But imagine if the NCR drafted...

Plus, it is going to come down to how much ammo the BoS has. Regardless of any division. I mean NCR had 700,000 citizens in like 2240 or something. That number has no doubt increased over the 40 years. I'm not sure if the NCR has a draft going for the Mojave Campaign but seriously... That is an incredible army. Worst case scenario for the BoS, it would probably be a battle like "New Alamo" or something. Or in SST 1, at the Whiskey Outpost... arachnids being the NCR...

There are some issues. As much as I want to see MWBoS as a powerful faction that control from cheyenne mountain to Chicago. Bethesda has said they have fallen on hard times. We don't know what shape they are in since Tactics. Lyons controls a small chapter in DC that had split. Outcase are stil an issue and once Lyons kicks off and the original bos that came with him die in battle the only members left would be the "new bloods." The "new bloods" might no prove good brotherhood material and cut and run.

Western BoS would put up a hard fight against NCR and NCR would win but it would be bloody for the NCR.

Equipment and training only goes so far. If you throw more men on the field then the enemy has bullets, then you will win. And, with the East Coast BoS fighting the Supermutants and Enclave Remnants for so long, I doubt they could go toe to toe with the NCR.

NCR at the end of Fallout: New Vegas would probably be able to beat the combined might of all of the BoS chapters as they are simply much larger than the Brotherhood. But give it ten or twenty years and the East and Midwest BoS will have grown in size and power significantly due to their active recruiting and large support base. The NCR doesn't have as much freedom to grow anymore as it's coming up against other large powers.

The Midwest and East Coast BoSs will keep growing while the NCR won't be able to do so without large-scale warfare.

so service rifles can destroy optimus prime liberty prime?