"Daily at noon, all US citizens will spend 15 minutes calling upon one or more divine beings to prevent unfit people from purchasing weapons, or alternatively, to "save us" from murder by semi-automatic and automatic weapons exceeding .22 caliber, and containing magazines with a capacity greater than 7 cartridges. Prayers must be conducted in an earnest, forthright and unequivocal manner."
You'll probably encounter some objection from the church-state separationist crowd; this will be easily defeated by accusing them of "hating Jesus."
Clearly it's not possible to control guns through any earthly or human effort. We must then marshal the spiritual resources of our population to call then upon the heavenly forces to resolve this wicked problem. Thank you.