gasp shudder hi pres. loads in 38 casework

[salvadore]

I've been shooting Elmer's and Skeeter's loads out of my S&W M-28 for a few years now, 38 spec. cases 6" barrel, 13/13.5 grs 2400 under 358156 Lyman and 12.5/12 grs 2400 under 358429 Lyman. I get apx. 1350fps with Skeeter's load and apx 1250 with Elmer's. Can anyone tell the apx. pressure I'm working at?

[376Steyr]

Are you using the lower crimp groove on the 358156 so the cartridge over-all-length is about that of a .357 magnum round?

[MtGun44]

I would say that since you are getting middling-upper level .357 Mag velocities
that you are shooting middling-upper level .357 Mag pressures. Since max
.357 pressures are about 40,000 CUP, and Hodgdon shows up to 1500+ fps
range for that kind of pressure with 158 gr jbullets, my guess would be
in the 28,000 - 35,000 CUP range, the Hodgdon numbers are for a longer
and unvented barrel, so you have to have higher pressured if you were
getting the same velocities from a shorter barrel with the cylinder gap.

.38 Spl max pressure is about 16,000 CUP and +P loads are about 18,000 CUP.

This is all pretty rough, but you have some reference points, with .38 Spl
+P loads running just under 1,000 fps in their longer unvented bbl, and full
power (with different powder, though) loads in the 1500 fps range with 40,000 ish CUP
numbers.

Clearly, due to the velocities you are getting you are well in to .357 Mag
territory. One thing in your favor is that typically boolits often will produce higher
velocities than jbullets for the same powder load, and at a lower pressure - although
this is highly variable depending on powder burning speed.

I wouldn't let any of those rounds find their way into an ordinary .38 Spl like a Colt
Police Positive or an older J-frame S&W, or even an older K-frame S&W. Not going to
blow up the gun but will be beating those guns pretty hard. No problems with your
big old N-frame, a very strong gun.

[bhn22]

With the last neutering of the 357 magnum, both loads probably exceeding current SAAMI pressure specs for 357 magnum. That said, a lot of the old "top" loads for 357 & 44 magnum exceed current SAAMI pressure specs. I shoot similar loads myself in L frames, and Ruger GPs. At one time I had a link to pressure tests on these loads, but they seem to have wandered off somewhere. I probably put them in a safe place so I wouldn't lose them.

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