I read on another forum that some Canadian and Danish U.S. M-1917 rifles have a notch milled into the top of the receiver ring. Supposedly this was to allow their “long MG heavy ball and tracer ammunition to be loaded into the rifles with stripper clips (chargers)”. Can anyone substantiate this? I’ve looked through all of my reference material and can not locate any “long” loaded Danish .30-06 ammunition! I would think that if the cartridges were too long to fit the normal receiver opening, then they would be too long to fit the magazine as well.