Sheer Force raises the base power of all damaging moves that have any additional effects by approximately 30% (a multiplier of 5325/4096), but their additional effects are ignored. Sheer Force also boosts Jet Punch, despite the fact that this move has no additional effects.
If (and only if) a move is boosted by the effect of Sheer Force, several effects that normally happen after attacking will be skipped. This includes the effects of Eject Button, Red Card, Shell Bell, Kee Berry, and Maranga Berry; the recoil damage from Life Orb; the Abilities Color Change, Pickpocket, Wimp Out, Emergency Exit, Berserk and Anger Shell; as well as Meloetta's opportunity to switch forms if it acquires Sheer Force and uses Relic Song. Other effects are not negated this way; therefore, if a Pokémon with Sheer Force holding a Life Orb uses a move boosted by Sheer Force, it will gain the passive damage boost (because it isn't a secondary effect of the move nor is it on the list of skipped effects), but the Pokémon will not be damaged by the Life Orb.
Documentation
https://bulbapedia.bulbagarden.net/wiki/Sheer_Force_(Ability)
Relevant Code Points
More research needed.