u can get it after youve returned frm the spire. if you killed giles, it wnt be so easy. but if u helped giles get rid of ripper and his gang, u will notice a big change n brightwood farm. after you do 1 last mission for giles, he will reward you with the key to his cellar. thn just follow ur dog and fight ur way thru afew hollowmen and ur dog will lead u 2 where the weapon is buried.
You should do the quest Cold Comfort Farmer before going to the Spire. Once you return you should do the quest Blind Date. After finishing Blind Date, buy the farm house and move in. Remove the key to the cellar from the closet on the second floor and then rent the property out. The weapon will not appear if you are living there. Next go into the cellar that you find in the barn of the farm. Your dog will lead you to the Dig Spot where you will find the Enforcer rifle.
