easier magazines to get?

[Brother in Arms]

hey everyone I am thinking about building a .45ACP rifle and I was wondering if M3 Grease gun magazines or Thompson magazines where easier to get? Also which are cheaper. Anyone have any sources for these?

Thanks
brother in Arms

 

[Floppy_D]

I see them frequently at gunshows under $15.

 

[MisterPX]

I see more thompson mags for sale than M3 mags. Check out an issue of shotgun news.