Hey folks,
I have had a Lyman 150 grain Loverin gas check design double cavity bullet mould for thirty plus years, and it has worked well in every .30 cal rifle I have ever tried it, including my three M1 Garands. I size the bullets to .309 for regular .30 cal stuff, and I even get good results when lubed in a .311 sizer die and used in the SKS 7.62X39 cartridge. Come to think of it, I did try the same .311 in an AK-47, and it did not do very well in it. Then again, neither did Russian jacketed bullets, so maybe the AK is not a good choice for consideration.
In any case, yes, gas checked cast bullets can be used very effectively in the Garand, and I recommend the Loverin design.
Best wishes,
Dave Wile