Today at 7pm, Charles Leski Auctions in Melbourne will be selling the pistol used by Ned's younger brother, Dan Kelly, who died during the Glenrowan siege. Estimates are $100,000 to $125,000. While the jury is still out on Ned's status as hero or villain, there are enough serious collectors of Kelly memorabilia - and bushranger material in general - to make this a significant occasion.

Most of Ned's known possessions are held by public institutions, so the opportunity to own his brother's gun is about as good as it gets. The existence of the pistol is well known among collectors and historians, although many doubted it would become available in their lifetime.

It has been held by the same family since 1900.

The pistol has an interesting history, and although the provenance is not exactly bulletproof, there's enough circumstantial evidence to satisfy most collectors. It is described in the Leski catalogue as an East India Company Cavalry Pistol, originally made by Samuel Marson then converted to a percussion cap system around 1840. The most important feature is the inscription ''1876/Dan Kelly'' carved into the walnut handle with a knife.

This was certainly the type of weapon preferred by bushrangers on horseback, and there are contemporary reports of a muzzle-loaded single-shot pistol being found on a Kelly packhorse at Glenrowan. It can't be confirmed that this is the one being sold.

This pistol was discovered in Rockhampton in 1900, when a local gunsmith, P.H. Hansen, bought a box of old weapons that included this item.

It was covered in dirt, rust and grease and it was only after Hansen cleaned it that he saw the Dan Kelly inscription on the handle.

The seller told Hansen he found it on the banks of the Murrumbidgee River some time ago. This story was published in October 1900 in The Morning Bulletin, a local Rockhampton paper.

One of Hansen's descendants is selling the pistol tonight.

A director of Australian Arms Auctions, Roland Martyn, has provided a written opinion as to the pistol's authenticity. He also supplied the Leski valuation.

Kelly collectors will remember that another gun with alleged Kelly connections was sold through Mossgreen in 2007.

The .32-calibre pocket revolver had been discovered during the demolition of a Forbes house that was formerly occupied by Kate Kelly, Ned's sister. The initials ''KK'' were inscribed on the handle and it was claimed that Ned or members of his gang had given it to her.

This revolver had previously been listed at a 2006 auction at the State Library of NSW (with a wildly optimistic estimate of $400,000) but was withdrawn before the sale.

It fetched $72,870 at the Mossgreen sale but, soon after, some antique firearms experts approached The Age claiming this model was not manufactured until 1884, making any direct Ned Kelly connection irrelevant. Without this, its value was estimated at $400.

Controversies such as these are not uncommon in the world of Kellyana. There's a small industry devoted to this niche market relating to Ned, his family, other gang members, and even the police officers involved in the Glenrowan siege.

Even postcards have value. Another item listed by Leski tonight is a 1907 Regal Co. postcard featuring an 1870s photo of Ned and Dan Kelly and Steve Hart on horseback. These are so rare, its estimated value is $600 to $800, close to the Australian record for a postcard if it sells above the higher figure.

Rarer still are examples of the five legal briefs - ''The Queen v Edward Kelly'' - relating to the murder of police constable Thomas Lonigan. One 55-page document sold for $25,000 in June 2000.