17 January 2017
My pressure testing of the 38 S&W is incomplete at this time. I've pressure tested 2 loads of 38 S&W with an Oehler M43 using a Contender .357 barrel. The extra length of the 357 chamber also approximates the cylinder throat length. Granted there is no barrel/cylinder gap but that means the measured psi will just be a bit higher in the Contender barrel. Given the nature of strain gauge psi measurement it requires about 7 - 9000 psi to get a measurement. SAAMI MAP for the 38 S&W is 14,500 psi (transducer/strain) which is intended for solid frame guns. As a reference the 38 SPL has a MAP of 17,000 psi. Most all factory 38 SPL psi's I've measured run 14,500 to 16000 psi.....that's a typical fudge factor between the SAAMI MAP (Maximum Average Pressure) and actual measured factory psi's. Contrary to popular belief most factory ammunition is not loaded to SAAMI MAP.
As to my tested loads; while 38 S&W cartridges do not chamber I used R-P match 38 SPL cases trimmed back to 38 S&W length. They are the thinnest back to the web of any 38 SPL cases I've found cut back to .38 S&W length and are very close in dimension to modern 38 S&W cases. I loaded the same load as I load in 38 S&W cases using 2 gr Bullseye under the 105 gr Lee SWC and the 150 gr Lyman 358477 with a CCI SPP. After 10 rounds tested with the Lee bullet I got no psi measurement. That means the psi was less than the required 7 - 8000+ psi needed to put a strain on the barrel to measure. After 10 test shots of the 358477 bullet there were 2 very low erratic measurements indicating barely any consistent strain on the barrel at all.
Thus I have had no problem shooting either bullet with 2 gr Bullseye in either of my revolvers. I prefer the Lee bullet simply because it uses 2/3 the alloy per shot and hits to point of aim at tin can distance.........
If you'd like to send me some of your bullets or your friends bullets and load info I'd be glad to pressure test them?
Concealment is not cover.........