I have been using bolt action arms from the various infantry sprues for conversions - they're immensely useful!
What I've found is that the sizes of arms and hands are not actually consistent. The Blitzkrieg German infantry arms work for larger figures, mostly men, whereas the regular British infantry are better for smaller models, mostly women (funny enough the British heads are larger than the German heads). Those are the main two I have, besides a couple weapon sprues which don't really give me a good indication.
As I need more arms and am fishing around for spares, I'm trying to figure out what alternatives are in similar sizes and what other infantry sprues I could try to obtain spares from. Could anyone compare the arms from various nations? Regular Germans vs Blitzkrieg, Russians, Americans, and so forth?