Checking the PPU website you will find 30.06 Springfield listed under Sport & Hunting, they also have 30 (7.62 x 63 mm) Ball, M2 listed under Military. Since this ammunition is listed and marketed two ways what may be occurring is the Sport/Hunting 30.06 Springfield is manufactured using a shell that can be utilized for the (8) different types of bullet weight/type as well as the possibility they use a more commercial powder charge.

The Military 30 (7.62 x 63 mm) Ball, M2 is undoubtedly made by contract, over-runs will be bought up and sold as they occur, I have not seen any PPU M2 Ball ammo, just the previously mentioned Springfield. The agent for the Importer may or may not have been properly informed when he responded to the question, the fact that the 30.06 Springfield will not fit (8) rounds indicates a problem that is not widely reported with any other commercial ammo used in a Garandicon with en bloc clips.

Possibly some shooters who use commercial ammo not designed as compatible with M2 in their Garands may shed some additional light on this subject. I've never had a problem with PPU and I've used it in semi-auto handguns as well as my AR, Sig 556 (both 556) and 1918A3 ( 30.06 Springfield). With a sufficient supply of surplus M2 I haven't felt the need to use commercial ammo in my Garands, save for a few hundred Hornady Match rounds.