358311 data above others

[hendere]

Hi everyone. I’m probably going to embarrass myself here, but why does Lyman always seem to list loads for the 358311 that are above bullets of similar weight? I’m talking about 38 Special and 357 Magnum. I’ve been guilty in the past of using that data for other designs of 158 grain bullets but have noticed that the powder amounts are pretty consistently above their listings for some lighter and sometimes similar designs.

[hendere]

One standout is 158 grain 358665 vs 160 grain 358311. Lyman Cast 4th edition lists the latter with two full grains more of 2400 but less pressure. The bases don’t look much different.

[Bazoo]

I've noticed that myself. Part of the difference is likely that the 358311 is a old bullet and was tested long ago. The data was likely somewhat in error because the testing methods they had were not as good as we have today. The 358311 data probably wasn't retested often once it was established except for the addition of new powders.

Same as the 31141 in 30-30. The data ain't changed for 40 years or more. Guess there are more interesting calibers to tinker with.

Another reason is that different bearing surfaces cause different pressures. So it may be that at the time the 358311 was tested, it's particular design did show less pressure. And of course seating depth plays a role. I don't have a 358311 example to measure to compare used case volume.

[Boogieman]

Lyman has not updated a lot of their old loads Another reason to start low and work up your loads

[rintinglen]

Look at the OAL of the two boolits and your question is partially answered, at least in 38 Special. The 358-311 is loaded to 1.550" while the 358-665 is loaded to 1.445". A tenth of an inch is significant in handgun cartridges. However, I am quite surprised at the .357. The 2400 data does not reflect any disparity in OAL; both the 358-156 and the 358-311 are loaded to the same OAL but the 311 load is nearly 11 % higher. There does not seem to be a consistent pattern. Overall, the 358-311 max loads are usually .2 to .5 grains higher, but some powders, notably AA #7, and N110 are clear exceptions.

However, I have great faith in the safety of the 358-311 data. It has been tested for many years, and were there a problem, somebody would have reported it by now. To be sure, top loads should be approached with caution, but with this mold, one need not feel he is the Beta tester.

[Forrest r]

Perhaps it's the amount of the bullet that's in the cast, case volume??? That bullet has an extremely long oal.

https://i.imgur.com/uIUZpPE.jpg

I've shot countless 1000's of those 358311's in the 38spl's and 357's. Very accurate bullet!!! Never worried about the load data and never had an issue in 10+ firearms.

The data that always got my attention with the lyman 3rd edition was the load data for the 358495 wc bullet in the 38spl's &357's.

[ABJ]

The 358311 that I have is a tapered bullet. The bottom drive band is all that has contact with the size die, resulting in lower pressure than most 38-158's I have. I do have to give it a little more pressure to make it equal to the other 158's.

Having said that, I do not know that other molds bearing that number will be the same. But compared to most in its class I think the bearing surface is less.

As others have said, that is an old design which may not have been tested with newer powders. I always look at the old manuals as compared to the new manuals and consider seating depth first and compare that and bearing surface before using the old data at the upper end.

Tony

[hendere]

Good info. Thanks Folks.

[smkummer]

Remember too that jacketed bullets reach peak 38 special at a lower velocity than lead.