Larry,
Yes, strain is measured only at the specific point the gage is mounted. For more data points, you would need to mount more strain gages...or as shown in that old drawing, more lead crusher coupons. P.S. but on a cylinder, one point will give an indication of stress distributed around that "hoop".

Whats interesting is the veiw by most here that pressure is what they want to know. Me, I want to know stress levels. I would rather to refer to steel data of various types and use known data along with the strain gage data and dimensional data from my guns to assess whether I wanted to shoot a particular loading in a particular gun. But it's certainly easier to just take general information on pressure limits of typical cartridges of a particular era and apply it to a gun that is of that era and say I'm close enough. But to be critical of a straingage measurement method, in light of the forgoing, is picking thru the pepper and ignoring much larger variables, IMO.

Last edited by Chuck H; 06/03/11 04:49 PM.