ST. LOUIS — Republican presidential candidate Mitt Romney will tell National Rifle Association members that President Barack Obama is not protecting gun owners’ rights, even though the administration has said little about firearms and has deeply disappointed gun-control advocates.

In remarks prepared for the association’s annual convention Friday, Romney says “we need a president who will enforce current laws, not create new ones that only serve to burden lawful gun owners. President Obama has not; I will.”

The excerpted remarks, released by Romney’s campaign, offer no details about Obama’s record on firearms.

Romney’s speech comes as the former Massachusetts governor is trying to woo conservative groups in a bid to consolidate his base before the fall campaign. His relationship with gun owner groups is an uneasy one. Running for the Senate in 1994, Romney said: “I don’t line up with the NRA.” He later became a lifetime NRA member.

Obama has placed little emphasis on gun issues, to the dismay of groups such as the Brady Center to Prevent Gun Violence. In its most recent assessment, in 2010, the group flunked on Obama on all seven issues it deemed important and expressed disbelief at his performance.

Campaigning in 2008, Obama said: “I believe in the Second Amendment. I believe in people’s lawful right to bear arms. I will not take your shotgun away. I will not take your rifle away. I won’t take your handgun away. ... There are some common-sense gun safety laws that I believe in. But I am not going to take your guns away.”

In his prepared remarks, Romney hints that Obama wants to erode gun rights, without saying so explicitly and without offering details.

“This administration’s attack on freedom extends even to rights explicitly guaranteed by our Constitution,” Romney says. “The right to bear arms is so plainly stated, so unambiguous, that liberals have a hard time challenging it directly. Instead, they’ve been employing every imaginable ploy to restrict it.”

The NRA gathering in St. Louis comes at a moment of heightened national concern about gun use because of the explosive Florida case in which a volunteer neighborhood watchman fatally shot an unarmed teenager. The NRA strongly backed Florida’s “stand your ground” law, which is at the heart of the unfolding legal matter.

It won’t be the first time Romney has had to walk a careful line between appealing to conservatives, who form his party’s base, and trying not to alarm independents, who will be crucial in the fall campaign.

The NRA is so vital to Republican politicians that Rick Santorum, who suspended his presidential candidacy on Tuesday, is keeping his appointment to speak just after Romney. Others scheduled to speak at the “leadership forum” are GOP presidential candidate Newt Gingrich, Texas Gov. Rick Perry and House Majority Leader Eric Cantor, R-Va.

When Romney ran successfully for Massachusetts governor in 2002, the NRA gave his Democratic opponent a higher rating on gun-rights issues but made no endorsement.

Massachusetts quadrupled its gun-licensing fee while Romney was governor. He signed a law that made permanent a ban on assault-type weapons, although it was coupled with measures backed by gun-rights groups, such as the creation of an appeals board for people seeking to restore their gun licenses.

As he was considering his first presidential run in 2006, Romney signed up for a lifetime NRA membership. He calls himself a strong supporter of gun ownership rights.

Romney drew snickers in 2008 by claiming he sometimes hunts “small varmints.” He showed more humility and humor last month in Alabama, where he said he hoped to go hunting with a friend who “can actually show me which end of the rifle to point.”

Although the Trayvon Martin case in Florida might stir new debate, gun issues have sharply faded in recent presidential elections. Obama rarely broaches the topic. GOP candidate forums often elicit no questions on the subject.

The NRA speech is Romney’s only scheduled public appearance until Monday. The focus on gun rights will mark a sharp turn from the heavy emphasis on female voters and women’s issues in the past several days.

The NRA’s website urges families attending the convention to “spend the day exploring the products from every major firearm company in the country, book the hunt of a lifetime in our exclusive outfitter section and view priceless collections of firearms in our gun collector area.”

Romney planned to spend Sunday raising money in Naples and West Palm Beach, Fla.