Regarding shooting steel out of your flues, IMHO, that would best be answered by the guys at Doublegun BBS - http://www.doublegunshop.com/forums/ubbthreads.php?ubb=postlist&Board=1&page=1
I'm sure one of the guys there has tried this....and done that....and you'll get a wealth of knowledge about shooting your flues. Let them know how your gun is marked also.
Hope this helps.
D.



























