Here we go
http://www.claytargettesting.com/study2/Study2.3.pdfFederal 3 dram 1 1/8 oz. Gold Medal
"The primer pressure peaks at about 1/10,000 second; the pressure then drops a bit before climbing again as the powder burns. In this case a peak of about 9000 pounds per square inch (psi) begins to drop at about 7/10 of a millisecond. The shot leaves the (30") barrel at about 3.5 milliseconds after ignition."
The pressure is down to about 500 psi by 2 milliseconds.
"The fanciful pressure curves of shooting magazines and gun-club talk, existing as they do largely in thin air, can take any shape that will buttress an argument. Let’s consider the ubiquitous “sharp jab vs. sustained push” descriptions. Proponents of slow-burning powders describe the benefits of low, extended pressure curves; users of Red Dot™ are advised to switch to Green Dot™ to enjoy the latter’s more gentle curve.
Let’s see how different these powders really are. Once-fired AA hulls were loaded with amounts of Red Dot and Green Dot to give about 1190 feet per second (fps) as measured by an inductive chronograph.
The following graph compares typical results for each powder.
The Red Dot pressure peak goes about 1500 psi higher than the one for Green Dot but with respect to time they are virtually the same, differing by no more than 1/10,000 of a second and generally far less.
I just don’t believe that anyone could tell the difference when shooting them. The people who experience Red Dot as a jab, Green Dot as a push, must be relying more on their own preconceptions than any differences in the pressure curves produced by the two powders."
PB is also compared.
