Lyman data questions and 357 magnum

I've been working up some loads and wanted to get some insight from the brain trust here at CB. Recently I've started to feel that maybe Lyman data is hotter than other sources in general, wether it's their cast boolit data or their jacketed data. In the cartridges and bullets I reload for, they always seem to have the highest max loads other than maybe one or two exceptions. Has anyone else noticed this or am I crazy?
I always start low and work up and I've gotten to where I'm happy with most of my loads but there are one or two I'm not sure of.
I reload 38/38+p 357 magnum and 9mm.
Let's take their 38 and 38+p data for example. Right now I'm using HS6, HS6 isn't listed for a 158 SWC but it's listed for a 155 grain SWC and a 160 grain RN. Both of those boolits have max loads of 6.7 grains HS6 and both are supposedly standard pressure 38 special.
Other sources indicate 6.3 grains as a max load, some older Speer data indicates 6.7 grains as a max load for 38+p but anything above 6.3 is in the +p range.
Another example are the same boolits using Win 231, Hornady lists a max load of 4.4 grains, Speer is around the same with 4.7 being a +p load. Lyman lists 4.7 as a max load for standard pressure and 5.2 as +p.
I don't load my 38s that hot since they're for plinking, although I do like the 6.7 grain load as my duplication FBI load. Loading 357 Magnum is where the Lyman data really becomes an issue for me.
Lyman does list HS6 under a 158 SWC in 357 magnum. It starts at 9.2 and goes to 10.2 grains. The 155 grain starts at 9 and max at 10. 160 grain round nose goes from 8.5 to 9.7 grains.
I've worked up and started slow using both lubed and powder coated 158 grain SWC from Missouri Bullets. I've intended this load to be a woods defense and possible hunting load. I have not found any other source for cast bullets at magnum velocities but with their max data being much higher than other sources I'm wondering just how safe their data actually is.
If we go back to 38 special, hodgdon lists 6.3 grains as max for a 158 SWC and 6.2 max for a 158 Hornady XTP. For 357 magnum they list 9.5 grains HS6 as max for the 158 XTP. I know it's not all apples to apples but this tells me a 158 cast bullet should be safe to push around 9.6-9.7 grains in line with Lymans load for the 160 grain RN. Hodgdons data for lead/cast is a joke in 357 magnum so its not really comparable.
Like I said I know it's not all apples to apples but I can't help but feel 10.2 grains HS6 might just be a little too hot under a 158 grain boolit.
I did slowly work up from the 9.2 start (actually lower than start, Hornady lists 8.2 max for their swaged 158s) and worked up to 10 and 10.2
I couldn't notice too big of a difference between 9.5 up through 10.2 other than primers. In my Ruger Security Six even factory 357 loads seem to have flat primers, but the 10 and 10.2 loads seemed to be much worse for some reason. Extraction was just fine, recoil was about the same, but something about those primers seemed off to me.
I'm sure 9.5-9.7 will be just fine for my intended purposes and I've decided to back down to those levels. I'm just wondering if anyone else has noticed that Lyman data on average seems to be hotter than most sources?
Even with jacketed bullets in 9mm (124 and 147 grain) they always have the highest max loads. Their loads are all listed in CUP rather than PSI too. I had to back down on some of their 9mm loads as well.
Is there any other cast boolit data out there that can be compared to the Lyman cast book? I like to have multiple sources which is easy for jacketed bullets, not so easy for cast boolits. The closest I've found is the Lee 2nd edition, with magnum powders like 2400 and 296/H110 their data is very close to the Lyman data, other powders are way off. Lee (and Hodgdon) list 7 grains of HS6 as max for a 158 swc, which is a glorified 38 special load. Hornady lists 8.2 which is much better. But Lyman is the only source I can find that goes that high with HS6 and cast boolits in 357 mag.
Maybe it's just that their data for the 160 RN is a better match for the 158s I have? I'm not looking to push it to unsafe levels and my plinking ammo is no where near max. I just want to make these boolits hit as hard as possible since they're for serious use. I plan to try 2400 next, maybe Accurate #9 if 2400 isn't available, since I'd have other data to compare it to and can get to where I want to go without all the second guessing.
Has anyone pushed HS6 that far with a similar boolit in 357 magnum and if so what was your experience?

I think most of the reason that we find one source of load data being a bit different than another is likely the type of firearm or action used to conduct the testing and of course, the barrel lengths. If the handgun tests are done with a universal action that has no cylinder gap, there will be a decent amount of difference. Certainly with rifle data, some is done with universal actions vs others with actual barreled rifles. The differences in powder lots can also contribute to variations in data.

