In the U.S., Remington Arms Co. offered their side-lever single barrel in 28-gauge slightly before the Brothers P started marketting their 28-gauge doubles. It is an old wives tale that Parker Bros. invented the 28-gauge and it just won't go away. It was stated earlier this year in The American Rifleman!! The early Parker Bros. 28-gauges were built on the 20-gauge 0-frame. The lightened 00-frame 28-gauges didn't come along until well into the 20th Century.