So the 2 Vector Submachine Gun variants in The Division 2, the SBR 9mm and the .45 ACP, are among the most sought after weapons in the game at the moment.
Not only do they look really cool, they have the highest rate of fire among all the weapon types in the game and can absolutely shred through your enemies, especially with the proper accompanying gear and attachments equipped.
And while there doesn’t seem to be a guaranteed way to get these guns to drop, there are some methods that are more likely than others to yield results.
First of all, just do bounties and generally attempt Invaded Strongholds. Elite enemies have a higher chance in these missions to drop higher Gearscore weapons, and I personally found two Vector SBR 9mms within minutes of each other while doing the Capitol Building Invaded Stronghold.
Secondly, look at the Control Points scattered around the map. Once you reach World Tier 4, you will have the option to upgrade enemy Control Points by completing events linked to them with red lines.
Complete these events and bring the Control Points up to level 3, and then capture them for guaranteed Blueprint drops. This obviously requires a bit of grinding to get a Vector Blueprint, but it allows you to always have the ability to craft one.
The Gear Score of crafted weapons however is randomly generated, and might not always be close to what you need.