I am not 100 % positive, but I have read that Lee likely purchases and uses data developed by others. I have noticed that lots of the Lyman data is carried over from many years past. Likely the reason that much is still listed in CUP vs PSI. My older Speer #8 & #9 manuals certainly do seem to give a few warmer loads than most today.

HS-6 is the same powder as Win. 540 in case you find some useful data that lists that Win. powder.

I have not worked with HS-6 all that much with handgun loads other than with a really heavy bullet in a .44 Special Bulldog. Mostly use it for heavy duck/pheasant loads in my 12 gauge.

I've always felt Lyman data was right on for their max loads. Course... that's what a max load is, the max they have found with their equipment and components. I usually use Lyman data for all of my needs, unless I am using an RCBS bullet and I use RCBS data for that specific bullet.

There was one time that I had a Lee TL452-230-TC that their data wasn't good, at least for me and my bullets. They list their bullets as 230 grains, mine dropped at 238. I was using WSF powder, and their starting charge out of the 4th Edition Handbook was more like a +P. I ended up backing down, and came up with a good load of 4.8 grains WSF with OAL of 1.170 (I checked my manual to make sure before posting it).

Of course with that, I have a heavier bullet. It's likely my powder was on the more energetic side of lot-to-lot variance than theirs was too.

I would love to get a peek of the Speer #8 manual! That manual is legendary, I mostly want to try some 38+p loads from #8 for use in my 357. I have way more 38 cases than I do 357 but that's a whole other topic.
You guys both made some great points though, first and foremost I'm using close but still different components. I'm using commercial cast bullets so while similar they're not exact. I wish I could get set up to cast and I definitely plan on it in the future but right now it's just not an option for me.
That might explain why my 158s are working better with the data for their 160 grain RN?
As for my 9mm loads I'm using pulled/blem HST bullets, no data even exists for those bullets so also different components. I always start low and work up but it just felt odd backing down from their max loads while other companies "max" loads just weren't enough. Some of Hodgdons max loads are a good example, 3.7 grains 231 is a "max" load for a 158 swc.

Lymans load data is almost always pressure tested before it is published. If you see actual Lyman data that shows a pressure listed, it is because they did that. None of this "none of this data exceeds the SAAMI listed pressures for (whatever) caliber. Some companies hired Lyman to pressure test their designs as well, Lyman started listing other manufacturers designs in their handbooks some years back as well. There were a number of variations including pressure testing in the Universal Receiver, and chronograph data using actual firearms, which would be listed in the remarks section.

double post

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Originally Posted by Magnum0710

SNIP>>>

I just want to make these boolits hit as hard as possible since they're for serious use.

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Do you have a chrono?
While it is good to have more than one source for data and cast boolit data is kind of scarce, but a Chrono is more important for what you say you are doing.

With that said, here are a few manuals with cast data.
I really like Nick Harvey's practical reloading manual.
RCBS #1 cast bullet manual.
Ken Water's Pet loads has a bunch of cast data.
Oh, I recently bought a paper Vihtavuori reloading manual, they list cast data for their powders, if you ever use them?

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Originally Posted by Magnum0710

I would love to get a peek of the Speer #8 manual! That manual is legendary, I mostly want to try some 38+p loads from #8 for use in my 357. I have way more 38 cases than I do 357 but that's a whole other topic.
You guys both made some great points though, first and foremost I'm using close but still different components. I'm using commercial cast bullets so while similar they're not exact. I wish I could get set up to cast and I definitely plan on it in the future but right now it's just not an option for me.
That might explain why my 158s are working better with the data for their 160 grain RN?
As for my 9mm loads I'm using pulled/blem HST bullets, no data even exists for those bullets so also different components. I always start low and work up but it just felt odd backing down from their max loads while other companies "max" loads just weren't enough. Some of Hodgdons max loads are a good example, 3.7 grains 231 is a "max" load for a 158 swc.

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have you weighed those 158 grain bullets. bullet variation is real.

but teh reason the powder charge for the microscopically heavier bullet works better for the bullets on hand is merely a matter of "it make the bullet seal better in the barrel". Or you bullet has a slightly longer seated length then others do.

If you have it available to you, the "The Complete Reloading Manual for the .357 Magnum" is a decent resource for viewing quite a few recipes in one place from a multitude of Mfg's, including Lyman.

I think, for the Missouri bullet you have, the Lyman manual is a poor choice. Your bullet is of unknown heritage and is not closely related to most of the Lyman bullets. The information in the Hodgdon manual is most relevant as they show the same/similar generic machine cast .357 swc as the bullet you have.

Although the weights are the same the depth to which your bullet seats in the case can be considerably different than some of the others.

Perhaps the bullet manufacturer could provide guidance on how to load their product?

