartridges is inserted into the space between the bolt and chamber, and pressed down into place. This presses the follower down into the action, but the operating rod and bolt are still held back by the operating rod catch. The clip locks into place, although it could be released by depressing the long clip latch down the left exterior of the receiver.

• Feeding and chambering a round
  • The bolt is pulled back slightly, and the operating rod catch now disengages because the follower has been depressed.
  • The bolt is released and allowed to slam shut, pulled by the operating rod. This strips the top cartridge out of the clip and pushes it into the chamber.
  • The bolt should fully close and lock, rotating slightly to its right with the locking lugs engaging their recesses in the receiver.
    • The bolt face is firmly against the rear face of the cartridge case.
    • The bolt's extractor is snapped into the groove around the base of the cartridge case.
    • The bolt's ejector is depressed into the bolt body.

• Firing
  • The trigger is pulled, disengaging the trigger lugs from the hammer hooks and allowing the the hammer to swing forward under the pressure of the hammer spring.
  • The hammer strikes the tang of the firing pin, which extends through the bolt. The forward point of the firing pin strikes the primer and fires the round.

• Ejecting the fired cartridge case
  • As the bullet passes the gas cylinder port near the muzzle, hot gases are directed through that port into the gas cylinder. That pushes against the piston formed by the forward end of the operating rod, driving the operating backward. The gas port pressure needed for operation is 6000±2000 p.s.i. (41,370±13,790 kPa).
  • The rearward action of the operating rod unlocks the bolt (rotating it back slightly clockwise, as seen from the rear) and driving the bolt back.
  • The extractor, a small spring-tensioned hook around the bolt face, pulls the now empty cartridge back by the groove around its base.
  • The ejector, a small spring-tensioned piston extending from the bolt face, pushes against the cartridge base opposite of the point where it is hooked by the ejector, rotating the cartridge and ejecting it from the action.

• The rest of the bolt cycle, preparing the next round
  • The bolt and operating rod reach the end of their range of travel, and the operating rod spring now brings them back forward "into battery", or back to the firing configuration. The next round is stripped from the clip and chambered.
  • However, if that last round was the last one in the clip, the follower has moved upward far enough that the clip latch disengages and the operating rod catch engages. This has two results:
    • The bolt and operating rod are locked back with the bolt open.
    • The empty clip is ejected.