I read in an earlier post that a Space Marine using a Claymore would get 3xSB instead of a Chainsword's 2xSB added to his damage. Is this true and where is it listed? I cannot find, though I have tried.

Thanx

This is not in the RAW or the Errata; they may have one in First Founding but I've not seen that book.

Sounds like a house rule to make two handed weapons more powerful to me. As per RAW, two handed weapons cover the fact that they're being used in two hands in their damage profile. See that the Sacris Claymore does 2d10 as opposed to 1d10 of a normal single handed weapon, and the Power Claymore does 1d10+11 (+5 over a power sword and +3 over a power axe). Also note that for game balance, two handed weapons tend to pick up other traits, such as unbalanced or unweildy to offset the increase in damage. In the case of the claymore it gets unweildy and devestating (1).

Note that the Chainsword does not give a user 2xSB added to damage. As a Space Marine, you have Unnatural Strength. This means your Strength Bonus is double what it would be ordinarily, meaning with a Strength Characteristic of 45, your Strength Bonus would be 8 (4x2) - outside of power armor. You would then apply this strength bonus to *all* melee attacks, as that is for all intents and purposes your strength bonus.

Power Fists will give you your increase to Unnatural Strength you're talking about. The Power Fist's profile contains a special rule that allows you to add one to your unnatural strength rating (marines have US of 2, meaning the fist increases that to 3 for purposes of calculating damage).