WYSHTECH Airsoft shows the the transformation of a stock CYMA M14 airsoft rifle into a high-performance Designated Marksman Rifle (DMR), aiming to achieve 2.0 Joules of muzzle energy using heavy 0.40g BBs for superior range and accuracy. Key upgrades include a WYSHTECH JVan M14 gear set, a silent piston head fitted with a 37g weight kit to handle the heavy ammunition, and the installation of a new PERUN M14 Electronic Trigger Unit (ETU) to enable features like precise pre-cocking.

To accommodate the high-performance components, they performed several custom modifications to the rifle's gearbox. This involved enlarging the bearing holes from 7mm to 8mm, fine-tuning the tappet plate and nozzle for smoother articulation, and shortening the inner barrel to optimize the air volume ratio. These detailed adjustments resulted in an exceptionally smooth and quiet operation that was confirmed during initial function tests.

During the testing phase, the DMR consistently chronoed just under the target 2.0 Joules, but a mid-cap misfeeding issue was discovered. This was resolved by installing a delayer chip, which was specifically timed to optimize BB seating in the chamber. The final range test demonstrated the success of the build, showing that the completed rifle was "ridiculously accurate" at a distance of 153 feet.