MidwayUSA.com and a few of the other online firearms companies also participate in the NRA Roundup Program (NRA-ILA National Endowment). Information here...
https://www.midwayusa.com/nra-support
For customers, contributing is easy. Watch for the check boxes during checkout to round up those cents to the dollar for the purchase, or to contribute more if desired.
There was an application in the box with my new Ruger.