It is about 2nd Amendment issues only!
The NRA doesn't get involved with social issues, defense issues, tax issues, monetary issues, foreign relations issues. national defense issues, property rights, religious issues, health or healthcare issues, politics, etceteras.
The NRA ratings and endorsements are based upon actual 2nd Amendment votes, not promises, campaign ads or dreams. If voting records are not available, questionnaires are used.
If everything appears fairly equal, they will support the incumbent, recognizing the value of seniority in the political games. If you can find another organization that does a better job of defending the 2nd Amendment, support them. Hint: There are not any. Not even close.
If the current administration and a newly elected Dem controlled House is successful in throwing out the Constitution, the Second amendment goes with it. Then the only way to get it all back is through revolt, and it is much easier to vote them out now, not be single issue. Why lend endorsement at all when both get same grades.
And many of us don’t want to put of a organization that shortsighted, to think that you can defend one of the Bill of Rights and ignore the rest.