I've had cases oiled since the early 80s and they still go off. Quite a few cases are lacquered on the inside to prevent moisture killing the primer in storeage/on issue and it also stops oil getting through. I think you will find that if you read the letter of the law, a live primer in an inert round is not illegal. Some police forces will try and force you to assume otherwise but I think they are incorrect. Hampshire police will confiscate rounds with unstruck primers but I bet they wouldn't try and prosecute on it. BUT, in fairness to them, I was given an unwanted bag of small arms ammo. by a well known museum. But when I looked at what I had been given, I started to doubt myself if it was live or inert - can you tell the difference in your hand of the weight of a live 9mm or .380 round and an inert one - I bet not. And that changed my whole view of collecting inert cartridges - what difference does a struck primer really make if you try and, from the police point of view, compare it with the cost of a life should it fall into the wrong hands. So I went through all my hundreds of rounds that I know are inert and have had for 30/40 even 50 years and struck the lot. And even I was surprised at how many went off. Bear also in mind the cost of having a single round examined to confirm if it is live or not (perhaps 125) and you will see why the police more or less have to take a line which is not strictly within the letter of the law. Its a sign of the times we live in and there is no point sticking your head in a bucket of sand and hoping it will go away - it won't (but if you have to, try and find one of those really nice red buckets with 'FIRE' written on them, they're great!). The police have a difficult enough job to do as it is, we expect them to uphold law and order, safeguard us and our families but increasingly expect them to do it with diminishing resources and one hand tied very firmly up their, sorry, behind their, backs. Well, thats my view anyway - if you want, get a firearms certificate to collect live ammo, at least the authorities will know who & where you are and you'll have to keep it very securely under lock and key. Otherwise, do what you can to help the authorities to do a difficult job and accept that we, currently, have a freedom that many European countries do not have in respect of collecting inert ordnance.
Here ends this evenings sermon
Dave