Police marksmen cannot "see the wood for the trees" because of reams of complex guidelines, a coroner said.
Paul Knapman, who oversaw the inquest into the death of barrister Mark Saunders, said the paperwork burden must be slashed.
In a letter to Home Secretary Theresa May, he said senior officers must encourage "common sense" and not a "slavish adherence" to documents and protocols.
Dr Knapman also said police should consider bringing a top level officer from any force to attend the most difficult operations. He said the officer should be given "huge authority" to review tactics, take a fresh look and change them if necessary.
A jury at Westminster Coroner's Court ruled Mr Saunders, 32, was lawfully killed by Scotland Yard snipers when he brandished a shotgun at them.
But it highlighted shortcomings in the police operation including confusion among senior ranks and a lack of consideration for the barrister's vulnerable state.
Dr Knapman said: "My perception is that 'not being able to see the wood for the trees' may be a problem. You may take the view (or encourage others with power to alter things to take a view) that much of this material may be amalgamated, simplified or dispensed with.
"You may also take the view that there has been over reliance upon the printed word of instruction in the police service (as with other public services) in recent times.
"It may be that there is merit in encouraging one or two shorter documents and all documents set out in simple and unsophisticated language thereby minimising jargon - indeed, encouraging more common sense rather than slavish adherence to written documents and protocols."
Dr Knapman highlighted six firearms manuals and guidance documents printed by the Met, Association of Chief Police Officers (Acpo), Home Office and National Policing Improvement Agency (NPIA).