The more I use computer modeling, the more things I find out that I never realized before.
One thing is that a 2” 32 H&R barrel is equivalent to a 3.5” barrel because the length of cylinder/chamber is added to the barrel length. That brings me to the next thing. A good amount of powder is burned in that short distance. Of course, it depends on the burn rate and density of the powder, but most non-magnum pistol powders will be almost completely consumed in a 2” 32 H&R Magnum revolver.
Looking at 6 gr True Blue as a control, and swapping other powders in GRT to get equivalent velocities and pressures I was a little surprised. Below is a comparison of the percent of powder burned in the barrel to reach approximately 1000 fps in 32 H&R magnum with an 85 grain XTP.
True Blue…..77.7%
N310………..100%
Titegroup…...92.3%
Bullseye…….93.6%
Unique………96.8%
AutoComp…..98.2%
What does that say? I don’t know. I just found it interesting. When you switch to powders like 2400, IMR4227, or H110, you lose a lot of powder out the end of the barrel, so it’s really inefficient, but that doesn’t negate the actual muzzle velocity. You just wind up paying for 30-60% of your powder that just goes to a big flame at the end of the barrel without an actual increase in performance.