Chris Cartaya's Merlynn barrel is either a quantum leap in high-precision Nerfing, or complete baloney. Either way, these stencils make them infinitely easier to build.
The Merlynn is a brass barrel with a helical insert nested within. Theoretically, the helix acts as a SCAR, imparting spin and relieving excess pressure without the need for a long, heavy muzzle device.
Simply slip the Stencyll over your brass, stick a pen or scriber through the slots and trace the outline, and cut with a Dremel. This pack includes Stencyll sets for 9/16" and 17/32" OD brass tubing.
Three different twists are available - select one for your Merlynn.
1:16 is a gentle twist rate for low- to mid-power blasters, with rifling similar to a SCAR. This is the ideal choice for most blasters.
1:12 is an aggressive twist for high-powered blasters. The rapid spin is immediately noticeable and has a prominent effect on blasters that normally rip through SCAR's.
1:8 is an extremely aggressive twist for serious modders. The barrel must be lined with Teflon using dry lube or Chris' favorite, Pledge, to limit how much speed is lost to friction. A muzzle velocity of 300FPS or higher is recommended to get the full effect. This will shred foam and make all your darts single-use.
Watch Chris' assembly video and marvel at his pineapple shirt: https://www.youtube.com/watch?v=t1P3rzDao3k