Actually it is the opposite Mark. The burn rate is too slow. This causes the port pressure to be to high at the gas port, overdriving and possibly bending the op-rod.

I would use no heavier than a 165 and no slower a powder than IMR 4320.

you will be fine with factory, the rule of thumb is don't use anything over 165 grn bullet weight. for reloads, use IMR 4895 or IMR 4064 and 150 or 165 grn pills. you can easily and safely for the garand get over 2400 fps. don't have my data on hand....so double check but i believe between 45 and 48 grns of the 4895 with a 150 grn bullet will do well for ya.

proper burn rate and pressure is the ticket to make the gas system work well and aviod damage to the opp rod.