Volume is useful, but it doesn't really tell you how load capable a pack is. All of our packs are engineered for load carriage and will safely and comfortably carry much more than their volume suggests. Chassis capacity is how much you can load onto a pack in a pinch and expect it to still be functional. It's a representation of what is possible, not what you should be doing.
Our haulers (the Ute and qui-Ya) have a chassis capacity of 300lbs. We know this because we've done it. However, there are very few people in this world who should be carrying much more than 80lbs in a pack, particularly over broken terrain.
Our smallest pack (the Tarahumara) has a chassis capacity of 50lbs. Does this mean it makes a good overnight pack? Of course not. Other packs in our lineup are far better suited for that role. But, like most of our packs, the Tarahumara has a useful and robust compression system that will let you add a lot of volume to it if necessary.
So if you're out on a hike and find a stash of Spanish gold bullion in some desert canyon, don't hesitate to load that pack up with a few bars to take home. You know you'll never find the stash again so count yourself as fortunate that your pack can carry a lot more weight than you would normally want it to.