Secondary pressure spikes

[HS]

A fellow experienced high secondary pressures while testing the Pressure Trace from shootingsoftware.com. The caliber were .204 ruger, and the 2. pressure ran in about 120 000psi according to the instrument.The first pressure spike was normal at about 50-60 000psi. He didn´t belive that there was a 2. high pressure, but in fact was something the PT picked up in the cable to the stain gauge...Exterior noise or something.The question is; Are secondary pressure spikes common, and are there reliable sources that they exist??? Are there any other pressure testing equipment that can show them other then the pressure trace from wwww.shootingsoftware.com?,RSI= Recreational software) The oehler M43 shows a secondary spike at the same time as the PT, but it is much lower. The cause of this can be lack of data points in the older system, because the pressure goes "staight up" fast and down again.Anyone that knows anything about this?
Arthur

 

[bglenn]

HS
I don't have a pressure trace unit. but from everything I read it looks to be real. A gun maker by the name of,hope i spell it right) Charley Sisk blew the end off 2 barrels, he is sold on the idea that the secondary spike is real. Go over to http://forums.accuratereloading.com/eve run a search on pressure trace and have a lot of reading. Good luck.
Glenn B.

 

[Asa_Yam]

Use of too slow a powder results in the bullet traveling up the barrel until it outraces the expanding gasses. The bullet stops, and the resulting pressure buildup causes the powder to burn faster. Pressure continues to build, until the bullet starts moving again.

See
http://www.sahunt.co.za/sahunter/reload/secondexplode.html
http://www.shootingsoftware.com/pressure.htm

Re: Instruments. Both the Oehler and the RSI do the same job as any recording oscilloscope. One factor that can account for the difference in plots is the sampling rate of the tool. A greater number of sample points displays a more complete picture of what is happening. Any event that occurs between sample points is not recorded.