Ratchet & Clank PS4 OOB, Bolt Grinding and Weapon Leveling on Rilgar

Respawning ameoboids keep the bolts and experience coming (until you touch down on the plaza.) If you do this earlier in the game, they respawn in greater numbers. This 8+ minutes got me over 250,000 bolts. (Game speed setting set to Fast.)

(You can also do this with the out of bounds glitch overlooking the Containment Center.)