M14/M1A Gas Piston / Gas Plug Cleaning Drills

You need a set of drills to clean the gas plug and gas piston on the M14/M1A rifle.  Sadlak makes these and to buy all three would cost you $43.48 from Midway.  I made my own for less.

The correct drill bits are letter and number gauge sizes, not available at your local hardware store.  I ordered the drills and the handles from MSC Industrial Supply:

01008150, #15 aircraft length drill, $4.71
01189158, O gauge jobber length drill, $3.39
01189166, P gauge jobber length drill, $3.68
00651042, 1' x 4" file handle, $1.31 x 3 = $3.93
Shipping $11.60
Total $27.31

The #15 and the P are for the gas piston and the O is for the gas plug.  The shipping was a bit high, but they arrived in two days.  You're still saving money.

I drilled out the inside of the handles with progressively larger drill bits until I could squeeze the drill in.  I had to use pliers to hold the ends of the wire wrapping on the handles.  The ends of the wire wrap stick into the center cavity and want to push out while you are drilling.

I used linseed oil on the handles, and engraved the O and P because it is hard to tell them apart by looking.  You need to grind down the tips of the drills so you are not drilling a hole in your gas cylinder or gas plug when you clean it.

To remove the gas plug, you need a 3/8" box end wrench or M14 combo tool and a gas cylinder wrench.  The best deal on a gas cylinder wrench is Fulton Armory for $9.95.  The gas plug is torqued to 130-150 inch pounds.  Make index marks with a Sharpie on the gas plug and cylinder before removing the gas plug.  Line them back up when you reassemble and you should have the same torque.  Use anti-seize on the gas plug threads.

I've seen various recommendations on how often to clean the gas piston/cylinder.  I clean it every 1,000 rounds or whenever you can't hear the piston move back and forth inside the cylinder when you tip the rifle with the bolt locked open.