To unlock this trophy, you'll need access to the Arm upgrades in Storm Owl's stage (and potentially Lightning Web from Web Spider to reach the capsules).
Once you make it to Area 2 of Storm Owl's stage, progress through before the first set of boss doors, you'll notice a small wall with spikes above it. If you shoot off Lightning Web in front of the spikes you can wall jump from the web to the edge of the floor above them.
There will be 2 sets of Buster capsules: What you choose to stay with is your choice. But whatever you choose, head into the capsule of the other Arm upgrade and lob off a charged shot before choosing your preferred capsule.
Why? Because in order for this to be achieved, you need not only your Buster of choice and the 8 Weapons to be xhaeged, but the other buster upgrade charge shot as well to pop the unlock!