It seems we players aren't supposed to abuse enclave to get that item so here's so ideas how it could be obtained.
- It spawns in energy weapons shops
- It can be looted from rotma, suggested by mcdoctor I think
- A similar quest as slave run, but without cooldown:
You go talk to BoS guy at any town. High tier gear is requirement, no cha requirement. Ask for job as mercenary. He will say the usual
"Hurr, you look like someone who can manage himself, blabla. We need help from some non-Bos guy to do shitjob for us"
Your job will be to raid an enclave outpost and steal intelligence accompanied by an npc mercenary band.
It's small outpost with some enclave initiatives with random enclave gear plus one actual guy in APA. There's some lockers with random good loot such as drugs, mfc, plasma pistols, gatling laser or avenger. Either one is guaranteed. You can bring friends there, but they too need to have top tier gear. If you die, your stuff is lost but you can repeat the quest as much as you want.
Another way:
- Enclave has crooked quartermaster and you can bring him supplies and buy top tier weapons. He's total weirdo and wants things like beer, booze, prewar food, nuka cola, cigs, drugs. Everything the enclave doesn't have.
- Vault-raid quest by enclave. You are set to raid a vault, take out hostilities and subjugate the weak inhibitants for the enclave to experiment on. Accompanied with few enclave initiatives you must defeat guardian robots (robot dogs, mr handies and the big mean robots), vault security troops (wearing CA, good guns) and kill the overseer. Reward is either drugs, caps, good weapons (gatling) or armor. If you die, mission failed and gear is lost. Repeatable.