unwinner and Wayne Dobbs-belated 38 SPL pressure tests

[Larry Gibson]

First of all, my sincerest apologies for the lateness of these tests. between a very ot summer here, high winds and illness in the family having me gone from home I wasn't able to get the testing done in a timely manner. However, I did manage to conduct the tests yesterday as i was home, the weather was nice with 75 +/- degrees and minimal wind.

Thesting was conducted using a 7.94" Contender barrel. The Oehler M43 PBL was attached to the Contender via a strain gauge. The test barrel is a 357 magnum barrel and using 357 reference factory ammunition test out compatible with the psi for that lot of factory ammunition. I first ran a test of my reference Speer 158 LSWC 38 SPL ammunition which consistently tests at 15,500 psi +/-. A test of that reference ammunition resulted in a 15,400 psi average. Thus all was well with the test system.

Wayne had sent some 147 gr WCs he had PC with a red PC. I loaded them in W-W 38 SPL cases over his requested 3.5 gr Alliant Bullseye load. I tested them with 3 different primers. OAL was 1.257". Test results;

Note; these psi's seem abnormally high for the load used. I am working on doing a retest so take these with a grain of salt.

With WSP primers the psi was 26,100
With CCI 500 primers the psi was 28,600
with Federal 100 primers the psi was 24,500

Wayne also sent along some Buffalo Bore Hard Cast WC (item 20D/20) non +Ps. The SAAMI MAP for standard 38 SPL is 17,000 psi and the MAP for +P is 20,000 psi.

The Buffalo Bore pressure tested at 20,100 psi.

unwinner sent some 358429s cast of 50/50 COWW/lead with just a "skosh of tin. They weighed out at 167.5 gr. I sized them at .359 and lubed them with 2500+. They were loaded in W-W 38 SPL cases, WSP primers with an OAL of 1.480". He had requested a test with 3.7 gr Alliant Red Dot. I loaded tests with 2.8, 3.1, 3.3, 3.7 and 4 gr of Alliant Red Dot. The pressure test results;

With 2.8 gr the psi was 16,800
With 3.1 gr the psi was 16,900
With 3.3 gr the psi was 20,000
With 3.7 gr the psi was 22,400
With 4.0 gr the psi was 25,700

Sometime, on a past thread or PM, someone had asked me if i had ever tested 5.0 gr of Red Dot under a 158 hard commercial cast bullet in a 38 SPL case. I had some so I loaded a test string in Speer cases with Remington 1 1/2 primers. The OAL was 1.50". The test results

With the requested 5.0 gr Red Dot the psi was 24,500

[Electrod47]

Mr. Larry,
Thank you for this. It answers some important questions for Red Dot users. My generic load for 148gr DEWS is 3.5 gt Red Dot same for 158 gr LSWC. The pressure test for the primers also is very helpful. I always wondered if I was risking a higher pressure. Thanks again.

[ddixie884]

Larry, you've done it again. It is so good to have real pressure data for all of these factory and hand loads alike. I really appreciate the tests you ran for me in the past and the new tests you are doing now. that BB HC wadcutter is dead on for +P and II'm glad to see it. Thanx for all you do...................

[dtknowles]

I want to add my thanks.
Tim

[Mk42gunner]

The pressures of the 3.5 gr Bullseye loads with 147 WC is astounding. Not too sure I want to run any of those through the old K-38 or Officer's Model Match.

Robert

[Outpost75]

Interesting test, as Lyman Cast Bullet Handbook, 4th Edition, 2010 on page 255 lists Saeco #052 at 1.265" OAL with 3.5'grains of Bullseye as 905 fps and 17,000 psi from 4" test barrel in Universal Receiver.

NOT disputing your results at all, but is possible that a soft DEWC in .38 Special brass, when fired in the longer .357 chamber might upset the base into the unsupported portion of the longer .357 chamber, so that it must squeeze down to enter the ball seat? Also have no idea on possible effect of powder coating vs. conventional lube on shot start. pressure or bore drag.

I would be willing to chip in with Wayne to cover cost of a dedicated .38 Special chambered barrel to fit your Contender frame to test these again. Could a 6-inch barrel work for you? If TC cannot provide a dedicated .38 Special barrel we can have one custom made, but I know John Taylor is booked a year out. Think about it and PM me.

