Absolutely NOT SO !!!! In over 30 years of shooting the Garand rifle I have NEVER had even one slam-fire, nor have I witnessed any at the many matches I have competed in. I have used all makes of primers as well. The key to not getting a slam-fire is to be damn sure the primers are seated below the case head. At the very least, seated even with the case head. A "high" primer is a prime candidate for a slam-fire however.Slam fires are not uncommon with Garands.
+1 with the non-use of WD40. When the carrier (the liquid) evaporates, what is left behind is a coating that is akin to varnish, or shellac, neither of which you want in or around your firearms.