In previous iReports, I have suggested that improving gun control laws will be very difficult without making changes to the Second Amendment. Here, I will argue in favor of imposing legal limits on the firepower that individual US citizens can own. I've read thousands of gun-related discussion entries in Disqus and iReports on CNN. The suggestions here are based on my assessment of the rationales given by hundreds of pro-gun and pro-control posters.

As background, note that I support registration, licensing, and psychological testing for all gun owners. I will not discuss this further in the present iReport.

I suggest dividing weapons into categories by 1) effective range, 2) maximum number of rounds per minute (including clip swaps), 3) magazine capacity, and 4) concealability. If the categories were arranged suitably, and a maximum of 3 bins were assigned to each specification, the total number of bins would be 81, and any gun could be placed into these bins according to its specs. For this iReport, I will make a case for imposing an upper limit on (2) firing rate and (3) magazine capacity. Guns operating above these limits, I will call assault-type weapons (ATW). I do not care whether the gun is used by the military or not. Nor do I make any distinction between automatic and semi-automatic guns.

Qualitative limits and rationales

Pro-ATW. Here are the major rationales presented by citizens who believe they should be permitted to own assault-type weapons.
(Pro1) The ownership of any gun I desire is an inviolable right, guaranteed by the Second Amendment.
(Pro2) I need it for self-defense.
(Pro3) It could stop a crime in progress.
(Pro4) I need it to protect the USA from establishing a tyrannical government.
(Pro5) An ATW ban would only keep these guns out of the hands of "good" persons, while "bad" persons will have the same access as without any restrictions.
In making this list, I completely discount arguments that bombs, cars, sticks, pens, and spoons are also assault-type weapons and must be treated in the same way as guns.

Anti-ATW. Here is a similar list put forth by gun-control advocates.
(Con1) Depends on how the Second Amendment is interpreted. Many SCOTUS cases over many years have established that there are limits on this "right".
(Con2) Don't need an ATW for self defense.
(Con3) Don't need or want an ATW at a crime scene.
(Con4a) USA has 200 years of experience in protecting citizens' rights, and a tyrannical regime is very unlikely.
(Con4b) ATW's would not help if such an eventuality occurred. Citizen control of the government is maintained through other means than guns.
(Con5a) Making possession of ATW's by a citizen illegal makes policing of the law easier.
(Con5b) Making possession of ATW's illegal would make access to these guns more difficult.
(Con6) Anarchy and insurrection are as much the enemy of freedom as is tyranny.

My assessment and recommendation

The Pro-ATW rationale is very much weaker than the Anti-ATW rationale. In terms of the number of people who would be affected by an ATW ban, very few would be affected. Nonetheless, the benefits of such a ban would exceed the drawbacks. The limits suggested here are estimated to be helpful in reducing the death toll in mass shootings. A citizen should be prohibited from owning or carrying a weapon if it has a maximum firing rate greater than 6 rounds per minute or a magazine capacity greater than 6. I think these limits or similar ones should be applied cumulatively to weapons that are being "collected" or "carried". With these limits, two semi-automatic pistols could easily exceed the legal carry threshold for an ATW. This would limit owners who collect 60 guns, or who carry 4, keeping an individual's firepower within reasonable limits.