Boom Hammer in Bloodborne is a trick weapon used by the Old Hunters which was crafted by the workshop heretics and the Poweder Kegs. To get this powerful weapon, you must be ready to fight against three basic enemies So without any further ado let's get started with the Bloodborne: The old Hunter Guide to retrieve The Boom Hammer.
The Boom Hammer is a combination of the Gaint hammer with the miniature furnace and when you try to ignite the fire it will emit a volley of flames which will explode the nearby enemies and foes. It's not difficult to get this weapon, but a trick one so make sure you don't get lost on the way.
Starting from The Old Hunters area where you fought with the first Boss you nee a path where a bunch of enemies firing some small cannons at you. Try to take them all out and dodge the cannons at the same time to continue with your path. As you move ahead in the same direction you will be attacked by few more enemies by this time they throw Molotovs instead of cannons.
Once you take down all the enemies you will see a blood stream on the right and a house which you need to enter to your left. The House is full of enemies so you better be prepared for what you will be going through. Three Basic enemies are what you show be taking down once you get inside. The trick here is that the house inside is complete dark so that the enemies can easily take you off-guard.
After dealing with the foes head downstairs towards the wheelchair with a dead body on it. There is an item on the floor just in front of the wheelchair and the wheelchair is rigged with explosive so it's better to attack the chair from a distance and avoid getting the damage.
Now that the chair blows up you can easily walk up to the item and collect it. This Item is none other than the Boom Hammer. Congratulation you have made it and to use it with easy try hitting R2 instead of R1 to slam to the ground and turn into a powerful explosion.