30 caliber bolt action
Berea Lever Action
Magnatic Vertex Rollerball
All of these are single barrels and easy to make. Don't sell yourself short..... There can be great margins in all these pens. People do not mind paying for quality (the pen and the turning). Stay away from the Chinese knock offs. Check out exoticblanks.com Great people, ship fast, great fill rate on your order, mix & match discounts, and a free bag of M&M's with every order! Good luck!