In one case in the past 18 months, people infiltrated a gun club in northern NSW to work out who had firearms at their home before stealing them. 

More recently, police uncovered 28 guns at a man's house in Sydney's west that had been allegedly stolen from several properties in central west NSW, near Forbes. It is alleged the weapons were destined to be sold on to an outlaw motorcycle gang.

"In the two years I have been commander, we have seen a rise in rural gun theft where they are picking properties that are isolated or aren't necessarily the home residence, where guns are stored," firearms squad commander Detective Superintendent Mick Plotecki​ said. 

New data obtained by Fairfax Media shows almost 92 per cent of the 258 firearms stolen this year (up to March 31) have come from rural and regional areas, including Newcastle and Wollongong. 

Last year 537 firearms were taken from rural and regional areas – accounting for 92.6 per cent of all guns stolen in NSW.

That figure is up from 81 per cent in 2014. 

While the proportion of guns nicked from rural locations has increased, the firearm theft in NSW dropped considerably from 731 in 2014 to 580 in 2015.

Superintendent Plotecki says some landholders will have guns stolen but not report missing the grey market firearms – weapons acquired before the 1996 buyback.

"In 1996 with the buyback, a lot of people just didn't bother to hand the guns in," Superintendent Plotecki said.

"There is a lot of situations where your grandad dies, you go around to his house and find a .22 in the garage.

"Trouble is though with those guns, a lot of them end up in the hands of criminals because people sell them, give them away or criminals break into a house and they will steal one legitimate gun and 10 grey market guns."

As recently as this week, a landholder near Wilcannia, in western NSW, noticed five registered bolt-action rifles had been stolen from a safe in a shed.

Such a firearm can fetch about $200 to $300 while the higher end "Ferrari guns", like Glocks, can attract up to $30,000 depending on the buyer.

Police are seeing a mix of opportunist thieves, who steal from country sheds and shop around their ill-gotten gains, as well as bikies recruiting "associates" in steal-to-order arrangements. 

The trend, and police acknowledgment of it, is a shift from a few years ago when the former firearms squad boss said there was no evidence guns stolen from rural areas were used to supply bikie gangs in Sydney.

In the central NSW case in April, detectives found alleged links between 31-year-old Jesse Leonard Menzies, who was charged over the firearm haul after being arrested near Penrith, and bikies in the city. 

In general, some stolen weapons end up in the hands of city criminals, others circulate regional markets and a lot also get cached.

"What we have seen is a lot of them pool their guns and they will basically take it out, and if it is used and it's likely going to cause them grief, they will dispose of it," Superintendent Plotecki said. 

"If they don't use it they will bring it back to the pool."

Some landholders adhere to regulation by keeping guns in approved containers but police are pushing for owners to keep the firearms at their primary residence.

"Ideally in a place that is well hidden, not obvious. Preferably they store the weapons separate to the active part of the gun and store the ammunition separately," Superintendent Plotecki said.

Greens MP David Shoebridge, who recently obtained figures identifying the hot spots in NSW for private arsenals, said sometimes guns were stored in a shed where tools were at hand to break into a gun safe.

"The best solution is to reduce private arsenals in the first place. But under the current regime, a sensible reform would be having the guns stored at a place where they would have constant supervision not a remote shed with nobody there," he said.