Quick load

[Jager]

As @RegionRat notes above, the burn rate of a powder is dependent upon multiple factors. So much so that it's really a very, very crude measure. Context matters. And a Burn Rate chart strips away all context.

Likewise, I'm not sure there's any evidence that a powder charge that is completely burnt inside the bore is inherently more accurate than one where some of that powder is wasted.

A real world example... .30 BR is the most common cartridge found along the line at a SR Score Benchrest competition. QL has 34.0/H4198 behind a Berger 115 gr (COAL of 2.300" and case volume of 40.25 gr) making right at 2950 fps @ 59K psi. That's a moderately compressed load, and many guys are actually running a bit hotter than that. Out of a 23" barrel... just over 97% of powder is burnt.

Add another half grain of powder and the load is pushing towards 3000 fps, with an even more compressed load. Amount of powder burnt inside the barrel is slightly higher (because of the higher pressure) but is still under 98%.

Most of us are happy to waste a few grains of powder out in front of our bench if it means an extra X or two.

FWIW, you can build a Propellant Chart inside QuickLoad which provides some interesting insights into how various powders compare to each other.

 

[Retired shooter]

Thank You guys.

Seems like when you start using these type of programs it generally make a person start thinking of other ways it affects what, we got the program for. Answers one question, and creates 10 others.

Thanks to all.

 

[MagnumW]

If you look at the pressure time curve you want that area maximum size under the curve and there are so many ways to tweak that curve any of which could burn powder sooner or later for greater speed. To get that big long fat curve from slow powder we live with it taking a certain longer barrel length to burn it all.

 

[Retired shooter]

Thank you Magnum.

More of the question answered.!