Speaks fluently supersonic and subsonic - also at the same time.

The HK437 is available in 7 and 9 inch barrel lengths. With the appropriate gas adjustment, the HK437 can fire both supersonic and subsonic ammunition in mixed mode. The weapon shares the operating concept of the HK433. There is a choice of the push-button operating mode for users trained on HK416/AR-15 systems as well as paddle operating for trained G36/MP5 users.