Haven't seen anybody use one but don't see anything wrong with it. As you say it will be a little slower with the long travel that an under-lever has but who cares if thats what you have fun shooting with. That being said I have noticed you say it's short-chambered, if it is also a damascus barrel I wouldn't use it unless with BP. There is no rule against using a damascus with smokeless shells and I have saw people use them, but I feel it is irresposible and places the t\o and others in danger.