Manufacturers and designers talk about "built-in obsolescence" especially with respect to electronics etc.
Maybe they mean built in unpopularity, and that's what they are trying to achieve as they get people to buy a new mobile phone or 3d TV.
But to my mind its about a product becoming superseded by a superior design, which by nature will encourage consumers to desert their old product and flock to the new one.
To that end I guess I agree with point two of John Burns' definition above ie... 2. Outmoded in design, style, or construction: an obsolete locomotive.
I can't see where nearly any of the cartridges mentioned in this thread have been superseded because the basic design hasn't changed through the introduction of the later cartridges. They all still have a brass case of similar basic shape and method of ignition, propulsion etc.
In fact these older cartridges have been constantly upgraded by new components like better powders, bullets, loading techniques. In a sense they are a different product than they were when first released.
A 30-06 using a 190g LRAB, using a full charge of R17 is a different beast to that being loaded into magazines of all those Springfield rifles many years ago.
Obsolete, no. As to the 264; unless it has been superseded by a superior product I can't agree that it's obsolete either.
