My new Ballistic Advantage 20" DMR fluted barrel

[bj139]

Yes...definitely through a fully open port. I daresay even more of a loss than with it cycling a bolt carrier. The bolt carrier at least has back pressure that minimizes pressure loss behind the bullet.

How much? I don't know. You're the perfect study case opportunity as it would be easy to rig a temp block in order to measure results.

When you put hand guard on, will exhaust gases impinge upon it?

Anyways, happy hunting

The port is 12" from the breech so the velocity cannot be less than a 12" barrel. The major restriction in the gas system is the port so I don't think there will be much, if any, velocity change.

I have hanguards intalled with no GB and there is only a smoky spot on the inside of the schedule 40 pipe.
Here is a barrel I shot wrapped in camo tape.