Pushing the envelope with Herco in .38spl+P

[Walks]

I seem to remember a Guns & Ammo story story some 40 years ago about "Why not Herco in Magnum Handguns ?

Never seemed to go anywhere. I never tried it, simply because we used Unique in Magnum Shotgun loads.
But I'm always ready for new reloading info.

[ddixie884]

Larry, thanx for running these shooting tests. I am very surprised by your readings and the pressure of these Herco loads. I have been pushing this a little hard but holding back on loading a lot of rnds til after your pressure tests. I only have a few left and will fire them in a .357 Mag. I will no longer load more than 5.6 Herco under a cast 158gr in .38spl. It is really nice to have a friend to check the pressures for prospective loads. Thanx again for sharing your considerable know how with us here on this board.......

EDIT; After seeing this data I have more of an understanding of why the Herco data disappeared from the loading manuals. What I don't understand is why they didn't let it out that there was a problem with the pressure curve of Herco in the .38spl.

[ddixie884]

Examining my brass from from these loads with 6gr Herco under 158gr swc i see no flattening of the primers. They are rounded and domed but the firing pin indentations are very deep. I tried cycling other primers a second time and they still weren't as deeply indented 3 hits gave a similar indent. I wonder if the secondary spike came during the recoil of the hammer and caused this. Anyone have any input?

[Larry Gibson]

Post #16.

[tazman]

Larry---Have you tested any Herco loads for the 357 magnum?
I was wondering if there is a secondary spike in that cartridge also and if so how high.

[Larry Gibson]

Just one test of 7.5 gr Herco I had loaded under the 358477 in Winchester cases with WSP primers.

Ran 23,000 psi with only 2 of the 10 shots showing any secondary "spike" and then it was small....not out of the ordinary.

[fecmech]

Ah yes Herco. When I first started casting and loading in the 70's my mindset was max everything, go right to the top! The Lyman manual at the time listed 10.0/Herco with 358429 as max(in the .357)and that's where I went. I fortunately had a Ruger BH at the time and shot at least a couple thousand of those loads in it. We tried 6 in a S&W model 19 and had to pound the individual cases out. I guess it got a second pressure test. A later Lyman manual dropped that load to I think 7 or 8 grs but by then I had found 296 as my "magnum" powder.

[Pirate69]

Hi Larry,
That second peak is impressive. For comparison could you upload a pressure trace of one of the Remington 125s or something similar so we have a visual comparison of what you are seeing? Just curious, this is interesting to say the least.

Thanks

Perhaps there is a reason most newer manuals don't show data with Herco in the 38 SPL? Could be with the advent and now common usage of piezo-transducer and strain gauge psi measurements which give a complete "picture" of the pressure curve they've found some powders aren't really suitable in some cartridges. Yesterday ran a pressure/velocity test of Alliant Herco in the 38 SPL. Pressure was measured in a Conteder with 7.94" barrel via the Oehler m43 PBL. Fps are muzzle velocities. I used the Lee TL358-158-SWC because when seated with the case crimped in the 1st lube groove it gives about the greatest seating depth of any cast 150 - 160 gr bullet. The Cartridge OAL was 1.465". The bullets were cast of COWW + 2% tin, lubed with LLA and sized at .358 and weight 162 gr fully dressed. Cases were Winchester W-W with WSP primers.

I loaded 10 shot test strings of 5.4, 5.7, 6.0 and 6.3 gr of Alliant Herco (purchased last year).

We mostly expect the measured pressure traces (time/pressure curves) to be nice smooth lines going up to max pressure and then tapering off to muzzle exit. Many times they do do that. However, many times they don't. Particularly with straight walled cases we many times see a secondary "bump" in pressure. Sometimes these are sharp bumps and are many times referred to as "spikes". I have seen a lot of secondary pressure bumps and some spikes over the many pressure tests I've conducted. As of this date I've never seen any spikes like the ones I got testing the Herco powder in the 38 SPL.

Now, before anyone gets all excited and wants to insinuate the Contender test barrel and/or the M43 has some " noise" in it before and after testing the Herco loads I ran a test string of Remington 125 gr jacketed HP factory loads. The traces were as smooth as one would expect w/o any bumps or spikes. Previous test with that Lee bullet have also produced smooth traces with other powders. Thus the test equipment was good leaving suspect the Herco Powder.

