If gun owners truly voted as a real complete bloc, we might be amazed at what we could accomplish. Even if only half of us voted in lockstep.
As it is, there's very few of us that can be really counted on, and even then we put the fear of the electorate into most of the legislators (not all of them, there's too many districts where we're too thin on the ground to amount to much).
Methinks Jeff Knox nailed it. When crunch time comes many NRA members get wrapped up with stuff unrelated to our Second Amendment rights.
Not saying all 4M+ member's WILL contribute, but they have the POTENTIAL to contribute, and therefore, the NRA has a huge amount of untapped potential reserves.
Potential and reality are two different animals. About ten percent of NRA members donate to the ILA and PVF. This is the reason for frequent requests for donations that many NRA members whine about. Each request for donations brings in about one million dollars, pocket change to Bloomberg.