doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Measuring shotshell psi

Pressure is a function of force and area, either static or dynamic. There are three types of pressure, 1)absolute, 2)differential, 3)gauge. Of these three, which would best describe the pressure created in a shotgun barrel once a shell is fired? Then there are different types of gauges to measure pressure, strain, etc. Having said that, if one wanted to measure psi for their own reloads, how would such a guage be constructed? Thanks in advance.

Gauge pressure is the correct method. The gun barrel is exposed to atmospheric pressure, so there is no need for absolute pressure. Likewise, the barrel will, for our purposes, always be exposed to atmospheric, so differential is the same as gauge, in this case.

The current best way is to procure a strain gauge device, glue a strain gauge to your barrel (actually, a single shot like the H&R is a very fine candidate for a test gun), and follow directions for pressure testing. There are a couple of active threads on this subject.

Check this web site for details. One excerp is copy-paste below.

http://www.shootingsoftware.com/pressure.htm

"A strain gage is simply a small piece of polymer material with a fine conductive grid on its surface. As steel around the barrel expands the gage is stretched and current flow through the grid is altered. The PressureTrace module samples these current fluctuations (1 sample per 10 micro seconds/350 per shot), stores it in a memory buffer, then automatically downloads the raw data to the PC via a wireless connection where it is analyzed and plotted. Up to 10 shots can be overlayed and compared on screen at a time."

This seems to be one of the more popular solutions.

Great information,I found the other thread too. Thanks R, G.