Advice on NOT screwing up getting the legendary Bodycount assault rifle, please.

[Jurassic Fart 1]

I've made a couple of dismally unsuccessful attempts to get the legendary Bodycount assault rifle. I couldn't find the [Redacted] quest given by Lieutenant Ford during the first complete playthrough, nor was I able to during the second, which I dropped to start a third. I might have killed Lieutenant Ford during the second playthrough but failed to pick up the collectible that gives the mission, and returning later to the scene, the collectible had evaporated, effectively locking the weapon's procurement, hence starting a third playthrough.

Most say that you can't get the gun until you complete the storyline, but some say you can get it earlier. I don't want to screw it up this time. I need to find Lieutenant Ford and not eff up picking up the quest. This time, I want to avoid going into Lieutenant Ford's tent until I can actually kill him and pick up the necessary goodie. Any advice would be helpful.

[XeRnUno]

Most of the L&F and named KEY quest are available, when the endmonster spawned into the game.

Example:
Garden Eddy, Nicci Pricekey have a Butcher as enemy. Means they will spawn after you killed your 1st butcher at the peer. Main quest story line.

REDACTED also has a Butcher as final enemy. So Lt. Ford will spawn as soon as you finished the peer mission.

[Jurassic Fart 1]

Found out the hard way after many tries that the only way LT Ford will spawn is after completing the storyline; no other "advertised" methods work. Maybe they once did, but that was evidently patched out.