These semi-auto rifles that are being called "assault weapuns-guns" are used in competition target shooting, pest control, defense of businesses and livelihoods. Are they the first weapon that I would choose? NO! but they do have a place on the list of guns to own.
1. 12 ga pump - home self defense, bird hunting, skeet and trap shooting (there are better choices for this one), small game hunting, large game hunting at shorter ranges (there are better choices for this one)
2. .22 rimfire bolt action rifle and revolver. Will generally fire any 22 short, long and long rifle ammo. Great for target shooting and practice, small game hunting, pest control.
3. magnum revolver - defensive carry concealed, hunting medium and non-dangerous game, target practice and competition, defensive carry while "in the field" (fishing, hiking, or hunting)
4. Bolt action rifle - hunting, target practice, competition. Best when it utilizes a standard military cartridge because the ammo is available widely.
5. Semi-auto pistols - more easily concealable for legal carry, higher capacity magazines make them better against small groups of attackers.
6. Semi-auto rifles - particular types of competition require the use of "military" style weapons and the cartridge generally determines the ranges that targets are placed. 308 and 3006 for out to 1000 meters, 6mm for out to 600 meters, .223 (5.56mm) for out to 300 meters.
These rifles are also used to hunt game, control pests and informal target practice.
When dispatching ferral pigs that tear up your land and ruin crops you need a high capacity magazine.