Chronographed - Underwood 38 Spl +P “Keith” 158 gr SWC

[RJM52]

Here is another good link that includes the BB loads...comparing it to several others...

http://smith-wessonforum.com/ammo/14...aph-tests.html

[ddixie884]

Oh well, I’ve been wrong before. I’m really surprised that the BB and the Underwood are both at 28,500psi. I wouldn’t shy away from using any of them if I need them but I would like 24,000psi better. Thanks to Larry.we have real figures to work with.

[RJM52]

Doesn't really bother me at all as it is well south of 9mm, .38 Super and .357 Magnum and right in that sweet spot velocity wise that balances performance and control.

[ddixie884]

Larry, have you ever done any pressure testing on 158 grain Boolits and 38 special at 5.5 and 6.0gr unique?

[derek45]

Very interesting thread, thanks Larry

[Larry Gibson]

Larry, have you ever done any pressure testing on 158 grain Boolits and 38 special at 5.5 and 6.0gr unique?

Yes, I have.

[Larry Gibson]

Larry, have you ever done any pressure testing on 158 grain Boolits and 38 special at 5.5 and 6.0gr unique?

Yes, I have. The 5.5 gr Unique load under a soft cast HP'd 358156 seated to front groove in Winchester 38 SPL cases is my standard FBI LSWCHP load duplication. I produces the same velocity as the older original Winchester load I carried for LE duty back in the mid/late '70s. Pressure wise, it runs at the top end of SAAMI's criteria for +P 38 SPL.

[RJM52]

What are you running for velocity..950 from a 4"?

[ddixie884]

I’ll bet you guesstimated that within 20fps. Of course I could be wrong.

[RJM52]

The 1980+- vintage FBI load from Federal, Winchester and Remington generally runs between 875 and 950 from a 4" barrel. I was with Allan Jones one day at the Dallas P&R Club as he was testing a new batch of Federal (I believe) ammo. It was 950 on the nose which was the highest velocity I've ever seen for that load.

From what I have read all three makers made bullets of different hardness levels and HP shapes so expansion and penetration varied. There was also lot to lot differences from the same maker...

[Wayne Dobbs]

No, I have not tested any similar Buffalo Bore loads.

Larry,

You may recall I sent you 10 of the standard pressure BB DEWC loads last year. They were not standard pressure, as advertised.

[ddixie884]

[QUOTE=Wayne Dobbs;5594984]Larry,

You may recall I sent you 10 of the standard pressure BB DEWC loads last year. They were not standard pressure, as advertised.[/QUOTE

Yes, those were +P but not +P+ like the SWCs..........

[JRD]

I'm a little late to the party to start paying attention to this thread. Larry, yours is the first pressure testing of Buffalo Bore and Underwood 38 Special +P loads. I have always wondered how they achieved such ballistics and stayed within SAAMI pressures. Apparently they don't because the laws of physics still apply.

38 Special SAAMI MAP is 17,000 PSI
38 Special +P SAAMI MAP is 20,000 PSI

These companies are apparently selling ammo loaded to 28,500 PSI as 38 Special +P but it's actually 40% OVER SAAMI +P pressure.

I don't doubt it's good ammo- if shot in a 357 Magnum chambered gun. I sure wouldn't shoot this stuff in a gun that's not a 357. This ammo can't be good for the life of an alloy frame S&W 637/642/442. I'd even refrain from using it in a S&W Model 10. Someone earlier commented that they wouldn't use this ammo in a gun that's not also chambered in 357 Mag. Just bear in mind that not all frames of a given size are actually the same. For instance a S&W K frame Model 10 and a K frame Model 19 frame are not the same in terms of frame strength.

[TD1886]

My report to ddixie884 with the info Silvercreek Farmer requested;

Finally got it done!,, Many personal difficulties the lat 8 months which is just the way life is. Then when I did start testing a couple weeks ago had technical problems with the test barrel/gauge. After a couple attempts to discover the problem I finally just removed the old gauge and installed a new one. That fixed the problem. Testing went well yesterday.

