180 gr. through Garand
I always used PMC .30-'06 150-grain FMJ (3006C) or JSP (3006A) in my M1, as they were loaded to exact Garand specs, and had no problems. I've got some of it left, but I too was faced with this problem. I checked with Winchester, Federal, and Remington regarding their 150-gr. hunting ammo and was told that they would not recommend using it in the M1, but they would not identify the burning rate of the powder.
Subsequently I checked with retired USMC master armourer Gus Fisher, who is revered in the National Match circles in the USA. He told me that the Federal American Eagle 150-gr. FMJ was ok, and that's what I will use when my PMC runs out. PMC is no longer produced. Another choice he recommended was Federal Premium Gold Medal 168-gr. FMJ boattail, which was loaded by Federal to Garand specs. I have tried that ammo and it is great, but at twice the price of the American Eagle.
The above-mentioned ammo choices are the only ones I will use in my M1. Remington UMC and Winchester white box have similar ballistics, but they weren't given Gus's stamp of approval and so I don't trust them. I don't reload.
Hope this helps. Gus often posts on
www.jouster.com in the Garand/M14 area, and is great at answering questions. One day I hope to go to Camp Perry and meet him. Garands and parts are hard to find now in Canada, and I have a Remington 700 for shooting 180-gr. hunting ammo.