Etoh - you're making a very simple concept way too complicated. I already explained it for you, it is not any more complex than that.
A muzzle brake works the same way as the sail on a sailboat. Mass and speed of the air (wind) against the area of the sail.
Sorry but your explanation is inadequate. the sail is affected by a continual stream of force, called thrust, there is no thrust component in this model
as you show no negative vector how about a negative scalar in the model. (decrease in gun recoil velocity) any amount is solely do to a subtraction of the ejecta amount.
any effect on baffles is do to (in most cases) the supersonic shock wave front hitting it, and while it has an impulse their is no thrust component. Thats why they are "louder" on the sides.
Take the case of "porting" recoil reduction with no baffles. MagnaPorting, shotgun porting, any baffle is the rear of the bullet or wad. And in particular when the ports are on the top of the barrel.
Do flash suppressors work with a solid bottom as muzzle breaks (intentional use), yes, by re-directing the gas/ejecta they change the torque moment, and effect muzzle flip, but no baffles are involved, simply an arithmetic subtraction of some of the ejecta.
In most cases adding front wt. on the end of the barrel has more effect than "relying on gas re-direction (breaking)"
