357 Herrett and IMR 4227, differences between manuals

[hornady308]

For those who don't already know, Hodgdon 4227 is no longer made. Only imr4227 is now available. Many of the best loads developed for the Herrett used the Hodgdon powder. Comparing the 2009 Hodgdon manual to the RCBS cast bullet manual number one, there are some large disparities in the published data for the IMR data. RCBS shows a maximum load of 28 grains of IMR for a 162 grain cast bullet and a max of 27 grains for a 175 grain cast bullet. Meanwhile, the Hodgdon manual shows a max load of 20.2 grains of IMR with a 158 grain jacketed bullet and 20.1 grains with a 170 grain jacketed bullet. This seems like a rather large difference in powder charges. I realize the cast bullet will generate less pressure, but I am surprised to see that it is that much different. Even the old Lyman 46th shows max loads with IMR of 20.5 wit 155 gr cast, and 19.5gr with 168gr cast. Any comments from the peanut gallery?

[ulav8r]

The different manuals were prepared by different people at different times using different lots of powder and different guns. Why should we expect them to agree exactly. Always start with minimum loads and work your way up till you are satisfied, and don't expect me to accept your final load as safe in my gun unless I work it up myself.

[hornady308]

I don't expect all the experts to have the same exact conclusions, but there's a significant difference between a max load of 19.5 gr vs a max load of 27 gr. That's a 72℅ difference in max.! The start charge in the RCBS manual is higher than the max Hodgdon charge. How can they be that far apart?

[northmn]

What are the cases and primers used to form the cases? There can be a big difference in loads on just cases. Loading manuals drive me nuts anyway.

DEP

[rking22]

Back in the day, when the 357Herrett was very popular with hunters and steel critter shooters, there were some VERY stiff loads published. Dupont(IMR) did some pressure testing and published their list of LAB TESTED loads, and they were much lower than the "normal" ;loads worked up by shooters with no pressure test equipment. I will have to look for my IMR data for the 357H to see what they showed for IMR4227, but I load IMR 4198 as that was the best power/pressure ratio from their testing. To my knowledge the IMR data was the first (maybe only at the time) pressure tested data for the Herrets. Those 27 gr type, "worked up" loads, stretched a lot of TC frames! Basically Dupont found that rifle powders in the 4198 realm worked better in the mini rifle cartridges, and the mag pistol powders did not yield the velocities desired until the pressures were above the TC Contender's design limits (roughly 40,00CUP with the 30-30 head size). Those pressures can be exceeded with smaller case heads, like 223 but we are talking 30-30 head size. Also *note* that IMR4227 and H4227 were(are??) NOT the same powder, different load data even when pressures were listed.

[ulav8r]

How can they be that far apart?

Post 5 explains it. Some of the loads were not pressure tested and others were.

[hornady308]

Thanks for the responses. I'll certainly stick with the more conservative data, but I'm still surprised that the manuals can be so different. The 357 Herrett uses the 30-30 Winchester case. The 30-30 is shortened, then necked up to accept a .357 bullet. The idea was to create a cartridge that would be extremely efficient when used in a 10" barrel.

[rking22]

Exactly , and it was. The 35 Rem was able to go a little faster but used more powder to do it. Deers nor steel critters could tell the difference, but the 35Rem recoiled harder in my hand. Actually the 357Max is probably the better nowadays, but I still like the nostalgia of the Herretts.

Also *note* that IMR4227 and H4227 were(are??) NOT the same powder, different load data even when pressures were listed in other cartridges.

[TCLouis]

Look at AA's load data . . .

Note it is with LP primer . . . Big difference in loading data when one does things like that

[curioushooter]

I am running into the same ridiculous problems with wildly different listed max loads for the 357 Herrett.

All using 200 grain bullets:

Accurate 1680 has a max load of 29 grains in the Hornady Load manual 8th ed.
Accurate 1680 has a max load of 34 grains in the Lee Load manual 2nd ed.

This isn't as bad, but the pressure data seems alarming to me.

IMR 4198 has a max load of 27.8 grains in the Hornady Load manual 8th ed.
IMR 4198 has a max load (and no starting load) of 28.2 in the current Hodgdon Load Data center with a PSI of 45,000 CUP!

Also, I have a G2 contender, which I understand are stronger and stretch less than the original Contender. They certainly have beefier sidewalls, so much that my Super 14" barrel's sights wouldn't fit on my G2 because they interfere with all that extra sidewall steel.

