I just got my 4 inch 10mm thick General Leathercraft belt in the mail today and the first thing I noticed was that I went with the wrong size. I was in between an L and XL and went with the XL. Anyone have any experience with this and punching new holes in the belt? I really don’t want to order a new one. I plan on losing weight so this could be an issue.
I would just take it to a cobbler or something. They’ll do a good job and it won’t take long/be expensive
Yep, my local cobbler does it for me. It’s super fast and easy, so he also doesn’t charge me for it. Just flash a really big smile. 
A good sharp drill bit would get the job done. You could also buy a leather punch from a place like Tandy
Have you shot the Pioneer guys a note and asked them about swapping it or cutting it down?
I also suggest talking to Pioneer, they’re a good company. If it’s a standard size I bet they’ll swap it for you. They also do custom sizing. I got a lever belt from them that’s a custom length and width, they were excellent to work with on making it too.