You have to remember that the manuals are guides, not the last word. If using things exactly as listed you can be be a little more certain but.....

One thing a lot of folks don't realize or follow is the seating depth of the bullet used has a huge influence on pressure. It's well stated years back that seating a bullet .070" deeper in a 9mm case can almost double the pressure under certain conditions.

With a 38/357 you have a lot of published info that should get you close. If trying +P level loads go in small increments, say .2 grain and check under various temperature conditions. As an aside you'll see most +P loads are only .3 or .4 grs higher than the standard load at max pressure in most manuals.

The Lee manual is another decent reference to have.

Thanks everyone, I'll try to answer everyone in one go. I don't have a chronograph but I plan on getting one down the road. I have alot of other equipment I need to build up first, my set up is super basic right now.
Haven't used any VV powders yet, only two shops in my area sell reloading supplies and its all Hodgdon and Alliant powders. I'll look into the other books too and see what they say.
Being that it's not the exact bullet in the Lyman manual that's probably why, the max load wasn't necessarily dangerous but for some reason it felt wise to back down a little.
Hodgdon data for cast bullets is a joke and I'm surprised they don't know better. I haven't checked their data for say 2400 or Accurate #9 but their data for HS6 is laughable. 7 grains is a max load for 357 magnum at 15,000 psi, 6.3 grains is the max load for standard 38 special. Alot of people use 7 grains in a 38 case to duplicate the old FBI load. I personally think 7 grains is a little too much unless it's being shot in a 357 revolver but my 6.7 grain +p load is close enough and I woukd trust it in a 38 only revolver. Hodgdon data is for CAS. I have some older Hornady data for their swaged bullets, 8.2 grains HS6 is the max load for 158. That one is a decent midrange load at least, Hodgdon cast data is a joke. The Lyman data wasn't unsafe with my particular bullets, just felt the max load was a little too hot is all. The data worked just fine.
I do try to get as close to OAL as I can, it's hard with cast bullets cause it really depends on the crimp groove. With my HST bullets I try to set those to factory length if not a little bit longer. I guess I'm just going to have to test out my cast loads in different mediums and see if I like their performance.

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Originally Posted by Magnum0710

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Hodgdon data for cast bullets is a joke and I'm surprised they don't know better. I haven't checked their data for say 2400 or Accurate #9 but their data for HS6 is laughable. Hodgdon data is for CAS.

I do try to get as close to OAL as I can, it's hard with cast bullets cause it really depends on the crimp groove.

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If you scroll down the page past the CAS loads Hodgdon website shows Accurate No. 9 @ 32,200psi and 1,255 fps. Ramshot True Blue is @ 34,800psi and 1,464 fps. Those loads are no joke.

I've done a lot of actual pressure testing of numerous cartridges in numerous firearms the last 15 years. I've not found any of the Lyman data in the current manuals to be "hot" as in giving excessive pressures. Yes, some do dance right up to the SAAMI MAP level which is fine. What i really like about the Lyman Manual's is they have actually pressure tested and list the pressures they obtained. As mentioned though, there are many variables that effect pressures. Even if you were to exactly duplicate Lyman's loads (I have numerous times) you'll probably have different lot numbers of the cases, the powder used, the primers, a different bullet lube and a slightly different alloy.

All those variables can make a difference. I have not pressure tested any 357 Magnum loads with HS6 as that powder just hasn't come up on my radar with that cartridge.

I might add that most all of the older 357 Magnum factory cartridges I have pressure/velocity tested have ran 25 - 30,000 psi with attendant lower velocity. However, Lyman's listed maximum load of Blue Dot, 2400 and H110 under the 358156 cast bullet run very close to the SAAMI MAP of 35,000 psi. My standard 357 Magnum level load for my Ruger Security Six w/6" barrel is 14 gr of Alliant 2400 under the 358156. It's right at 35,000 psi and runs 1335 fps out of the Ruger. Although 10.3 gr of Blue Dot under the 358156 is seeing more use these days.

I will comment on several items.

One item is a concern with focus on OAL when trying to run up to book max using any bullet other than the exact one listed. Individual bullets can have significant length differences leading to different seating depths if you keep COAL the same. Increased seating depth can cause increased pressures well over published data. Variations in seating depths is one reason that different bullets can have different maximums in published data.

Second item deals with apparent confusion in available data.

Some of the confusion is caused by "reality" where a specific combination really will run with a higher pressure than some other "similar" combination. Unless you are running the exact bullet listed at the exact AOL listed, it is probably not a good idea to "cherry pick" loads with the highest allowed charges where other loads are shown at near max pressures with a lower charge.

