Space Marine Honor Guard models come with power weapons in their wargear. they have an option that says "any model may take a relic blade for 15 points". (a relic blade is S: Always 6, I: User, AP: 3, and can NEVER benefit from the +1 attack from having 2 weapons)
notice that it doesnt replace the power weapon
honor guards also have boltguns AND bolt pistols
so now i have honor guards with boltguns, bolt pistols, power weapons, AND relic blades.
in 5th ed this wasnt a problem because in assault i could choose to make 2 attacks at strength 6 or 3 attacks at strength 4 (power weapon and bolt pistol)
the models are holding axes, but a relic blade and power weapon look identical
so what kind of power weapons are my honor guards carrying? it actually matters in 6th ed