Mounts, Barding and Encumbrance Questions

How much does barding weigh? The same as regular armor? 1 stone per AC pt?
Should mounts not trained for war be capable of wearing it?
How do you calculate the rider’s weight in stone? Do you guesstimate it? Let the PC make it up? Roll for it? Etc.

I rule people weigh STR+0.5*CON stone rounded down unless the PC is fat. I reason the advantage of being weak and frail is you’re probably built like a stick so if someone has to carry your paralyzed ass out of a dungeon they can do it without losing movement rate :wink:

Barding weighs 1 stone per AC. Mounts not trained for war can wear barding, but they fight as 0th level monsters when doing so because they are so uncomfortable and chafing. [Wow, the circumstances that arise in campaign play are hilarious.]
You calculate a rider’s weight in stone by dividing his weight by ~ 12. You can adjust that up or down in your judgment. For example, a grotesquely fat 250lb man is going to encumber a horse more than a ripplingly muscled 250lb man, because the latter will be supporting himself better with posture, leg muscles, and so on. I might make the obese man weigh 25 stone and the muscle-man weigh 18 stone (250/10 and 250/14 respectively).