Cruz, speaking Friday, said he, Lee and Paul were yelled at by a number of their colleagues during lunches for co-writing a letter threatening to filibuster Senate gun control legislation.

"And I've got to tell you I don't think that there's an issue that has generated more heat internally in the Republican conference," Cruz said at a FreedomWorks event. "We've had probably five or six lunches with a bunch of Republican senators standing up and looking at Rand and Mike and me and yelling at us at the top of their lungs. I mean really upset and they said 'Look! Why did you do this? As a result of what you did when I go home my constituents are yelling at me that I've got to stand on principle.'

"I'm really not making that up. And I don't even to bother to argue with them. I just sort of let them yell and say look, vote your conscience."

Other Republican senators eventually signed onto the filibuster threat. In mid-April the Senate voted on the legislation. It failed to get the 60 votes it needed to pass the Senate.

Cruz said the Republican objection to their threat is that it made Republican lawmakers who did not sign on look like "squishes."

"But here was their argument. They said 'listen, before you did this the politics of this were great,' " Cruz said. " 'The Dems were the bad guys, the Republicans were the good guys, now we look like a bunch of squishes.' It's like, well there is an alternative, you could just not be a bunch of squishes."