Other confusion is caused by "stuff" with the data. It is not hard to find differences in allowed charges for the same exact bullet where both sources pushed up to near max pressures. This is probably just the result of one test combining factors that push up recorded pressure (fast lot powder, tighter chamber, measuring inaccuracy, different primer, smaller case capacity, etc.) more so than the other.

There is also "stuff" where the source is not really reflecting complete and/or actual data. For example, some of the Hodgdon on-line data currently listed for a 10" barrel is actually old Western data that was originally shown as being for a 6" barrel. Also, given my discussion of bullet lengths, load data for anything similar to "158 gr cast SWC" without specifying actual bullet source can contribute to "confusion" and/or misuse.

The next item is "working up loads". The SAAMI limit for the 357 Mag is 35,000 psi. It is near impossible for a typical end user to detect exceeding 35,000 psi with his gun and components. I know that I have run at least 45,000 psi loads through my 357 Max Contender with no sticky extraction and primers that still look ok. I have probably run up to 50,000 psi during load development.

For the specific load discussed in the OP, I did run some stuff through Quickload. Although the HS-6 charges in the Lyman data may be accurate, pushing HS-6 right up to the pressure limit is probably not the best choice to get a "top velocity". I do not trust Quickload to be accurate for charge vs pressure, but it seems to be pretty good for selecting powders based on better velocities at a given predicted pressure. For one cast 158 load I ran and for the powders I would be most willing to try, it ranked them as shown below. HS-6 was down at 19 on the list.

VV N105
Ramshot Enforcer
Alliant 2400
Accurate No.7
Shooters World Major Pistol
Hodgdon H110
Accurate 4100
Accurate No.9
Shooters World Heavy Pistol
Alliant BLUE DOT

Now for an "almost magnum" load used in higher volumes, HS-6 at around 9.0 gr would be easier to recommend.

All reloading data is a guide not a bible. Look at the test platforms used for each data point. Then without exact components & test conditions, results will be diff. Over the years I have Speer data to be at the top end.

Alot of good points! Thank you all! I have used two different 158s from Missouri Bullets, their regular lubed SWC but I also worked up the same load with their Hi Tek coated SWC. Their Hi Tek version doesn't have a lube groove, when working up the load I didn't notice a difference. I figured without the lube groove the coated version wouldn't go as deep in the case and reduce pressure but once I got over 10 grains it still seemed off. I will say that neither of the two loads seemed overpressure, at least not enough to be dangerous. I can't really pin point it exactly but something was telling me it was wise to back down some. Up to 9.8 grains was just fine, I've since backed down to 9.6-9.7
Another thing might be the fact that I haven't been hand loading for a real long time. If factory loads are running from 25-30,000 psi on average and I'm just now shooting a load that's running close to 35,000 that could be why it feels like it's too much. I had some of Remingtons 125 grain JSPs and I thought those loads may have been too hot. Those are known for being hot loads so maybe I'm just not used to shooting full on max loads in 357? 9.5 to 9.8 grains felt exactly like shooting factory 158 grain JSPs from PMC and Federal. The only difference is my hand loads don't expand the bottom of the case. The factory loads always expand the bottom of the case for some reason.
That's one of the things I can't stand about Hodgdon data is the 10 inch test barrel, they use a 7.5 test barrel for 38 special. It makes it very hard to tell what to really expect from their loads. It's not so much that I'm trying to get top velocity with HS6, it's that they list the 10.2 load as "potentially most accurate" for their 158 so I really wanted to get there safely. Perhaps I need to find a commercial caster that uses that exact mold?
All in all I'm happy with 9.6 to 9.7, I might even back it down a little further to 9.5 grains. No sense in raising pressures when 1 or 2 tenths isn't going to make a huge difference in performance.
I plan to try one of the actual magnum powders soon, most likely 2400 or Accurate #9 if I can't find 2400. I'm surprised #7 ranked higher than #9 for 158s.

Found something interesting, I looked up the mould that I was getting the data from. I was using data from the 358665 RNFP when I should have been using the data from the 155 grain 358156 SWC. While I don't have the same exact bullets from that mould I'm guessing mine are closer to the 155 profile. The 160 grain RN mould also tops out at 9.7 and both boolits are supposed to get 1271 and 1225 respectively. Looking at boolits casted from the RNFP mould they look like they'd go deeper in the case than the swc but two other boolits in the 155-160 grain range top out at 9.7 so that's probably why somethings not right when I get past 9.8 grains. The 150 grain SWC goes to 10 grains and that makes sense because a lighter boolit usually requires more powder. Maybe there's just something about the RNFP mould that requires more powder? In any case I think I'm right where I want to be in the 9.6 to 9.7 range and I should be getting the performance I was looking for. I may even rework the load and see which I get more accuracy from. Thanks for all your help and happy new year everyone!!!!