The Defence Forces had to dismantle thousands of weapons last year including rifles that would have been of considerable value to collectors.
Strict rules prohibit the Irish military from selling weaponry to anybody except the manufacturer or another government, where feasible.
However, defence sources said the weapons that were decommissioned could have netted a significant payback for the state had it been possible to sell them.
An inventory of items details how 1,714 pistols, many of them Browning weapons, along with 1,555 rifles, mostly Lee-Enfield .303 rifles, were destroyed.
A defence source said the rifles especially were still valuable and had they been sold could have generated a significant payback for the exchequer.
That was not all the weaponry that was decommissioned either, with 208 light machine guns and 96 heavy machine guns also scrapped.
In addition, twenty three 20mm cannons were destroyed, along with three mortars, seven anti-tank guns, and 564 assorted barrels for the weapons that were disposed of.
A further 155,438 associated spare parts were also scrapped, according to information provided by the Defence Forces.
Internal records detail how the Defence Forces’ hands were tied over how they could dispose of the weapons.
A letter from Jacqui McCrum, the Secretary General of the Department of Defence, said permission had been granted for sale of some of the weapons in 2012.
However, this was superseded by new rules that were introduced three years later.
Her letter said: “New policy stipulations for stock disposal in the nature of weapons and ammunition introduced in April 2015, strictly limit customers of such sales to the original manufacturer or their authorised agents only, or another government, where feasible.”
She said that based on that policy change and the absence of a buyer for the weapon, she would “welcome plans for the destruction event” last July.
Ms McCrum wrote: “I would, however, emphasise the need for thorough, detailed and documented records of the items destroyed to facilitate the ongoing process of reconciling … items procured with public funds.”
The letter also explained how the Defence Forces had invited a representative of the department to be present at the destruction to “provide additional assurance”.
Internal emails also describe how some of the weapons were held back for museum or display purposes after first being deactivated.
Another message said rifles would require stripping of their wooden components as a shredder would only destroy metallic parts.
An email said: “It is expected that this disposal process will take less than ten days and further processes are being planned for.”
Security analyst Declan Power said: “It’s another example of how the Defence Forces have their hands tied behind their back in ways that do not always benefit them.
“Some of these items have a resale value and it would seem to make more sense that they could be sold on to at least get some return from the taxpayer, or at least for that option to be explored.
“Whatever money was raised through their sale could have been reinvested into new equipment, or into the general defence budget.” Asked about the records, the Defence Forces said they had nothing further to add to their contents.