How can I get La Longue Carabine from Corporal Sterling in Fallout NV?

The only way to get the rifle is by killing Corporal Sterling and looting his corpse.

The best ways to do this without angering the NCR is to use the "Sandman" perk, or get a silenced sniper rifle and shoot him in the head from a position where you can not be seen.

If you don't want to kill him but don't care about losing a slight bit of rep with NCR, you can try and shoot the gun out of his hands then pick it up. If you do this and travel away from the airport (or Camp Hope, depends on where he got sent) and wait three in-game days, they've forgotten you and everything is back to normal.

I stole all his ammo for it & fast-traveled then came back. (as stated above) Then I pickpocketed it from him and fast-traveled away from the area before he could take it back. Just as someone else stated above, wait 3 in-game days, so the tensions will have cooled down. I hate how Sterling's Perception is so high, you can't just pickpocket it from him without getting caught. I tried multiple times (at least 30) and got caught every time. It would be just much easier to kill him or shoot it out of his hand and then high-tail it out of there. Any of those 3 methods will work. So just choose the one that fits your play style and is easiest for you.

No Negative Karma. No significant NCR loss. Sterling still alive. Clean digital conscience!

• Wait until he is sleeping.
• Talk to him. This will allow you some time to get away from him before he talks to you, lead him to the front gate because he will not stop following until he says howdy.
• Wait until he turns around after the conversation, sneak, (stealth boy almost certainly necessary) -SAVE-
• Sneak Critical his weapon. (May take some tries)
• He'll draw. Shoot the weapon from his hands. (A few tries here too, may be wise to save again after landing the sneak critical on his weapon with a 4570. After which you should be able to holster your weapon and he should put his down as well. Orris in Freeside has a hunting revolver. You must disarm Sterling while he is holding weapon or it seems to disappear.) After shooting the weapon from his hands he will follow you out of Camp McCarran, and the ends of the earth.
• Grab it.
• Exit.
• He'll follow, but the entire NCR won't be shooting at you, and you can outdistance him pretty quickly if you holster you weapon, allowing you to fast travel to a repair shop. Because it will be broken.

If you're playing on PC:

I killed him with console commands (open console, click cprl sterling, type "kill") looted his gun, then resurrected him (open console, click sterlings corpse, type "resurrect") and he came back to life, and still had his gun. This could also be a way to duplicate la lounge carabine, because he comes back to life with the rifle on his back! :D

There's a way to get him to give it to you if you do certain things first. After you waste Cook Cook and help Betty with her trauma Sterling walks up and gives the rifle to you as a reward.

I did it years ago via a post someone made but that has become hard to find because of all the players who would rather kill or rob him.

I have a method that may sound good to anyone who doesn't want to kill the corporal or leave him without his favorite weapon.

Open the console by default it's the tilde key (~) click on the corporal and type showinventory. It will then list everything he has along with the item IDs. Find the carbine in the list, type player.additem (the carbine's ###) 1