[hummingbird]

"Some shotguns are ported to reduce recoil."

Mr. h is schooling me on guns, etc.

But, what does "ported" mean?

I want to provide him with some more information that he didn't tell me first or tell me yet!

HA, HA, HA on Mr. h!

I'll come clean about it...eventually....HA, HA, HA!

[mnehring]

Here you go. This appears to be the type of gun he is using (Browning 425). Look at the end of the barrel, see all the holes. Those are vents to allow some gas to escape to reduce recoil.

[MasterGunner01]

Porting is putting a series of holes [at an angle] in the top of the barrel to direct the propellant gases to reduce felt recoil.

That puff of white smoke close to the muzzle indicates porting [to me]. Porting will also reduce muzzle rise from firing, but it increases the muzzle blast and flash.