Opforce have sent in details of their new M249 drop in kit and also advanced warning of their summer sale:
Hi, We now have our M249 GBB Drop In Kit on sale now for just 399us. This summer sale will last until the end of July. The M249 GBB Drop In Kit is the first and only to be made with nickel plated steel internals. All fine parts are machined with the highest quality. Using your aeg mag. We have adjustable fps, rof, recoil, and hop up. With a take away front barrel assembly.
This system can be run in freezing weather with no cool down effect due to the nitrogen/hpa gas or co2. We have the hardest hitting recoil system. All pieces come with a warrantee.