Okay so there I was... looking at my Häkke Test-A sniper rifle. I had to make double kills with this weapon to gather precious data for those damn scientists. To me personally I immediately thought this was to be done in the Crucible "Double Down!" is what came to mind. But I went on patrol and tried it out on some Cabal, ALAS! 10% was complete! Then I decided to try one more thing and pull out my Nightstalker bow and fire into a massive horde of Cabal and Hive who were advancing on each other. This linked a TON of enemies together, so I fired my test weapon into the middle of this mess (cue massive void explosion) aaaaaaand my prediction came true and my test weapon jumped to 100% instantly! Im not sure if this is common knowledge, but I figured I would share my find haha.