This is a very long length powerpoint (73 slides) that discusses sound, barrel length, caliber, suppression, how to measure sound, background effects, etc.
http://www.larsondavis.com/ContentStore/mktg/LD_Docs/Firearm_Sound_Briefing.pdf
Pretty good summary of the math and practical application of how sound created by a shot being fired affects the observer and the shooter. Some experimental data is included using the 5.56 as a baseline for various examples. Apparently prepared for U.S. military as a contractor that sells sound measuring devices from what I can gather.
http://www.larsondavis.com/ContentStore/mktg/LD_Docs/Firearm_Sound_Briefing.pdf
Pretty good summary of the math and practical application of how sound created by a shot being fired affects the observer and the shooter. Some experimental data is included using the 5.56 as a baseline for various examples. Apparently prepared for U.S. military as a contractor that sells sound measuring devices from what I can gather.