Hard Brexit Tories will use a Commons vote to try to overturn Home Office plans to ban high-powered military-grade rifles in a show of political defiance aimed at Theresa May.

Police want the .50 calibre or higher weapons – which can immobilise a vehicle or truck from a mile away – banned because they fear a terrorist who got hold of one would be impossible to defend against.

But 35 Tory MPs – many of whom are understood to be members of the European Research Group (ERG) – have decided to back an amendment to block the proposed ban.

Steve Baker, Sir Bill Cash and Sir Bernard Jenkin are among the 35 Tory MPs supporting the amendment to the offensive weapons bill that would prevent a ban on rifles that have a power of “over 13,600 joules at the muzzle”.

David Jamieson, the West Midlands police and crime commissioner and former Labour MP, said he was “extremely concerned” to learn of the proposed amendments.

“Such weapons have no place in this country to be the possession of non-military personnel,” Jamieson wrote to Sir Geoffrey Clifton-Brown, the Tory MP behind the amendment

Royal Marine snipers from 42 Commando M Company Corporal Richie Mockler and Lance Corporal Nick Young test firing a Barrett .50 calibre sniper rifle at a range in Iraq. Photograph: Jon Mills/REX/Shutterstock

“You will be aware it was .50 calibre rifles which were used by the IRA to murder British soldiers and members of the Royal Ulster Constabulary in the 1990s. I can see no reasonable explanation for any member of the public to own such a weapon.”

MPs were informed that 129 rifles of .50 calibre were held under licence in England and Wales, mainly to be fired on Ministry of Defence ranges in long-range shooting competitions.

Critics of the proposed ban have said that no .50 weapon has been used in a crime in the UK since the IRA disarmed. Clifton-Brown told MPs in June he believed the ban was disproportionate, and that people who hold firearms are “some of the most law-abiding people in this country”.

Members of the hard-Brexit ERG have been looking for a chance to show Theresa May they are unhappy with her Brexit strategy, and the bill is the first available opportunity.

Their aim is to warn the prime minister they have the numbers to vote down any Brexit deal based on Chequers. If more than 15 Tory MPs are prepared to vote alongside Labour, the SNP and other opposition parties, May’s deal would almost certainly be voted down.

Police forces support the ban on the guns, which the National Crime Agency says have the power to immobilise a light or medium-size vehicle or truck at 1,800 metres and are too powerful to be used for sporting purposes.

Mark Groothuis, the national firearms licensing liaison officer for counter-terrorism policing, also told MPs during the bill’s committee stages that he was concerned that “if one of these guns were to be stolen, again with the ammunition, and if it were to get into terrorist hands, it could be very difficult to fight against or to protect against.

“There is very little – nothing, as far as I know – that the police service have that could go up against a .50 in the way of body armour or even protected vehicles,” the senior police officer added.

Louise Haigh MP, the shadow policing and crime minister, said: “These rifles are weapons of enormous and destructive power, which senior officers have warned they have no known protection against. They should have no place in the hands of the public. Tory MPs should come to their senses, and stop playing politics with public safety.”

The Clifton-Brown/ERG amendment also has the support of the Democratic Unionist MP Sammy Wilson, whose party has threatened to vote down the budget, and one Brexit-supporting Labour member, Kate Hoey.