First off, YOU don't want to take our guns. Your politicians would completely throw the 2nd amendment out today if they could. This is why Biden hired BootyJudge as some type of gun Czar.
Second off, AR-15's are NOT designed to kill large numbers of people quickly. They are rarely used in mass shootings. They fire either a .223 or a NATO 5.56x45mm round. This is the same round that the military uses in the M-14 rifles. The reason for such a small round is so that more soldiers will just get wounded rather than die. Most hunting rifles shoot larger rounds because a .223 or 5.56, unless the hunter is a dead accurate shot, will wound the deer. The larger the animal the less effective that round is. Caliber is in inches diameter. So a .223's diameter is only .003 of an inch larger than a .22, a kids gun round. However the .223 is in a larger cartridge with more gun powder making it fire at a higher velocity.
There is nothing special about the AR-15 that makes it fire any faster or more accurate or with higher power. The only thing an AR-15 does is make leftists wet their pants when they see one. I guess black guns are scary or something.
It was never used in the military nor was it ever designed for the military. The AR-15 is NOT fully automatic and never was. It is semi-automatic meaning 1 bullet per trigger pull. There are a ton of hunting rifles that are also semi-automatic and fire a larger round.
There is not a single gun sold commercially that does not require a background check. All firearms must be sold by an FFL (Federal Firearm License) holder. The FFL holder must perform a background check. This includes gun shows. Don't listen to Democrat politicians and pundits. They lie ALL THE TIME about guns.
What does it matter to you what anyone would do with any weapon or anything else, including a machine gun? When you start passing laws based on what you think other people need or do not need then freedom is over. Never ever question what other people need or don't need. That is none of your business.
The people who purchase guns legally are by a huge number (99%) not the ones who kill people despite what the left preaches. The left lies. In this country gun are used 3.6 times more to prevent crime than to commit crime. And that number is low because those are just reported gun usages. Many times a person will draw their weapon and the bad guy just runs away. No shots were fired and no reports get filed for most of those.