Username: Password:

M1 Carbine Images

Author Topic: 4. Carbon or Foreign Matter in the Gas Port  (Read 5178 times)


  • Administrator
  • *****
  • Posts: 62
4. Carbon or Foreign Matter in the Gas Port
« on: October 20, 2012, 12:50:45 AM »
The gas port is a hole drilled in the barrel. It's function is to allow gas to flow into the gas cylinder; facilitating the cycling of the rifle. The dimension of this hole is important and should be checked prior to use. If the hole is plugged with carbon fouling then insufficient gas flow can lead to short stroking of the rifle. If the hole is too large, excessive pressures can develop causing damage to the op-rod or receiver heel. The easy way to inspect the gas port is to purchase two numbered drill bits from your local hardware store. You want to purchase a #47 and a #46 drill bits.  These will become our GO and NO-GO gages respectively. The #47 drill bit should fit into the gas port. If the gas port is plugged with fouling gently spin the drill bit with your fingers as you clean the port. DO NOT USE A POWER TOOL.  After the port is clean, take the #46 drill bit and using the smooth end (not the drill end) verify that the drill bit will not fit into the gas port.


Featured Video

How to disassemble M1

Recent Posts

The Gunsmith’s Reference Library by edog
April 26, 2018, 11:28:58 AM

Enjoy Our Free Arcade!

Image Gallery


M1 Garand Images

Powered by EzPortal