This was taken from bolt action rifles expanded 3rd edition
{When the 721,722,and 725 were discontinued in 1962,Remington brought out the 700 series of high-powered rifles. Although the 700s have changed somewhat since that time, their actions, except for the trigger guard and magazine, are still almost identical to the original 721/722 actions. The 700s are made in two different lengths, for medium-and long-length cartidges.} The way I see it the 700 actions would have improvements to it as where the 721 would be an earlier action.