10+1 means the mag's maximum capacity is 10 rounds, and the 1 means 1 round in the chamber. You should not load 11 in the gun. Load 1 round, eject the mag, and load it up with 10 rounds and reinsert.
There were historical reasons for the 28 rounds in the AR mag - mainly early springs were not very good, but that's a thing of the past. The only sound reason to download an AR mag is to make tactical reloads easier to push the mag into the well as the spring isn't maxed out.
There is no reason to download a pistol magazine, ever. If it doesn't run properly loaded up, it should be replaced.
There were historical reasons for the 28 rounds in the AR mag - mainly early springs were not very good, but that's a thing of the past. The only sound reason to download an AR mag is to make tactical reloads easier to push the mag into the well as the spring isn't maxed out.
There is no reason to download a pistol magazine, ever. If it doesn't run properly loaded up, it should be replaced.
