Don’t know exactly, but it’s not a semiauto (as the OP conjectured) but an over/under.
Browning Citori 725, I think.
ETA: http://naturalgeographic.net/wp/browning-citori-725-awarded-field-stream-best-of-best-award/
Looks like pro-porting. Holes are simply drilled on each side of the upper half of the barrel to form an outline of an inverted slim trapezoid. This shape is similar to the slots made during magna-porting for rifles and handguns but the process is different. Magna-porting uses EDM.
It was actually one of Donald Trump’s farts but that’s for another thread. 
Come on, guys, that smoke is obviously evidence that the photo is fake!
I don’t even need to go look on the interweb to find that some kook has already claimed it was photoshopped. I know it’s out there.
Seek and ye shall find. Not so much the pictures, which are pretty funny, but the comments at the bottom.
Nice.
So far the winner is “What’s up, Barack?”
And of course, the summer greenery is photoshopped in to make it look like an pre-existing photograph. </sarcasm>
It’s clear that even when Barack appears to be focused down the middle, he’s still getting off a shot at the right. Also, in skeet you fire at targets flying up into the air. The fact he’s shooting late and dangerously level, head high, suggests all this is completely new to him and that claims of frequent shooting forays are completely fabricated. </ lots more sarcasm>
Ha, Eutychus’s picture of Barack in the General Sherman had me clamping fist over mouth lest I give away my mirth at work. Hilarious!
I wonder if there’s just a rack of shotguns beside a rack of tennis equipment etc. that’s supplied for the prez and all his guests. I assume Obama and previous occupants didn’t schlep a gun case up there every weekend.
What’s the difference between skeet and trap shooting? I read somewhere that the (angle? weapon?) might indicate trap.
Anyone else get edgy when they noticed that the shotgun looks like it’s been picked up and handled by the barrell all day long?
Four of the last seven presidents were lefties (Obama, Clinton, Bush Senior and Ford.)
That number should be five, but Reagan was a natural lefty forced to go righty as a child in school.
Nope, it just looks like a blued barrel to me. Its purty!!