Not sure if the bore diameters are the same. However, even if you could chamber and shoot the 45 Colt in a smooth bore .410 barrel I would expect horrendous accuracy. Rifling is required to impart spin on the bullet in order to stabilize it. It would be like throwing a football without a spiral. Why not shoot .410 gage shotgun slugs if you want to throw one big lump of lead? By the way, shotgun slugs work because they are made with "rifling" on them that imparts the spin.