FMJ and LRN down the same barrel

[Gatorade]

I guess this would be in the reloading section because it is a question about bullets. Talking to Matt earlier about some reloading I was doing for my range trip this weekend and mentioned I was loading some of my cast lead .45 bullets for the Rock Island 1911. He said that lead isn't too good in 1911s. I have thought lead would not be reccomended in anything with a gas port because shavings could block the port. However 1911 is a straight barrel. I know some say switching back and forth could lead to some lead, and copper fouling layering on top of each other but what about just lead?