sounds like a bad chamber but a few more specifics would help. Are all reloads and what loads is he using. It kind of sounds like the powder he is using is way to slow and the case is being extracted before pressure has has dropped. this will eventually break the gun. powder needs to be in the 4895, varget burn rate range and depending on what grain bullet he is shooting 150 for example should probably be in the 2700-2800 fps range. 165-175 should probably be in the 2550-2650 range. if you're loading for more velocity than that or heavier bullets in a garand you're asking for trouble eventually. they are great guns but were designed around certain burn rates and bullets for gas/op rod optimzation.