My nephew recently purchased a rifle in ,45-60 caliber. He is looking for a source of brass with the proper rim thickness. While .45-70 brass can be used the rim is just a little bit to thick. Closing the bolt is difficult. Is there an inexpensive source for correct brass out there some where? What is the source. He wanted a unique rifle for his cowboy shooting activities and he got one. The problem now is feeding it. Thanks for any help you can give.