Like the Recluse, the Mountain top grenade launcher is one of Destiny 2's advanced weapons. When it was first introduced, the quest was a ridiculous grind that involved obtaining multiple skills and medals in triple-digit amounts in the Crucible. Thankfully, Bungie tweaked the requirements, making Mountaintop a doable weapon for anyone willing to put in a little work.
How to start the quest on top of a mountain?
Just like other Crucible tech weapons in Destiny 2, you'll need to take a quest from Shaxx. The quest, which is called "The Ascent", requires you to reach the glory rank of the brave, which only needs 200 glory points. This is the easy part of the quest. The next step is where the grind begins.
The next part of The Ascent asks you to complete a Triumph called "In Pursuit of Honor". To complete this Triumph, you'll need to enter the Crucible and earn 750 Grenade Launcher shots. On top of that, you will also need 75 double kills and 25 calculated trajectory medals (triple kills). It's worth noting that playing in Iron Banner or Competitive will earn you bonus progress, with kills in the former being worth double and kills in the latter being worth triple.
What should I do after completing the Triumph?
After completing Triumph Chasing Honor, you will need to return to the Crucible, but this time you need to achieve Legendary Glory Rank. It should be noted that reaching Fabled in the Crucible is also part of “The Stuff of Myth” triumph, which is a key milestone in acquiring the Recluse machine gun. Fabled requires you to rack up 2100 Glory, but luckily earning Glory is much easier due to some Crucible changes brought about by Destiny 2's Shadowkeep expansion. Also, solo players don't have to worry because there is a Freelance Survival playlist that has a maximum size of one game. Hitting Fabled is the easiest ever, but it can still be a daunting task.
What happens after reaching legend?
Once you've gotten all your grenade launcher shots and reached Fabled by getting 2100 glory, it's time to head back to Shaxx at the tower and turn in The Ascent quest. He'll give you your own mountaintop, which fires micro-missiles instead of grenades. Since you have already reached Fabled by doing this quest, you are almost done with the Recluse quest. To wrap up this quest, you need to run a few more Crucible matches, but what better way to test out your new mountaintop?