Among their collection are guns from the battle at Gallipoli where our troops sneaked over enemy lines, killed Turkish snipers with knives and brought back their rifles.
These guns are on display in Te Papa's Gallipoli exhibit.
Of the 10 historical guns on show from World War I, six come from private collections, a Te Papa spokesman said.
"They help us materialise human experiences of Gallipoli and World War I and show visitors the warfare technologies of the time."
The collector said most military war history is in private hands, where the owners keep the guns in working order. With a ban on semi-automatic weapons, many of those working pieces of history could be sent to the melting pot.
For example, the collector has a semi-automatic weapon that was captured by the 28th Māori Battalion during World War II's battle of Monte Cassino, which is covered by the ban.
"This history matters to me, and it matters to Māori," he said. "But it doesn't matter to the anti-gun lobby; they don't care that our military history is being lost."
"We are shooting black powder weapons and keeping them in good working order," he said. "We are not in the business of glorifying war. We are in the business of preserving history."
The collector and his organisation accept there should be improvements to our gun laws, but he wants their voices to be heard.
"We have been to the police and told them [our concerns] about high capacity magazines," he said. "We are not happy about the [Christchurch terrorist attack], we are [more upset] because we have been saying let's do something, so these [attacks] don't happen."
While it is still unclear if these collectors will have to hand over their guns, they are preparing for the worst, while hoping for the best.
"The Government may say you have to cut a hole in the barrel and weld up the rifle, in that case, we would rather hand it in and have it destroyed," he said. "A welded rifle is a worthless chunk of steel."
The collector is sceptical about the Government's buyback scheme and whether it has enough cash, so the owners are not left out of pocket.
With the wholesale price for a semi-automatic rifle being about $2500, he believes the Government will have to double the $200 million it's preparing to put on the table.
"I don't want to see guys upset because they have [guns] confiscated," he said.
In the US state of Washington, legislation recently passed making it harder to buy semi-automatic guns. Sheriff Bob Songer is one of 21 sheriffs in the state who are not going to enforce the law, and he sees several problems with the gun buyback programme.
"If they don't hand back their guns are they faced with criminal charges?" the sheriff with 48 years in law enforcement asked.
"These guns are accepted, no questions asked. If you are a bad guy and your weapon has been used in a homicide, it seems like the perfect way to get rid of the evidence," Songer said.
Individual gun registration was abandoned in New Zealand in 1983 after police told the Government there was no evidence the registration of guns helped solve crimes.
"The issue with gun registration is partially the accuracy," the collector said. He owned guns before the changes, and half the time his guns' serial numbers were entered wrongly into the system.
"Gun registration always overlooks there has to be a human factor, someone has to look at the serial number," he said. "That human factor makes gun registration notoriously unreliable."
Sheriff Songer does not believe that gun restriction laws make our communities safer.
"You notice people don't talk about the bad guy behind the gun," he said. "I can get my gun out and lay it on the table, and it will never go off. The only time a gun goes off is when someone picks it up."
Police Minister Stuart Nash's office said details of the government's final Arms Act reform legislation is likely to be announced next week.
* Lyall Russell is a freelance radio producer formerly at Newstalk ZB.
