Forums.NitroExpress.com

Let me know of any quirks you find in that Powley Computer I wrote. I'd be happy to fix them.

I've heard only good about the Oehler strain gauge system, and the RSI unit has a fine reputation as well. However, I can borrow a handheld 'scope from work; just add 4 resistors and a battery you're ready to read strain gauges. It's one of my "to do" items when I return to the US.

The way you describe for selecting powder is exactly how I see using the strain gauge. Getting true psi exactly correct is not necessary. I'm leary of reading "true" psi with strain gauges. Without the hydraulic calibration procedures used by SAAMI stations, I fear problems with strain gauge attachment, measurement of the barrel dimensions, etc. can lead to significant errors in calculating the true pressure. And what to do with those lovely octagon barrels I'm partial to?

Instead, you only need to see which of several powders gives the lowest pressure for the performance. Software tools, such as QuickLoad, reliably predict the fps feasible, they just can't sort out which powder will attain that performance. Use the s/w to predict fps, read the fps with a chronograph, and use the strain gauge to see which powder is best with respect to pressure.

Karl

Post Extras