I'm just saying that if you ban guns, people will acquire guns illegally or use knives and other bladed weapons. If you ban knives and other bladed weapons (which is basically impossible without constant frisking on the streets) people will use blunt objects and so on and so forth.
You will be gradually making it harder and harder for criminals to hurt, rob or kill people, which reduces crime considerably, but it won't get rid of the criminals completely, and will make life much harder for people who use guns and bladed objects responsibly. In the case of the UK our olympic handgun shooting team has to go and train in Switzerland because all handguns are completely illegal in this country (save for black powder pistols), yet you still get handgun shootings from people who have recomissioned decomissioned guns or bought their guns illegally. They are rarer, but still common enough to be a problem. In this country, if you carry a small pocket knife for use as a farmer, you will be arrested and charged for carrying such a weapon - even letting the police know you are carrying it or that you accidentally left it in your pocket and you just want them to know, then handing it over - can get you arrested.
And furthermore, despite our ban on all automatic weapons, all military grade semi automatic weapons, all handguns, we still have shooters like Derek Bird who manage to go on killing sprees - killing 13 and injuring 11 - using purely legal weaponry. As soon as people like Mr. Hamilton shot up that school in Dunblane with his pistols, people were asking to ban handguns, but they weren't asking the question "How the flying fuck did a guy that obviously mentally unstable with a history of sexual offense against children get those guns?" The answer is regulating "who gets the guns" more effectively, not banning the guns themselves.