Throughout all of Cyberpunk 2077's many technically advanced and traditional weapons players can find, sniper rifles are some of the best options. These weapons fulfil exactly what you'd expect from them and allow players to pick off enemies from a distance with precise shots that cater to stealthier builds. Sniper rifles won't always fit into everyone's playstyle, but if you're going to pick one to have in your arsenal, it should be the O'Five.
This O'Five sniper rifle benefits from being an Iconic Weapon which means that's very powerful to start with and can be upgraded to higher rarities to make sure it's viable throughout your playthrough. To get the weapon, you have to first unlock the Beat on the Brat: Champion of Arroyo quest that you get after talking to Coach Fred, the NPC who's near a sparring bot in your apartment building. Get the quests from him and beat the first Beat on the Brat challenge to make sure you're accustomed to the brawls and then head to the map marker in Arroyo for your next fight.
Once you arrive, you'll find Buck, the champion for that region. You'll banter a bit about who everyone thinks will win until you get the option to comment on his sniper rifle sitting near him. I had to have 10 points in my Body attribute to unlock the dialogue option, but if you're already pursuing brawls like these, you've likely attained at least that many Body points yourself.
After talking about the rifle, you can raise the stakes to take the gun if you win the fight, but you'll have to put $12,000 eddies on the line for him to accept. Once you win, he'll have his friends attack you. Take care of them and there will be nobody left to stop you from picking up the weapon.
So, why the fuss over the O'Five in the first place? Besides being outfitted with a powerful scope that easily highlights enemies, this weapon adds explosive tips to your sniper rifle ammunition. Assuming you're keeping your weapon upgraded to keep it viable, this means that any decent shot on an enemy will blow them away while dealing splash damage to those around them. It's nowhere near as stealthy because of this, but it makes up for it in damage.
A few caveats about the O'Five to keep in mind is that you'll need to invest a lot of points in the Crafting tree to upgrade it from the Epic to Legendary tier, so start on that early if you plan on keeping it with you for a long time. The splash damage from the explosive rounds can also affect neutral NPCs nearby your enemies, so be careful using it in crowded areas or in NCPD hustles where noncombatants are involved.
If the O'Five isn't enough for your explosive arsenal, consider looking for the Comrade's Hammer weapon as well. It too packs an explosive punch at the cost of having to reload after every shot, but you'll find that one shot is all you really need.