Head: Power Force Elite World Peacekeepers
Torso: Tunnel Rat v4 (modified)
Upper Arms/Legs: Dart v1
Lower Arms: Shipwreck v6
Waist: Salvo v1

Knife: Dart v1
Chest Mounted Gun: Tunnel Rat v4 armour with modified power pack from Dr Mindbender v1, modified arm guns from BAT v9 and the ammo belt and a radio and wire from a Chap Mei soldier
Backpack: Duke v9 modified with an ammo box from a Chap Mei Soldier

The fourth of my Real American Hero mini-project, Double Blast presented a real problem, as the original figure was so similar to Roadblock. In the end, I went with the helmeted head, as it seemed to give sense of difference to the original (yes, Roadblock did come with a helmet, but the standard image of him is never seen wearing it). The main difference for me was to devise a heavy machine gun for him to carry. I slapped a few parts together, and it looks extremely unrealistic, but fun, even if it is somewhat redolent of the original Heavy Duty.