One of the best rifles in Fallout 4 and where to get it by level 15

The overseer guardian is one of the best rifles in the game and you can get it pretty early, even earlier than I did as long as you have the 3 Fusion cores and about 3300 caps. So, save every cap and pre-war money you can find on the way to Vault 81 and you can use 3 fusion cores that have very little charge on them to get into the vault.

Any questions feel free to ask below.