The Tories want to end unfair trials of veterans where no new evidence has been produced and the accusations have been questioned exhaustively in court.
If they win a majority at the election, the party will amend the Human Rights Act so it does not apply to incidents - including deaths during the Troubles - which took place before the law came into force in 2000.
The pledge is among a package of measures the party is proposing to support military personnel, veterans and their families.
Their proposals came as:
- Labour's Keith Vaz, who was facing suspension from the Commons for six months after he was found to have "expressed willingness" to purchase cocaine for others, announced he would not stand at the election.
- The Tories faced mounting pressure to publish a report by the Intelligence and Security Committee examining Russian influence in British politics - following reports that it names oligarchs and wealthy Tory donors.
- Nigel Farage, who is facing calls to stand his Brexit Party candidates down in seats where they could split the Tory vote, will continue his nationwide campaign tour in the North East.
- The Liberal Democrats pledged to give every adult in England £10,000 to spend on education and training throughout their life as part of a "skills wallet" scheme.
- The Guardian reported that Labour would meet on Monday to thrash out the details of its migration policy - after shadow cabinet minister Andrew Gwynne refused to say whether the party would end freedom of movement.
Mr Johnson, who will visit the Black Country to mark Armistice Day, said a Tory government would "always support" the Armed Forces.
He said: "As we remember the ultimate sacrifice made by our brave men and women for their country just over a century ago, it is right that we renew our commitment to the soldiers, sailors, marines, airmen and veterans of today."
The Conservative pledge includes measures to guarantee veterans job interviews for public sector roles, provide Ministry of Defence funded "wraparound" childcare, and tax relief for companies which hire veterans in the first year after they have left service.
It follows a furious row between the Tories and Labour over the cost of Jeremy Corbyn's policies, which saw John McDonnell accuse the Conservatives of spreading "fake news".
Analysis by Mr Johnson's party claims that Labour would spend £1.2 trillion over five years - based on costings for the party's last manifesto and its most recent pledges.
It assumes the Opposition would immediately sign up to the 32-hour week, abolish private schools, and pilot a universal basic income.
Mr McDonnell condemned it as an "incompetent mish-mash of debunked estimates and bad maths", but the Chancellor Sajid Javid defended the dossier - claiming Labour would plunge Britain into an economic crisis "within months".