View Full Version : information on the assembly of an M-1 Garand

7.62 NATO (x)
December 22, 2000, 10:30 PM
I have recently purchased a Berretta parts kit and a new commercially manufactured receiver. Can anyone give me any helpful hints to the proper assembly of the barrel to the receiver? How about the headspacing, is this something that I may be able to do myself or does this require proper gunsmithing?

Oleg Volk
December 22, 2000, 11:40 PM
I asked my gunsmith about it and here's what he said:
if the headspace is excessive, you'd need a different barrel. If insufficient, you can brind away on the locking lugs. You need a set of gauges to test headspacing. Might make sense to pay someone to do it for you. The other issue is timing, making sure the gun doesn't try to unlock while the pressure is still too high, for example. Hope I got the details right, as I am not qualified to assemble an M1 either.
I would let someone else do it for you or you could fish for info here http://www.memorableplaces.com/m1garand/ and here http://www.jouster.com/cgi-bin/garand/garand.pl You might also wish to check the receiver: if it is a re-weld, it may or may not be safe to use.

James K
December 24, 2000, 11:50 PM
Hi, 7.62 and Oleg,

Why do people always make putting together a rifle from a kit sound so simple?

If the new receiver is one of those made for Century Arms, you might want to read the information on http://www.fulton-armory.com.

There is always a potential problem with installing a used barrel on a rifle like the M1. New barrels are short chambered, that is they are made with too little headspace. When a new barrel is installed, a try bolt (actually a gauge, not any old bolt) is used, or the original bolt is used, and the chamber reamed to the correct headspace. With a used barrel, headspace may be too short, in which case the reamer can be used, or too long. If it is too long, a number of bolts can be tried to see if one will bring headspace within specifications. If this fails, a new barrel is the only solution.

(Anyone who says, "Oh, just set the barrel back" probably does not know what he is talking about. The common practice with sporting rifles of cutting the barrel and setting it back one thread will not work with the M1 because the barrel would then be too short and that would destroy the relationship between the barrel and the operating rod as well as the stock fittings, etc.)

In addition, the M1 does not have witness marks, so a gadget called a "barrel timing gauge" must be used to get the barrel lined up and make sure the front sight and gas cylinder are in proper alignment with the receiver. (This is not merely to get the right sight picture - the gas cylinder and operating rod must be lined up properly with the receiver or the op rod may jump out of its track.)

BTW, insufficient headspace is always adjusted by reaming the chamber. Grinding the locking lugs can be done, but is very poor practice and I would question the ability of any gunsmith who recommended it.


Oleg Volk
December 24, 2000, 11:53 PM
I did not quote my gunsmith correctly.

January 15, 2001, 01:55 PM
"The U.S. .30 Caliber Gas Operated Service Rifles" A Shop Manual. The book goes into great detail.

Otherwise, I second what Jim Keenan said.

Good luck with the receiver. Mine came from CMP and worked beautifully.

4V50 Gary
January 15, 2001, 09:25 PM
The whole matter of assembling an M1 is not a simple one. Headspace can be a matter of setting the barrel back (in which case the timing better be proper), replacing the bolt, or checking to see whether the corresponding locking points on the receiver aren't too worn. For a novice without the proper tools to assemble and gauges with which to ensure proper assembly, it's a daunting task best left to the gunsmith.

Unlike the AR-15 (and its clones), the M1 Garand does not lend itself to home gunsmithing (other than trigger jobs and glass bedding).