The second amendment was originally enacted to allow citizens to form militias. At the time of its enactment, the risk that the United States would fall under attack, primarily by Great Britain, was high. Nowadays, the chance that the United States will face a conventional invasion, of the sort a civilian militia would be effective, is very low. Because of this, the second amendment is more trouble than it is worth, as it does not serve its original purpose, and it allows for the shootings of many thousands of Americans a year. To prevent these shootings, the second amendment should be repealed.
Alternatively, add a clause to the second amendment, allowing right to bear arms to form militias when invaded or under imminent threat of invasion, to serve the amendment's original purpose only.