A ban in the United States on assault weapons expires on Monday because Congress has not voted to extend it.
Supporters say assault weapons are useful for self-defence
The right to carry weapons is a powerful political issue in the US with heated debate on both sides in the run-up to November's presidential election.
Brian Miller, whose brother was killed with an assault weapon, and Joe Bass, a member of the National Rifle Association, told BBC Radio 4's Today programme their views on the guns.
Brian Miller: My brother was an FBI agent working on a cold-case homicide squad at Washington DC Metropolitan Police Headquarters on 22 November 1994.
That morning a man - actually looking for a different office - walked into DC Police Headquarters, went upstairs, opened the door and opened fire with his assault pistol which was a Mac-10.
ASSAULT WEAPONS BAN
The 1994 bill bans the manufacture of 19 weapons, including those pictured above
Copies or duplicates of the weapons are banned
The law also prohibits features such as folding stocks, pistol grips and flash suppressors
Anti-gun activists say that, by making changes to these features, gun makers have continued to make arms nearly identical to pre-ban models
He was able to do this because the Mac-10 is small enough to hide underneath the jacket he was wearing but powerful enough to fire off dozens of bullets in a matter of seconds.
When the smoke cleared and the room could be entered, which was actually a couple of hours later because of the danger involved, my brother Mike's partner - another FBI agent, a female FBI agent, was dead, a DC police sergeant was dead, a third FBI agent was grievously wounded and the shooter had been killed in the gunfight as well.
I felt that [these weapons should be banned], I think, before this all happened but having experienced this in a more direct fashion, I certainly feel it more strongly now.
These are guns that are beyond what is acceptable in my view and frankly in the view of the vast majority of Americans in terms of what's acceptable in a civil society.
Joe Bass: ...But those same weapons can be used in self-defence. You know I'm sorry to hear about his brother and these other people, but those guns were already illegal in Washington DC where a regular citizen cannot own a gun, like I can here in Virginia, and so the criminals paid no attention to these laws.
I would like to have every possible gun I can possibly have in order to save my own life and the lives of my loved ones, including a semi-automatic assault pistol or rifle...
I certainly would want that kind of fire power if I needed it in a situation where someone was trying to kill me
We're not all about sports here. I mean we're talking about self-defence. The military puts grips on those guns [which make precision shooting difficult] because it makes them easier to use them - you can shoot them more accurately.
And in a self-defence situation that certainly is what you would want.
Brian Miller: It's not about accuracy Joe, as you know, it is about fire power. It is about the probability of getting multiple bullets out in a rapid stream as quickly as possible. That's why these guns are favoured by criminals and people who are intent on killing a lot of people at once.
Joe Bass: Well I certainly would want that kind of fire power if I needed it in a situation where someone was trying to kill me...
I have been in that kind of a situation - I helped save a man's life in the Rodney King riots in Los Angeles and I know exactly what that kind of a situation is.
I have had people come after me with a gun after I helped the police. And I have used a gun in a situation - I didn't have to fire it but I certainly had it in order to save a person's life.
Brian Miller: Why do you mention law enforcement, Joe Bass? Because it is in fact law enforcement, like my brother and the other people in that room that day who face these guns every day.
That's why over 2,000 police chiefs and sheriffs across this country from 37 states have said that they want the assault weapons banned - [for the ban to be] not only renewed but actually strengthened to close the loopholes that allow people to make copycat guns.
Our hope is, over time, to break that vice grip that the gun lobby has on Washington
[Asked why politicians were not listening to that argument] It is called money. It is called the ability of the gun lobby and gun makers who support the gun lobby to put money into political campaigns to scare politicians so that politicians are afraid of taking on the gun lobby.
And our hope is, over time, to break that vice grip that the gun lobby has on Washington.