Shields have some sort if Impact number built in but I don't know what it is. They only show Durability stat.

All I know is I've seen my Manslayer Chain Axe last longer banging on shields than that Fist did.

Yeah but you clearly don't break a shield by using the impact stat otherwise it would never break vs ranged weapons.

Besides, you won't break you melee weapons against a shield if you use strong attacks. Which make shields extremely good at dueling powerfists since their strong attacks are so slow they're basically non-lethal.

I'm not asking about if Impact can damage Shields.

What I was wondering is if Shields 'reflect' my impact onto my melee weapon whenever I hit them. As in when I hit a shield, does my melee weapon take a flat amount of durability damage or is my own Impact factored against me?

I know spamming FAs with a klaw vs a shield with break the Klaw. If you mix an HA up in there though you can drain the shield before your klaw breaks.