Where can I get this paintball gun part?

You're not likely going to find that part new. The markers that it came on haven't been made for quite a few years. You can try contacting Spyder direct a href="http://www.spyder.tv/section/contact_us/index.html" rel="nofollow"http://www.spyder.tv/section/contact_us/…/a Another option would be to check out Buy/Sell/Trade sections of paintball websites like pbnation.com. Someone could be selling off the part you need.