The military is developing an improved version of the M4 Carbine with a heavier profile barrel to allow a higher rate of sustained fire in emergency situations like, for example, the Battle of Wanat where M4 Carbines began failing after long periods of sustained fire. According to The Ground Precautionary Message ACALA #97-031, the M16 and M4 Carbine can only sustain 12-15 rounds per minute over long periods of time. A heavy barrel will help, but that will not prevent the Carbine’s gas tube from overheating and eventually bursting, leaving the rifle unable to cycle its action. The video below demonstrates …

The Armor Development Group, a military and law enforcement research and product development organization, has developed an insulated gas tube for the M4 Carbine to keep barrel heat away from it. Judging from the thermal photos they sent us, it is very effective …

We will be testing the prototype in the near future and will report back.