Did barrel on my lathe, everything else was cut with a circular saw, shaped roughly with a grinder, hand shaped with rasp then sanded in, shit green paint to hide crimes , and yes I have shot slugs in it, it’s like high fiving a power line.

I have a .22 barrel im trying to prep to put in a build, how can i ream it so i can insert the round. I tried to use a 15/64 inch bit and a jig(3d printed) but that dident seem to do much. What is the cheapest and easiest way to ream m barrel?