Complex sentence: The cartridge cases have been used as parent cases for several other necked down and necked up cartridges and also rimmed 8x57mm IR and 8x57mm IRS versions are available for break barrel type rifles.
Split into simpler sentences: The cartridge cases have been used as parent cases for several other necked down and necked up cartridges. Also rimmed 8x57mm IR and 8x57mm IRS versions were developed for break barrel type rifles.