The test results;

The 5.4 gr Herco load ran 1003 fps, SD 11, ES 27 fps, psi 19,100

The 5.7 gr Herco load ran 1070 fps, SD 15, ES 40 fps, psi 23,000

The 6.0 gr Herco load ran 1092 fps, SD 14, ES 42 fps, psi 23,200 ...... all the traces showed very high secondary spikes occurring during each shot. This is the first time I have ever seen a secondary spike in the trace exceed the psi of the primary chamber psi...... perhaps this is why we no longer see Herco data for the 38 SPL?

Attachment 269024

The 6.3 gr Herco load ran 1135 fps, SD 12, ES 30 fps, psi 25,200

A subsequent test of the same Herco in the 44 SPL under the RCBS 44-250-KT did not show the sharp spikes but just little secondary bumps in psi which, as previously stated, quite common. Thus, while the internals measured quite uniformly the very sharp and high pressure spikes with Herco in the 38 SPL are of a concern. Caution should be exercised if using Herco in the 38 SPL due to the high end +P+ range of psi in the 38 SPL along with the occurrence of the very sharp and high pressure spikes..

[Pirate69]

Well, here is another uneducated question. I do not have any knowledge of performing pressure traces. But I was wondering, how far down the barrel is the first and second peaks occurring and the timing? It may be on the posted test printout; if so, I don't know what I am looking at.

Hi Larry,
That second peak is impressive. For comparison could you upload a pressure trace of one of the Remington 125s or something similar so we have a visual comparison of what you are seeing? Just curious, this is interesting to say the least.

Thanks

[PAndy]

I am using some Herco and 800x in mild 357 cast rifle loads. The powders are available, so I am trying some. With the longer .357 case, even with 180 cast bullets, all I can observe is no signs of pressure concerns with either. I am down in the range of charge weights similar to those used in Mr. Gibson's 38 special test. Herco is decent but 800X is giving me better accuracy.

[ddixie884]

Well, here is another uneducated question. I do not have any knowledge of performing pressure traces. But I was wondering, how far down the barrel is the first and second peaks occurring and the timing? It may be on the posted test printout; if so, I don't know what I am looking at.

I'm not Larry and know nothing of pressure testing. I think that is happening while the bullet is still in the cylinder. Of course I could be wrong and maybe Larry will be along soon to give us some clarity......

[Larry Gibson]

If you look closely at the time/pressure traces you will see a black tick mark. That is muzzle exit.

After researching all previous tests with that test barrel I am suspecting there may be an anomaly with the strain gauge on that barrel as it has been on there for some time. Like most equipment sometimes something can be amiss and at first we don't catch it. I am going to be retesting it again with a load that previously gave good traces and also that Herco load again. If it proves out to be an anomaly I will replace the gauge, not hard to do but must be done correctly. Perhaps this next week.

[Silvercreek Farmer]

If you look closely at the time/pressure traces you will see a black tick mark. That is muzzle exit.

After researching all previous tests with that test barrel I am suspecting there may be an anomaly with the strain gauge on that barrel as it has been on there for some time. Like most equipment sometimes something can be amiss and at first we don't catch it. I am going to be retesting it again with a load that previously gave good traces and also that Herco load again. If it proves out to be an anomaly I will replace the gauge, not hard to do but must be done correctly. Perhaps this next week.

Larry, did you revisit Herco in the 38 +p?

[Carrier]

I have used it in 38/357 and could not get a decent load to work but do use a lot of Herco in 45 Colt and works very well.

[Larry Gibson]

Larry, did you revisit Herco in the 38 +p?

Have some ready to test. Just need to get to it. Was waiting on the +P factory loads to test at the same time(?). Looking at a test session perhaps next week. A new gauge is on the test barrel and it has proven good in the last test session.

[35 Whelen]

In for the testing results.

35W

[Silvercreek Farmer]

Have some ready to test. Just need to get to it. Was waiting on the +P factory loads to test at the same time(?). Looking at a test session perhaps next week. A new gauge is on the test barrel and it has proven good in the last test session.

Looking forward to it!

[ddixie884]

Any updates?

[pworley1]

Herco is a great powder, it's just not for everything.

[Larry Gibson]

Any updates?

No update, no excuses.

My bad. I was so focused on the BB and Underwood tests along with setting up the Ransom and Lee Rests I just plumb forgot I had the Herco 7.5 gr under a 358477 in 357 magnum cases loaded to test also. They were sitting right there on the shelf....still are......