[Wayne Dobbs]

Larry,

Thanks for running these tests for me (really all of us). I'm surprised by the numbers, since 3.5 BE with the 158 RNL is the original factory load. Along with Outpost75, I'm in for a .38 Special barrel to run this again. And, as stated by another poster, the difference in pressures from primer to primer is very useful. We'll revisit this one again.

[William Yanda]

unwinner sent some 358429s cast of 50/50 COWW/lead with just a "skosh of tin. They weighed out at 167.5 gr. I sized them at .359 and lubed them with 2500+. They were loaded in W-W 38 SPL cases, WSP primers with an OAL of 1.480". He had requested a test with 3.7 gr Alliant Red Dot. I loaded tests with 2.8, 3.1, 3.3, 3.7 and 4 gr of Alliant Red Dot. The pressure test results;

With 2.1 gr the psi was 16,800
With 3.1 gr the psi was 16,900
With 3.3 gr the psi was 20,000

Is 2.1 gr a typo, should be 3.1? If not, the pressure results make no sense to me.

[Larry Gibson]

Yes, that is a typo, thanks for the catch. I've corrected it, should have been 2.8 as stated in the explanation above of the loads tested.

[fivegunner]

Thank you Larry, I always enjoy Reading anything you post.

[Larry Gibson]

Ed and Wayne

I was also surprised at the pressure the 3.5 gr load of Bullseye produced. However, given the fact the pressure measurements of the reference ammunition, the other 38 SP loads tested and additional pressure tests of 9mm and 38 Super loads tested in the same barrel that day right after the 38 SPL tests all fell in line with what was expected. I ran the M43 systems check with that barrel last night and all was correct and functioning. I'm not inclined to think the M43 system was at fault.

I think Ed's idea's of the WCs may be very plausible. It might also explain the higher than standard SAAMI MAP of the Buffalo Bore WCs? There also is one other possibility in that I am human and never claimed to be infallible. It is possible I just plain messed up the load and there was more than 3.5 gr of Bullseye in them.

Before we get another barrel, I would like to conduct a retest if Wayne can send some more bullets? If so, can you send some both PC'd as before and naked so I can test with regular lube?

I would also load that load into 357 cases with the bullet seated deeper to the same OAL of the 38 SPL load. That would give the bullet support to the leade negating most, if any, riveting in the chamber.

Shall we try that first?

[Larry Gibson]

I've put a "Note" in the first post regarding the abnormalities of the 3.5 gr Bullseye load under the 147 gr WC.

[Stacts]

Great information. Thanks for the tests. Looking forward to anything you discover.

Also really makes me worry about my own loads...

[Jtarm]

Wow, I better dial down the measure a bit.

3.5 BE/DEWC is my use-in-bulk load. They drop 151-grains from an MP mould.

They don’t seem nearly as hot as Remington “FBI” ammo, RTP38S12.

Any volunteers to sacrifice a Buffalo Bore round and see what the propellant/charge is?

[Outpost75]

Larry, I still have a few thousand Remington factory 148 HBWC bullets and could send you some. The 50-yard groups from a ten inch twist Clark-Ruger PPC gun start opening up at 3.5 grains, but we got no skirt failures in a .38 Special chambered cylinder. Best accuracy was at 3.1-3.2 grains of Bullseye flush seated at 1.16" OAL in Starline brass with Redding Profile Crimp and Remington 1-1/2 or Federal 100 primers. 12-shot 50-yard groups were under 2 inches from the revolver and BSA Martini with Obermeyer .345 x .357 five groove 25" bull barrel with .38 AMU chamber and 1:20" twist with 10x Unertl would stay under 1-1/2" for a series of five consecutive ten-shot groups in a 50-yard tunnel off bags.

[Ford SD]

Note; these psi's seem abnormally high for the load used. I am working on doing a retest so take these with a grain of salt.

Could this be because these are "PC" coated ???????

[Jtarm]

What’s the throat diameter of the contender and bullet diameter?

[tward]

Larry, your posts never cease to amaze me! The depth and breadth of your knowledge and that of others on the forum have kept me and , I’m sure, others interested and safe in our ancient, but ever evolving hobby. A very sincere thank you, Sir! Tim

[Larry Gibson]

Larry, I still have a few thousand Remington factory 148 HBWC bullets and could send you some. .

I would certainly appreciate testing some of those Remington HBWCs.

[Larry Gibson]

What’s the throat diameter of the contender and bullet diameter?

By pin gauge measurement: bore - .347 and throat is .359. Groove slugs at .357. I sized the 147 WCs at .359 per request.