You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "The K2 is capable of firing a rimless bottlenecked intermediate cartridge derived from what cartridge?" whose answer is .223 Remington.
Each document should contain about 30 words, and these documents should contain useful information.

Query: origin of rimless bottlenecked intermediate cartridge for K2 rifle
Useful Output:

Doc 1: Obviously assault rifles were introduced at the tail end, or shortly after, WWII and caught on globally quite quickly.
Doc 2: No. Both paper cases and case-less cartridges have failed the US Army testing over and over again. They do not hold up well enough in long-term storage.
Doc 3: The 6.5×42mm (official Tiperyn nomenclature .256 Rjinders) round is a rimless bottlenecked intermediate cartridge family developed in the the early 1950s.
Doc 4: A rimless bottlenecked intermediate rifle cartridge developed in Nazi Germany prior to and during World War II, specifically intended for development of the
Doc 5: Wikipedia seems to think that Caracal failed in their bid to S. Korea who went instead with a modernized DSAR-15PC as it was domestically produced.