The tax law in this country is a bit odd.
Organizations that are chartered as non profits can't lobby and still have donations be tax deductible.
So, CCRKBA is the lobbying arm of SAF.
NRA does the same thing, with the NRA-Institute for Legislative Action. On top of that, there is even more law that says neither group can donate money directly to a particular political candidate, so NRA has the NRA Political Victory Fund for that.
I'm sure I haven't explained the tax law part of it correctly, it's much more complicated than that, but that gives a general explanation.
