As to the original question - how to dispose of it:
It has some value if anyone wants the hassle of describing it, and offering it on eBay or whatever. If it were mine and I wouldn't want the hassle of that. Every local Council throughout England has waste disposal/recycling sites, with large containers into which to put wood, glass, plastic, garden waste, metal, used engine oil, scrap TVs/computers etc. As I said earlier, I'd just dump it in scrap metal - job done.
And there are no 'bullets' in it that could cause harm if misused by kids or delinquents - they're just powder cartridges. Think of them as 'blanks'.
The cartridges come in three colour-coded strengths, Green=low, Yellow=medium, Red=high, depending on what material they're firing the fixings into - timber, building blocks, steel, concrete, brick etc. The cartridges are mounted on metal discs of ten, supplied in boxes of 100. They're fired by a captive piston. They're low velocity designed to be used at point blank range, unlike a bullet which is high velocity, has a much longer range and whose only purpose in life is to maim or kill..
In any event, only responsible people who read the makers instructions and abide by them should be using any nailer and that means ensuring there aren't any bystanders who could be injured.
Quote:
"During operation be careful that fasteners penetrate material correctly and cannot be deflected / misfired /broken out towards operator and /or any bystanders".
Unquote.
Looking at accidents with nailers, unsurprisingly perhaps, most are to the operators themselves, firing nails through their fingers or hands, (yet more proof of Darwin's theory of the 'non-survival of the stupidest'). But yes, the nails do look like bullets - why would they not do - they have to penetrate steel or concrete at close range:
https://www.spitpaslode.fr/en/Insulation/Nailing/P370_pFR_88222sharp0.htm#/lg=1&slide=0
People are probably more familiar with 'Paslodes'.
The PASLODE brand joined the SPIT company in France in 2002, and is marketed by the same sales network, offering high-quality nailers and staplers for the wood industry, carpenters, and roofers:
https://www.spitpaslode.fr/en/Insulation/Nailing/P370_pFR_88222sharp0.htm#/consumables
I think generally, on site, gas canister operated Paslodes are the favoured option.