A revolver can be dropped from dead enemies or possibly bought at weapon shops (the weapons sold at weapon shops are random and keep changing so there is no set shop location to buy one).Be on the lookout for revolvers dropped from dead enemies.
I found my first revolver from a dead enemy in the Pacifica region while I was doing a story mission there.This is an example of what a revolver looks like in your inventory:Method:
Once you have a revolver, find a group of enemies in a open area (story missions, side missions, around the open world or police) and kill the majority of them so that there are just 1 - 3 alive. Move away and take cover from them so that there is a little bit of a distance between you and the enemies. Keep waiting from behind cover but keeping an eye on what they are doing. One of them should throw a grenade at you after a while. You must then shoot it in midair with your revolver so it explodes in midair before reaching you.
If you keep a distance from the enemies and just keep waiting, they should throw grenades at you every so often. It seems enemies have an unlimited amount of grenades.
It also does not matter what type of grenade the enemy throws at you.
You can make a manual save before attempting this at a location (for example in a story mission) so that if you fail you can reload and try again.This is a video of how it is done:I unlocked this achievement with an enemy in a story mission using a “DR5 NOVA” Power Revolver that another enemy had dropped in that same story mission.
If you are having trouble shooting the grenade in midair you can purchase the “Dynalar Sandevistan MK. 1
” operating system which costs $7500 from the western most Ripperdoc in Northside, Watson. To equip this item, you need 6 Reflexes.
* Dynalar Sandevistan MK. 1 slows time by 50% for 8 sec. (Cooldown 30 sec.). Increases any damage dealt by 5 percent when Sandevistan is active. Activated by holding .
When you see an enemy starting to throw a grenade you can use this to slow down time so it will be easier to shoot the grenade midair.