The barrel thread is a unique system. The barrel back is autococker threads, but the barrel front slips all the way into the barrel back. So its like having a one piece because the front goes all the way to the breach. Check http://www.vangaurdus.com
for additional sizes. I'm new to Vanguards so not exactly sure what to run my reg at, but right now I have my ninja set to around 550 output. I'm hoping thats fine cause I'll be taking it out for the first time this weekend.