Getting the Parts
The receiver is the component that defines the gun. You will need to buy this through a dealer holding an FFL or Federal Firearms License. You will probably want to use a new barrel, there are several sources of these. For the rest of the parts, you can purchase them separately. However, many dealers sell bags of parts. A bag of parts may or may not come from the same rifle. Even if they do, that rifle may have been refurbished, so they parts in a typical kit will have been manufactured over a wide range of years.
We got the parts from a variety of suppliers. ODCMP at Camp Perry was the source of my receiver.
What A Country supplied the barrel. It's a Citadel barrel, newly manufactured, so we had to do the finish reaming as described on the next page.
We got some individual parts (gas cylinder assembly, components of the action) from "Italian Andy", a guy in Italy who sold parts over eBay until they stopped gun part sales. Now he sells through gunbroker.com
We got a parts kit of most of the remaining parts from Dupage Trading Company or similar. I think these were NATO returns from either Greece or Denmark, rifles they had kept stored somewhere in case of Soviet invasion. Greece used the M1 Garand until the late 1970s, and the honor guard on Syntagma Square in Athens still carries them.
Once we had the parts, we parkerized most of them. I have another page describing the parkerizing process.
The exception to the parkerizing is the gas cylinder. It is made of stainless steel to withstand the high gas temperatures. This made for a fairly large and very reflective part near the muzzle. Back in the day, the men in the field re-blackened their gas cylinders with smoke from a campfire, a candle, or a trusty Zippo.
Now we use chemical blackening. This isn't a colored coating, like paint, but it is a chemical reaction that darkens stainless steel. Think about that: it changes the color of otherwise stainless steel. So yes, it involves some rather caustic chemicals! We used Caswell's stainless steel blackener.
Other places we looked at, or that my friend used as a source for his, included Boyd's Gun Stocks.
I was pleasantly surprised to find that some sources of Garand parts sell through Amazon.