M1 Carbine Won't Cycle

First check the gas piston.
The Iver Johnson was made to (more or less) USGI designs, and comes apart like the GI Carbine. A USGI Carbine manual can be used when working with the IJ.

Remove the action from the stock, remove the operating slide and look on the underside of the barrel.
The gas piston sticks out of the gas cylinder by about 3/8".
The piston must move freely in and out about 3/8".
If it doesn't, the rifle will not operate.

If the piston is frozen, you'll have to buy a piston nut wrench to disassemble the gas system.
To do this, get a GI manual that shows Carbine disassembly including the gas system.

Causes of piston freeze are rust or allowing lubricant or solvent to get into the system. When the Carbine is fired, super heated gas taps into the gas cylinder to push the piston to the rear.
Any lube or solvent instantly burns to a sticky, tar-like substance and causes sluggish piston movement.
Enough, and the piston can freeze up.
The Carbine gas system is never lubricated, and the Carbine is cleaned sights-down on the bench to prevent solvent or oil from draining into the system.

If the piston is moving freely, there's a chance the gas port itself is plugged.
Cleaning requires removal of the gas piston and nut.

Many surplus parts dealers have Carbine ordnance manuals showing how to properly disassemble the gas system, and sell the piston nut wrench.
 
I purchased a piston nut wrench and removed the piston and associated nut. They were both clean and free of debris. The gas hole was another story; it was completely clogged with god knows what. I stuck a small wire in there to attempt to clean it out while spraying it with aerosol gun lubrication.

I plugged the bolt end of the gun with my thumb and blew into the business end to see if i could free the debris from the gas port, nothing happened - it was air tight.

If the gas port was clean and working properly the air from me blowing into the barrel would emit through the gas port, shouldn't it?

What is the best way of cleaning the port out?

My small wire and aerosol spray combination has been an epic fail; not only am I lightheaded from blowing in the barrel and huffing the aerosol spray - my wife is yelling at me for stinking up the house (with the gun spray).

Thanks for the help.
 
I would bet someone shot unjacketed lead bullets at some time in the past. That would mean a mixture of bullet lead and powder residue is clogging the gas port.

A drill bit of the proper diameter would clean th gunk out of the gas port. But I don't know what the proper diameter for the drill bit would be. I would start with a small bit and work up. Turn the bit between your thumb and forefinger, not with an electric drill motor. You'll be able to tell the difference between the bit cutting crunchy lead/powder residue and hard barrel steel.
 
Does the housing for the gas piston and piston nut come off the barrel?

Its difficult enough getting a small wire in the gas hole and then up into the barrel, I cant imagine trying to get a drill bit in there.

I wish I had a diagram or picture of the actual gas system, from the hole in the barrel to the piston, which shows the path of gas blowback.

Thanks for the help, again.

Jager
 
After checking an Inland and Rockola, the gas piston housing is swaged onto the barrel.

The gas port is then drilled from the bottom of the piston housing, through the piston chamber and through the lower half of the barrel to reach the bore.

The small angled hole you see on the bottom of the gas piston housing is the bottom of the gas port.

A small drill bit will fit through the same hole in the bottom of the gas piston housing and clear the gunk out of the gas port. Spin the bit between your thumb and forefinger so you don't remove more barrel steel.

I last owned a Universal some 25 years ago and sold it when I found the Rockola. As I recall with fuzzy memory, the gas piston housing was brazed or welded to the barrel and it had the same angled gas port hole in the bottom of the gas block.
 
I found a large amount of copper and carbon clogging the gas port and removed some of it with the drill bit method.

The problem now is that the angle of the gas port - between the barrel and the housing - is also completely clogged and I cant get the drill bit at the proper angle to clean the junk out.

Is there a solvent that can be poured or sprayed into the housing that will eat away the copper / carbon and self clean my port?

Thanks for the help.

Jager
 
Dfariswheel said:
The Iver Johnson was made to (more or less) USGI designs, and comes apart like the GI Carbine. A USGI Carbine manual can be used when working with the IJ.
Click to expand...

I thought Iver Johnson bought out Universal in 1983 and late production Iver Johnson carbines used the universal design and parts.

I had a second generation Universal carbine that I shot alot and it was great. I also had a 3rd generation that wasn't so good.
 
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