I'm working on a project to have CNC hop ups made for TM 5-7s to alleviate the issues created by running propane and green gas. Head over to ASF to learn more:
http://www.airsoftforum.com/board/Fi...#entry18739852
If anyone is interested, please let me know. Material will be 7075 T6 Aluminum, anodized may be an option, and will have 5.7x28 in the appropriate place. If anyone has access to a CNC machine, shoot me a pm.