Most of the older Handbook equipment converts pretty directly to AToW. The Life Paths are defunct (AToW uses generic Life Modules instead, to avoid power creep), but the weapons and critters work about the same way, since the stats between MW3rd/CBTRPG and AToW use the same scales. The old MW3rd/CBTRPG damage values for critter attacks and weapons convert directly at 1:1 for AP, and 1D6:1 point for BD, so a critter that attacks for 2*4D6 in MW3rd becomes AP/BD: 2/4 in AToW, while a weapon that delivers 5*3D6 damage in MW3rd becomes 5/3 in AToW.
I should point out, by the way, that the equipment list in AToW provides the converted stats to ALL personal weapons and equipment featured in the MW3rd/CBTRPG, Combat Equipment, and the House Handbooks as of the time of its publication.
So, for the most part, having all the House Handbooks and the AToW core rules will cover about everything for you.
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