Please Note: This is purely my personal take on this subject, and other people may choose alternative terminology.

When describing a deactivated weapon, you will often see terms like 'old spec', 'early spec', 'EU spec' and 'early EU spec'. What do they mean and what is the difference?

Back in the old days, generally speaking, it only required the opinion of one of the two UK proofhouses that a firearm was incapable of discharging a shot, to make it legal to own without a firearms licence.

This arrangement obviously had it's flaws, and so around 1988 I believe, a formal minimum standard of deactivation was agreed upon, and the three main areas or a firearm, namely breech, bolt and barrel, received a small proofhouse stamp to signify compliance with the new standard, along with a certificate of deactivation.

Come 1996 or thereabouts, this standard was concidered too lax when it came to dry-firing of smgs and loading of inert rounds into the cylinder of a revolver, so these functions were no longer allowed. This change only effected new deactivations, so at a stroke we had old spec and new spec. The spec did continue to evolve in minor ways over the next near 20 years, but nothing that really effected the functionality of the deactivated firearm.

That was until around 2015 when the EU got involved. It was decided that the specification was still a bit too lax, and that further measures needed to be taken to prevent a firearm from possible re-activation, effecting certain types of weapons more than others. So, now we have the EU spec. Old spec stayed as 'old spec', but 'new spec' became 'early spec' . Then in 2018, the EU felt that the 2015 spec didn't go far enough, so brought out the specification that is presently the current one. This created 'early EU spec' to go with 'EU spec', and the UK 'old' and 'early spec' .

Hopefully this will clear up any confusion!