Reconciling discrepancies in reloading manuals

[Postman10mm]

I'm working on .357 158 gr LSWC MBC 18 BNH loads with HS-6 and am looking for clarification.

I have Lyman's 49th edition and Lee's current reloading manual. I also have access to manufacture's posted data and am having trouble reconciling wildly different information.

Lee republishes manufacture's data, but Lyman actually tests and develops their own loads.


Hodgdon and Lee have a min and max of 6.0-7.0 HS-6 for my bullet.

Lyman's loads for a 160 gr LSWC starts at 8.2!

That is a huge jump over Hodgdon's max or 7.0.

So who do I believe?

 

[CTSixshot]

Beats me, neighbor!
FWIW, Lyman 47 doesn't list any 357 Magnum cast bullet load data for HS-6. There's only one HS-7 load for the #358242 121g LRN (10.0g to 13.2g) and this is under the T/C Remington XP-100 section.
Also, I do know a fella that works for Lyman at the test-firing range, so he might be able to assist you.

 

[Jellybean]

You need to take a closer look at the data you referenced. Neither one is listing your bullet specifically and the 160 gr. bullet in Lyman 49 is a RN. Both manuals list pressures for their max loads and there is a lot of explanation to your question there.

The Lee manual doesn't give you any information about the type of bullet used, other than it was lead and 158gr., so even assuming it's close to what you have is a mistake, and they don't tell you what kind of test equipment or what kind of primers they used.

To answer your question directly, I never trust Lee over anyone else.
Good luck.

 

[Postman10mm]

Lyman also lists a 155 grain LSWC starting at 8.5 grains of HS-6. They note that this bullet is comparable with a 158 grain LSWC.

I'm afraid the difference in pressure is as confusing as the difference in loads.

Hodgdon's max is ~15k CUP, I don't have the book with me at the moment, but Lyman's is considerably above that.

I'm taking from your comments that this pressure difference indicates something clear to you. Could you explain what you are interpreting?

 

[Fkimble]

Some data is developed using swaged bullets. The velocity on these is kept on the low side because they tend to lead severely is pushed too much. Other data is for cast bullets, these are much harder than swaged and can be very hard depending on the alloy used. The velocity for cast can be at or near that of jacketed bullets.

 

[Postman10mm]

I understand lead, of any hardness, will have greater lubricity than a jacketed bullet, and will therefore require less powder and pressure to achieve similar velocity.

My confusion, inexperience and uncertainty come in to play when trying safely develop loads for hard cast lead bullets.

In this instance, I'm trying to determine whether I may safely use Lyman's loads for a bullet of slightly heavier weight, yet different profile.

My larger objective, is to better understand the purpose behind manufacture's reducing loads for lead bullets and using this understanding to safely develop loads for hard cast bullets.

 

[minconrevo]

Manuals have used CUP (copper units of pressure, based off a copper crusher spec) as well as PSI (more current method).

Powders have changed over time. New Unique and old Unique are not the same, for example. I have some Lyman manuals from the 1960's with loads for many powders that are significantly "hotter" than what is published today.

Occasionally there are typo's in the manuals.

Pressure generated by a bullet has to do with its weight, as well as how much of the bullet contacts the barrel sides. Pressure also has to do with the actual bullet diameter, as well as the barrel actual land and groove measurements.

Generally you can safely substitute a bullet, of the same material, diameter and sidewall contact numbers, for one of the same, but different profile. An example could be a round nose for a semi-wadcutter hollowpoint.

Hard cast bullets will lead the barrel, when driven to a velocity past their capability. Powder has some bearing on this.

 

[Jellybean]

I'm afraid the difference in pressure is as confusing as the difference in loads.

Hodgdon's max is ~15k CUP, I don't have the book with me at the moment, but Lyman's is considerably above that.

I'm taking from your comments that this pressure difference indicates something clear to you. Could you explain what you are interpreting?

Without a detailed list of the components and equipment used for both sources the comparison is more of an 'apples to oranges' than 'apples to apples' contest. The reason Lyman has a max charge of 8.5 and Lees is only 7.0 is because Lyman loaded to a higher pressure. But you don't have enough information to tell you why the testers in the Lee/Hodgdon data stopped so short. It may be leading or just because some data suppliers don't go as high with lead because they don't make lead bullets and it's not good for advertising, the possibilities are endless.

The rule of thumb, or rather the rule to keeping your thumb, for reloading is to start low and work your way up to a safe level as there are a lot of things that will affect pressure. Both manuals are only good as a general reference, and are not supposed to be written in stone absolutely what you will get.

One of the biggest reasons for leading that I've seen is poor bullet to bore or cylinder fit. I don't doubt that Lyman was able to get their lead bullets up to the high pressures listed without leading since they made them, while Lee/Hodgdon probably used commercial bullets that didn't properly fit the test firearm/barrel that they used to get the data.

