One of the guns I’d brought to Namibia was a muzzle-loading rifle, to hunt warthog.  When asked how many “cartridges” I’d brought, the police officer was flummoxed by the concept of a rifle that didn’t use them.  He had never before encountered a muzzle-loader and his English wasn’t up to the task of understanding my explanation.  In the end I just told him how many “bullets” I’d brought and that satisfied him.  On the way out, and equally polite lady officer asked how many “bullets” I was taking out of the country, so I told her the same thing. 

On return to the USA, I had a less amusing encounter with an ignorant Customs officer who checked the rifles in.  My principal rifle this trip was a Husqvarna made in 1944 in Sweden (see below).  In Europe the practice is to stamp the serial number on the barrel, not the receiver, because the barrel is the “controlled” component.  This clown was mightily upset and threatened to impound the gun because it wasn’t “legally” marked.  I forbore to argue the point with him: he was armed (with a gun as well as self-righteousness) and it would have done no good to point out the differences in practice; or, that since my rifle pre-dated 1968 (when US law mandated serialization), it needn’t have had a serial number at all.  In the end he said he would “be a nice guy” and let it pass through, but warned me to “…get the serial number engraved on the receiver.”  I eventually did so not because I had to, but to avoid similar encounters with law enforcement officers who don’t know the laws they’re supposed to enforce.