It's kind of a shame the 357 Herrett didn't catch on more. It is the same OAL (or can be easily) as 30-30, so I would think it would be a good candidate to re-barrel a lever action carbine, and I think the bottleneck would help with feeding. It would be a rimmed version of the 35 Remington basically.

[EDG]

.30 Herrett Contender barrels often have a .750 long section of bore with NO rifling just ahead of the chamber.
According to old wives tales this was done to reduce pressure in this non SAAMI wildcat. Variations in barrels can lead to variations in loading data.

[curioushooter]

Yea, no doubt, but 357 Herrett is basically at Contender cartridge, so not much variation in barrels.

The data makes no sense either. If 34 grains of AA1680 makes under 42,000 cup with a 200 grainer, then how can only 28 grains of IMR4198 get 45,000 cup with the same bullet weight. The powders are nearly the same density and burn rate. A grain here or there maybe, but six? That is about a 20 percent difference.

[curioushooter]

I'd pay somone with quickload to do a comparison of AA1680 vs. IMR4198 using 158, 170, 180, and 200 grain bullet weights for 357 Herrett.

[EDG]

See page 59 of IMR BROCHURE for .357 Herrett

https://www.google.com/url?sa=t&source=web&rct=j&url=http://pdf.textfiles.com/manuals/FIREARMS/imr_reloading.pdf&ved=2ahUKEwiv5oyP6pfZAhVH0VMKHSyXDXEQFjAFegQIBhAB&usg=AOvVaw0GdjFBvHK-FSlzRR01UKAI

[curioushooter]

Yea, I've seen that data. It's the same data basically that is found on Hodgon's online data center and Hornady load manual. Of Hodgdon's offerings, IMR4198 is clearly the best for 357 Herrett. The question is mainly about Accurate 1680. It is the same approximate burn rate, but more dense. You can stuff more in the case yet it runs lower chamber pressures. T/C did the work on it back in the day, and it is found in the Lee manual. However, in the Hornady manual the 1680 is capped around 28 grains like 4198 and gets the same velocity. Obviously seating depth may be a variable here, but on the face of it I have serious doubts about those 30+ grain 1680 loads.

[EDG]

Are you aware that H4227 was renamed IMR4227 and that IMR 4227 is the propellant that was discontinued.
No matter what you think of the data it is still your responsibility to work up a safe load.

[curioushooter]

I was aware that H4227 was discontinued. As far as I know, IMR4227 is NOT approximately the same burn rate. At least my Vitavouri 4th ed has them in quite different places.

[EDG]

I would not rely on VV for that information.
They don't know nearly as much about it as the people who manufacture it. The manufacturer has to run tests on the product everytime it is produced. VV might have tested it once or not at all. They could have copied the burn rate from anyone since they really have no responsibility for the results.

In any event the .357 Herrett is not a SAAMI standardized round. The factory chamber reamers could vary a lot. Any pressure test barrels may have chambers that vary from the production gun barrels and may be different from one lab to the next.


I was aware that H4227 was discontinued. As far as I know, IMR4227 is NOT approximately the same burn rate. At least my Vitavouri 4th ed has them in quite different places.

[curioushooter]

Do you think a 20 percent max charge difference can be explained by potential differences in chamber size? If it did we would be in a lot of trouble methinks. Most starting loads are 10 percent off max. If one were to apply this rule, in every load manual I've ever read and every powder company I've ever read, then you'd still be 10 percent over max if you went by the Lee manual data.

[curioushooter]

I have no H4227, the older burn rate charts have them very close. IMR4895 and H4895 are close, too, but definitely not interchangeable from what I've read.

Of course we need to work up the load, but you have to start sonewhere. It's why I brought it up.

I think folks are best off starting with Hornady's data. It makes sense, and they don't have a horse in the race, like the powder companies all do. And the data is free on the net.

[rosewood]

Are you aware that H4227 was renamed IMR4227 and that IMR 4227 is the propellant that was discontinued.
No matter what you think of the data it is still your responsibility to work up a safe load.

That was my understanding also.

H4227 is slightly slower burning than IMR4227, therefore, using IMR4227 load data would be safe with the slower H4227. If they rebranded IMR4227 to H4227, then the IMR load data would be unsafe.

Rosewood