 

[Forrest r]

Another difference in why there's what is perceived to be conflicting reload data is because of the bullets being used.

Lyman tests their own bullets; let's say a 158gr SWC bullet for example. The test results/load data is specific to that bullet & that bullet only.

A Hogdgon or Alliant reloaders guide will list data on a 158gr SWC bullet also. But they don't know what the brand of the bullet your using is so they stay on the side of caution. They end up giving you generic load data that they know that will be safe that they acquired from a blend of different test bullet/powder combos. Their data might be 2 grains of powder less than Lyman's data, but they know it will safely work on any 158gr SWC bullet including Lyman's bullet.

 

[Paul5388]

The last cast bullet Speer offered in .357" was seen in Speer #8 BBHFarm Gallery :: Speer 8, 2nd Edition, 1971 :: aag. Speer #9 used a swaged bullet and the loads reflect that downward change, by restricting velocity to about 1000 fps. SR 4756, HS-6 and AL-7 were about optimum for producing higher velocities (even higher than 2400).

 

[amazingflapjack]

Lead

Lee offers a general-oveview caution- on their literature "never select a load intended for a bullet lighter than you are using. Loads for a slightly heavier bullets are safe"

And then from Reloading Pages of M.D. Smith "f you want to use lead, pick one of the jacketed bullets (of similar weight and powder type) and deduct .5 - .8 grains for a guide.

Also-laser cast bullets will mail or fax load info for their hard cast bullets, which I like.

I have been wrestling with some of the same stuff recently myself. Didn't have much of a problem until I got a 610-2, it seems the lead bullet data for "auto rounds" is kind of slim. If you have a good recipe for the above, I would appreciate it! Flapjack

 

[Rule3]

FWIW, I load the same bullet but do not use HS-6. It is a hard bullet, not quite Linotype but hard none the less. The closest powder to HS6 that I have loaded them with is Blue Dot, then 2400.

For target/plinking I get the same bullet in a BHN of 12.

I use the data from Lyman 49th and 4th addition Cast bullet.

The load data from Hodgdon is most probably for a swagged bullet and Lees data is just reproduced from the powder companies data.

I have used most of the other powders listed and load just short of max loads. If you use the Hodgdon data, they will be safe, mild target loads, not really full Magnum loads IMO.

The only way to be sure is start low and chronograph your loads.

For hard cast lead bullet data I think Lyman is the best source.

 

[Postman10mm]

OCD1,

Which bullet, referenced in Lyman, are you using for a starting point for the Hard MBC 158s?

 

[Rule3]

OCD1,

Which bullet, referenced in Lyman, are you using for a starting point for the Hard MBC 158s?

In Lyman #49 I use the data for the 160 gr RN #358311
there is also the 155 gr #358156.

In Lyman Cast Bullet 4th. There is data for a 158 gr # 358665
I will send you the HS-6 data (do not want a copyright cop after me)

The bullet weights are all so close and I seat to the cannelure so there is not much difference. All the loads min and max are very close. I usually just play it safe and go in the middle somewhere.

 

[Rule3]

The PM I just sent you is in regard to this thread. I see you have another similar one going with different powder so it's getting confusing.

 

[mkk41]

Different molds/bullet design(surface area=friction) , load density(longer bullet=compressed load)), different lead alloy/hardness , different testing equipment/methods/climate/conditions , different powder lots , publishers safety guidelines , legal liability concerns , etc.

Generally , the faster the powder , the more variation.

 

[johngalt]

My opinion is probably a little different than a lot of others.

My first choice is the bullet manufacturers, specifically Speer and Hornady. They test their loads in real guns, and I have more confidence that their loads reflect reality.

Alliant now uses Speer data, so they are an ok source also.

IMHO, Hogden is a very poor source, to be used only if I can't find any data some other place. Their loads are very anemic, with wildly optimistic velocity numbers that you will NOT reach in a real gun. Yes, their loads are safe - you won't blow anything up, but I don't like inaccurate data.

Lee does not independently test their data, it is basically a compilation of the powder manufacturer's data. About the only time I use it is if I need a load for a bullet/powder combination that I can't find in my Speer or Hornady manual. It was my first manual starting out, but I've since found there is better data out there.

 

[Jellybean]

John, you're not that alone in your thinking. Hodgdon does supposedly use a test barrel and receiver to get their pressures but their velocities are attained with firearms with barrels longer than SAAMI standards to make it look like their powders are giving you better results, as in a marketing ploy. I hardly ever use their data either because it doesn't give a fair comparison of how their powders rate against others data, and this is a reason I do like the Lyman manuals. All their data for a given bullet comes from the same firearm, even if it is a test receiver. Lees' manual might list 20 loads, say for example .38 spl. 158 gr. lead, but they don't tell you that every load listed was from a different firearm using a different bullet.