Washington: Julie Golob, a professional sport shooter and a strong public advocate for gun rights, is resigning from the US National Rifle Association board before the end of her three-year term.

She is the fourth member in the past two weeks to leave the board of the NRA in a sign of further upheaval within America's most powerful gun rights group.

In the latest national furore over mass killings, the tremendous political power of the NRA is likely to stymie any major changes to gun laws. Credit:AP

Golob, a regular on shooting shows who has won competitions and is an advocate for women's use of firearms, did not state a reason for her departure in a note posted on her website.

"I am proud to have had the opportunity to represent the members of the NRA but I can no longer commit to fulfilling the duties of a director," she wrote pledging to continue to support NRA "programs and sports" and advocate for "the preservation of freedom".