After Hoover Dam, the leaderless Powder Gangers at the Correctional Facility vanished into the wastes, leaving the prison empty. The Correctional Facility became another abandoned ruin in the wasteland, its carcass occasionally picked over by enterprising prospectors.
With the Dam firmly in their grasp, the NCR turned its attention towards wresting the Correctional Facility from Powder Ganger hands. The Powder Gangers are no match for the battle-hardened troops of the NCR, and summary execution awaited the Powder Gangers who managed to survive.
Do not kill Eddie and complete the endgame quest Eureka! for the NCR.
Most Powder Gangers at the Correctional Facility fled into the wasteland rather than face the advancing forces of the Legion. Those brave or foolish to remain were killed or crucified by the merciless Legionaries.
The NCR, battered by the loss of the Dam, were unable to devote any troops to retaking the Correctional Facility from the Powder Gangers. As a result, Powder Ganger raids on caravans became an unfortunate fact of life in the Mojave for years to come.
With Cooke dead, the Powder Gangers at Vault 19 fell apart. Those who weren't destroyed by the Courier fled into the hills or attempted to work their way back through the Mojave Wasteland. Few survived.
Armed with a wide array of improvised explosives and stolen weapons, the Vault 19 Powder Gang tormented the Mojave Wasteland for years. Citizens of the NCR were favorite targets, and they always suffered the worst fates.
After the Vault 19 Powder Gang surrendered to the NCR, they were re-incorporated into the correctional system. The NCR did increase their sentences, and they aren't about to take off time for good behavior.
Destroy ONLY the sulfur deposits below Vault 19 and convince Philip Lem to surrender to the NCR.
After the majority of the Vault 19 Powder Gangers joined the Great Khans, the weaker members scattered throughout the Mojave Wasteland. Though a few managed to erase their pasts, most never survived the journey.