I first ran a "reference factory load" [Speer 158 lead SWC] through the test barrel with new gauge. That ammo (have several boxes all the same lot) Has proven to be quite uniform giving average psi's of 14,300 - 14,600 psi. The psi measured yesterday was 14,400 which was exactly the same psi as the old gauge had give with the last test a year+ ago. Thus all was well with the new gauge. I then ran 10 rounds of my standard 357 Magnum load through it. That load previously averaged 35,000 psi +/- and yesterday it measured 35,600 psi, well within the test to test variation of that load.

I then tested both of the Underwood factory rounds you had sent to me. Both proved to be excellent performers giving very low ES/SD for velocity an pressure. Accuracy at 50 yards was also excellent. I was using the test Contender (7.94" barrel) in a Ransom rest. Ambient temp was 75 degrees with a humidity of 15%.

The Underwood 158 Hardcast Keith +P load ran 1336 fps with ES/SD of 16/6 fps. The psi averaged 28,500 with an ES/SD of 0 !!!! yes, that was ZERO variation in pressure, all 10 pressures measured the same....thus the very low velocity ES/SD. Accuracy at 50 yards was a, just under, 2" group.

Cartridge specifications:
Starline 38 SPL +P cases
Unkown SP primer
5.5 gr of a very fine ball powder
161 gr PC'd SWC bullet, BHN measured on base and nose at 17-18, .3575 - .358 diameter
Cartridge OAL; 1.423"


The Underwood 158 LSWCHP load proved to be just as goo running 1314 fps with an ES/SD of 28/9 fps. The psi averaged 28,400 with an ES/SD of 200/100 psi. Accuracy at 50 yards was just over a 2" group.

Cartridge specifications:
Starline 38 SPL +P cases
Unkown SP primer
8.5 gr of a very fine ball powder
158 gr PC'd SWC bullet, BHN measured on base at 8, .356 diameter
Cartridge OAL; 1.431"

Note; the PC on both bullets was a dark blood red.

No comments on whether they should be shot out of 38 Special revolvers??

[Larry Gibson]

No comments on whether they should be shot out of 38 Special revolvers??

My comments in post #33 apply to the Underwood +P loads tested as well as the Buffalo Bore +P loads.

[TD1886]

My comments in post #33 apply to the Underwood +P loads tested as well as the Buffalo Bore +P loads.

Wouldn't you agree that there are 38 Special revolvers out there that couldn't take a steady diet of those loads? Makes me wonder how they came about.

[Larry Gibson]

Begging your indulgence, I prefer not to get involved in that end of the discussion.

[TD1886]

Begging your indulgence, I prefer not to get involved in that end of the discussion.

Okay good enough. In a sense you answered my question.

[RJM52]

"Just bear in mind that not all frames of a given size are actually the same. For instance a S&W K frame Model 10 and a K frame Model 19 frame are not the same in terms of frame strength."

TD...just wondering where you got your information...

Do you have information that a Model 64 frame (.38 Special) and Model 65 frame (.357 Magnum) have gone through a different heat treating process?

Thank you...Bob

Bob

[TD1886]

"Just bear in mind that not all frames of a given size are actually the same. For instance a S&W K frame Model 10 and a K frame Model 19 frame are not the same in terms of frame strength."

TD...just wondering where you got your information...

Do you have information that a Model 64 frame (.38 Special) and Model 65 frame (.357 Magnum) have gone through a different heat treating process?

Thank you...Bob

Bob

Bob I didn't write that first sentence you have there. But since you posted it I'd like to say that they do heat treat the 38 Special and 357 Magnum cylinders differently. I didn't use to think so, but was told different. My argument was they were going to send the cylinders through the heat treating oven so why not both. I was told I was wrong. I never worked in that process I don't know.

I get my information from a lot of source and have good number of friends in the industry. I don't rely on the internet for any of it.