what ıs the best gun to be able to shoot from 3 km?

BY shoot I suppose you mean be able to hit something at that distance. Normal hunting cartridges like the .270 and .30-06 will shoot that far, but not accurately.

Your only chance of hitting something at that distance would be with a .50 BMG rifle, or perhaps one in the new .408 CheyTac.

The longest recorded sniper kill ever was 2.43 km (2,567 yards) with a McMillan rifle in .50 BMG.

3 km? Are you sure you are using the correct distance? If you have your distance correct, the only shoulder mountable gun capable of shooting that far and hitting anything would be the .50 BMG. Even so, it would have to be fired from a solid rest. Other than that, you would have to move up into artillery pieces.

I have a question, why in the heck would anybody want to shoot at a target that is 3 km away?

Nothing that you could shoulder. Right now the world record for a sniper kill is slightly in excess of 2500 meters and that was made by a canadian sniper in Afghanistan about 3 or more years ago.

His record superseded that made by American Sniper Carlos Hathcock in Vietnam.

Carlos Hathcock mounted a 3x9 on a .50 caliber machine gun and made a kill that way at 2500 yards 109 yards per 100 meter, you do the math.

The canadian was using a .50 caliber sniper rifle. either way your between 700 to 500 meters short even if you have the training, and experience.

The last I heard, to fire any normal gun you have to be close enough to put your finger on the trigger. I don't see how you or anyone else can do that "from 3 km."

It would be very intresting to watch you fire any gun from 3 KM.

The way you worded your question & If my math is even close to being correct, that means that when you fired the weapon, you would be about 1.8 miles from the trigger of this gun.

I don't believe that your arms are that long.

Your not hunting at 3 km. The only rifle close to that range would be a 50 BMG.

Or you could call in a artillery attack.

Nothing. .50 cals are not the longest shooting rifles anymore either. A .338 lapua has almost the same tragectory as them. .408 cheytac and .416 are just as good if not better for long range. When you get into rifles like that the main limitation of the rifle is the shooter. There is no cartridge that can be reliable at that range that I know of. Just strafe it with a GAU 8A.

A BMG 50.cal, okay it might be a little on the big side, but it can shoot farther than 3km that's for sure. Other wise try a 300 magnum or 30-30, or 30-06 or maybe any 223.caliber gun, AR15, M16 or a mini-14.

Hope that helps.

take care and have a geat new year....cya....

M252 81 mm mortar is about as close as you'll get. Be serious.

50 caliber sniper