I have an early TC Cherokee .45 with a 3/4" barrel. Your 13/16" in 50 cal would be fine, considering, of course, appropriate powder charges. 80gr-3fg is max in my .45! Problem: what happens down the road when your guns future owner overloads this rifle, he bought, at your estate sale? Just say'in. I've taken a 50cal. cva barrel, bored it out to 54/28ga smoothbore, then octagon to round, and produced a fine shooter. APPROPRIATE POWDER CHARGES, required!!! Not lawyer proof!!