Congressman Ken Buck, who has campaigned for nearly two decades on his pro-gun stance, finally found a gun safety bill he could support, at least until it came time to vote for it.

Buck, a Republican, is a co-sponsor of a proposal to create a voluntary waiting period to purchase a firearm, but ultimately voted against it after its hearing Wednesday in the House Judiciary Committee. Back in July, Buck co-sponsored H.R.8361, the bill introduced by Pramila Jayapal (D-WA) with the goal of preventing those who may experience suicidal thoughts from being able to immediately obtain a gun.

Anyone may add themselves to the “no-buy” list, which firearm dealers would consult as part of the national instant criminal background check system before making a sale. Those who change their mind can remove themselves from the list after a three-week waiting period.

Buck’s co-sponsorship of this bill angered Colorado’s most extreme gun rights group, the National Association of Gun Rights (NAGR), the national arm of Dudley Brown’s Rocky Mountain Gun Owners. NAGR’s sent an email on Tuesday urging its members to call Buck and demand he “reverse course” and pull his support.

Yesterday, during the House Judiciary Committee hearing on the bill, Buck did just that.

“I have proudly cosponsored this legislation because I believe in doing everything we can to minimize suicides and protect people from themselves under certain circumstances,” said Buck. “I have issues with this bill and I will ask the gentlelady [Jayapal] if there’s a way to work to address them before or after the end of this markup.”

Buck then listed several changes he wanted to make to the bill.

Buck’s explanation for his flip-flop after being a co-sponsor for five months? He didn’t read the bill carefully enough.

“I apologize to my friend from Washington [state] for misleading her when I initially co-sponsored this bill,” he said. “I still would like to work on this bill, make it stronger and bring it back — since we have six days left in this Congress, perhaps next Congress — and see if we can’t do something to reduce the number of suicides in this country.”

Jayapal welcomed some of the changes Buck suggested and thanked him for his partnership and for reading it thoroughly, to which Buck replied, “I wish I’d read it thoroughly earlier.”

In another email sent after Buck voted against the bill, NAGR asked its members to call Buck again and vote against the bill, this time on the floor.

“The tremendous backlash from the pro-gun grassroots has already caused one Republican Congressman to abandon his support of this gun control scheme,” the email also noted, without mentioning that the Congressman in question was Buck himself.

Buck’s office declined to comment beyond his statements during the hearing.