5 mm Rem mag October 30, 2026August 5, 2013 by ammobuyersguide 5 mm Remington Rimfire Magnum Designed in 1969 never popular, discontinued in 1973
.22 WRF October 30, 2026August 5, 2013 by ammobuyersguide .22 Winchester Rimfire .22 WRF introduced in 1890 identical to .22 Remington Special (has a roundnosed slug)
.225 Win October 30, 2026August 5, 1964 by ammobuyersguide .225 Winchester Introduced in 1964 replacement for the .220 Swift replaced by .22-250 Remington