I don't carry '+1' but I always carry with 1 in the chamber. Load a magazine, insert into gun, rack the slide. So there is one in the chamber but the capacity is not +1, just what the magazine carries (15 rds).
You carry 14 rds. + 1. The + refers to the round in the chamber and isn't negated by downloading your 15 rd. mag. by one.
The M1 Rifle uses "clips" to hold the ammo togther so it can be inserted into the magazine of the rifle. Our semi-autos don't take clips. They take detachable magazines.
In Israel, they carry their guns unloaded. Here, we don't.
Someone once pointed out that a terrorist attack happening around you doesn't require, perhaps, as much quick access to a gun as a criminal attack we're more likley to experience here in the US. Personally, I think the Israelis recognize the need to be armed (on the one hand), but they're a paranoid (on the other). Even their secret service equivilent carrys chamber unloaded, but they're very well trained to draw, rack and shoot.
For you and me, the unloaded (chamber empty) gun puts us in more danger. It means we may not be able to deploy it, or that we'll be fumbling around trying to get it loaded. A while back, I saw a video of a man getting killed when he attempted to draw his gun and rack the slide. He didn't make it. He was executed at close range by the 3 thugs who came in suddenly. There WAS time to draw and shoot. But not to draw and fumble and then have to do it again. His draw wasn't very smooth, either.
As he drew his weapon, the bad guys didn't pee their pants and head back out the door. They closed quickly and shot him as he AGAIN tried to rack the slide. Video might have been on this site, but I'm not sure. If you want to carry your gun unloaded, good luck.
OK, I'm in a finniky mood today. Had a root canal and the pain meds seem to have put me in an instructional frame of mind with respect to technicalities.