Uh, guys, if you read the US military manuals on the thing, or if you have Hatcher's "Book of the Garand", you will find that the front handguard is DESIGNED to be loose. Tightening it in any way WILL affect how the rifle shoots.
BTW, here's a nasty little trick you can do with a Garand.
The Garand rear sight is adjustable in 1-minute clicks. The front sight is 4 minutes wide. Put your rear sight out 2 clicks, then aim with the CORNER of the front sight. REALLY tightens your groups up.
Serious.
For a real test of your rifle, use sandbags, use your sights like this, and use a SQUARE black aiming-point about 4 inches square as an aiming-point, at 100 yards. Just see how tight you can put your shots down there. With called 2-round groups ("hunter" or "sniper" groups, some call them) from a cold barrel, mine will do half an inch.... if you can hold it.