If I had a Walker, I think the first thing I'd do would be to adapt a Dragoon rammer to it, or "create" a Dragoon or 1860/1851 etc. rammer for it. Would not be hard to do. But still, I'd take the Dragoon over the Walker, because if the extra powder capacity and barrel length was really an advantage to me, then maybe what I really needed was a short artillery carbine or Musketoon.
As pointed out, even the Dragoon is not ideal for belt carry, but if it was one's only weapon when out in the field, (not packing a rifle or shotgun) you weren't a little guy, and you had a good wide pistol belt, and a over-the-shoulder strap connected to the pistol belt, I think it would be doable. Maybe even a suspender kind of rig for it, kind of like a LBE belt and suspenders.
As mentioned before, all the C&B revolvers will drop the rammer if the charge is heavy, latch spring is weak, and the angles wrong or not deep enough. I believe all the Walkers will drop the rammer....period.