When you use your weapons in Red Dead Redemption 2, they slowly lose their efficiency. Some of their stats will slowly drop which heavily affect how well it performs. You can expect Damage, Range and Accuracy to all drop if the weapons condition deteriorates.
Luckily though, you can repair your weapons by cleaning them. This fully restores all of the stats that you might have lost on the weapon too. You will need gun oil to do this though.
Below, we have a quick guide for acquiring gun oil and then cleaning your weapon in Red Dead Redemption. Whilst we have covered a few more guides for the game here.
Repairing Weapons
As I mentioned before, you will need Gun Oil to repair weapons. You can get this by heading to the Gunsmith in town and browsing the catalog. You can find it in the Accessories section for just over a dollar.

Now that you have gun oil, you can repair your weapon. Open up your wheel by holding L1, and hover over your weapon that you want to clean. In the bottom right, you will see ‘Maintain’ by pressing in the right analogue.

You can see the stats of the weapon in the bottom left corner, whilst in the bottom right you can control the weapon. Choose the Clean option to repair it. You will need to do this again multiple times in the future.