The president has the power to ban the important of guns and ammunition. If you think that ammunition is already very costly and difficult to find, this new rule will make it worse. This is part of Biden’s policy to reduce gun ownership by making it more costly.
From Biden’s State Department:
“New and pending permit applications for the permanent importation of firearms and ammunition manufactured or located in Russia will be subject to a policy of denial.”
While the new policy mentions prohibiting the importation of both firearms and ammunition, importing Russian-origin firearms was already extremely restricted under past executive policies. The new rule will primarily affect the importation of ammunition.