Chuck;
According to an older Machinery's Handbook chart 4140 when drawn to 1300°F has a Rockwell hardness of C20 & shows a yield strength of 85K & tensile of 110K. This puts the yield higher than the tensiles Greener tested. Remember though his tests were reported on in 1834. No doubt by 50yrs later these strengths were most likely improved & those really low ones totally weeded out.
Interestingly around 1981 I read an article in a "Machining Trade" magazine where the Ithaca Corp was reporting on their switch to "Roto-Forged" bbls for their shotguns. Sure was not even similar to Ads appearing in the Gun Rags, which stated what an expensive process it was but they adopted it in order to give the "Consumer" the best possible bbl they could make.
In this article one of the cost cutting advantages mentioned was they no longer used 4140, but a lower grade of steel, which due to the process ended up with essentially the same strength. This saved them many $$$ over the course of a year & labor savings of course amounted to much more. As I recall they had totally amoritized the switch in approx 2 yrs. Wish I had managed to save a copy, but was in the Co's magazine & was just showed to me as was well know I was a gun enthusiast.
