(CNN) - A large alliance of gun owners announced Sunday it supports the bipartisan compromise on gun sale background checks that senators announced last week.
The chairman of the Citizens Committee for the Right to Keep and Bear Arms, Alan Gottlieb, sent a message to members and contributors stating the bill "bans any federal gun registry and carries a 15-year prison term for anyone who violates it."
"We protect and expand a good number of pro-gun rights measures as well," Gottlieb continued, noting he and one of the group's lobbyists had helped craft the deal. He cited measures like making interstate gun sales easier, and restoring gun rights to veterans, as reasons for his group's support.
The background check compromise measure was brokered by Democratic Sen. Joe Manchin of West Virginia and Republican Sen. Pat Toomey of Pennsylvania. It extends checks to gun shows and Internet sales but not to private sales.
The country's largest gun-rights group, the National Rifle Association, reiterated its opposition to the measure Sunday.
"NRA is opposed to Manchin-Toomey, and it will be a scored vote," NRA spokesman Andrew Arulanandam said, meaning senators' ratings with the organization will be affected by how they vote.
The Bellevue, Washington-based Citizens Committee for the Right to Keep and Bear Arms bills itself as the second-largest gun rights lobbying group and says it has about 650,000 members and contributors, compared with the NRA's 5 million.
The NRA and other groups opposed to the Manchin-Toomey measure are "unwilling to take the hits," Gottlieb told CNN.
Toomey wrote on Twitter Sunday, "Glad to have the support of Citizens Committee for the Right to Keep and Bear Arms."
And Manchin called the group's endorsement "huge" in an appearance on Fox News.
"It is a win for us," he insisted.
While he has heard from members of his group who are upset at its endorsement, Gottleib said it "is expected."
"A lot of the people don't trust anyone," he continued.