Hayley Pointon, 30, was shot at a house in Hinckley, Leicestershire, as she visited her on-off boyfriend Nigel Barwell, in February 2013.
Aaron Power, 25 and Aaron Newman, 24, both of Coventry, had blamed each other for the killing.
The pair were ordered to serve a minimum of 31 years each for murdering Ms Pointon, of Coventry.
The eight-week trial at Leicester Crown Court heard that Mr Barwell was the intended target for the shooting.
Ms Pointon had been leaving the property when shots were fired, and died from a single gunshot wound.
The judge, Mr Justice King, said: "The scars you have inflicted on each family member will be long-lasting.
"This was in truth a calculated, cold-blooded murder. This was a planned killing and each of you were part of that plan.
"It may never be known who fired the shot but what is sure is each of you were involved in the killing and each had an intention to kill."
Hayley's mother, Kerry Pointon, said the family would try to rebuild their "shattered lives".
She said: "She can never be replaced in our lives and therefore we feel that there can never be any true justice for Hayley and her children."
A third man, Dylan Whitty, 30, from Coventry, was found guilty of assisting an offender. He is due to be sentenced on 8 September.
Three other men were cleared of the same charge.
Two men who shot dead a mother-of-two by mistake have been jailed for life for her murder.