2 different data loads from 2 different books

6.9gr of Bullseye in a .357 mag with a 158gr LSWC?? Hmm, that doesn't sound right. That's about the right weight for Unique which is much slower burning. I'm skeptical of that data, though I have no experience with bullseye.

ETA: Here's what Alliant has
http://www.alliantpowder.com/reloaders/powderlist.aspx?type=1&powderid=1&cartridge=28

The difference is likely because they are different 'types' of lead bullets.

Swaged lead bullets are 'soft' lead alloy and their speed is kept within a maximum to avoid leading.

Cast bullets are 'hard' lead alloy and they can be driven much faster without leading.

usmc0811 said:

I have a 158gr LSWC cast bullet I am trying to load up using Bullseye for use in my .357mag. I looked at a few of my reloading manuals for a recipe and see some big differences between these two books.

Modern Reloading 2nd edition manual it says:
Start 4.2 Max 4.8 For a Lead bullet COL 1.570"

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Where did you find this? Is this from the Lee manual? My Lee modern reloading 2nd edition has a very different 357 data for Bullseye and 158 lead bullet. Your data looks more like what is in the Speer manual.
https://reloading-data.speer-ammo.c...8_caliber_357-358_dia/357_Magnum_158_LSWC.pdf

You list the sources, but what is the date? Expect old data to have higher maximums. New data is gathered differently, and powder has been improved. Lawyers input be damned, stay with published data.

Current data from the powder mfgr is the correct way to go. Exceeding mfgr recommendations is a good way to become a future organ donor.

The OP's Lyman data is consistent with their 50th Edition, circa 2016.

I checked the Lyman 50th Edition and the 4th Edition of the Cast Handbook. Lyman has quite a few sets of data for .357 mag with lead bullets where they list Bullseye as one of the powders, but don't list Unique in the same chart. Makes me wonder if that was a mistake.

Bullseye seems like a very poor choice for .357 mag to me. But I don't know much about it. So perhaps it give particularly good accuracy?

Just a couple thoughts; for reloading a lead SWC, seat the bullet to the crimp groove and disregard the book OAL. I have safely loaded many thousands of rounds of revolver ammo like this, no problems. I have a Lee manual, but it's the last one I look at for load data. The front half is an entertaining and informative read, but I have found the load data sketchy and lacking. An excellent manual for starting a reloading library is the Lyman 50th, good front half "how to" info, and lots of jacketed and cast bullet data. Reloading manuals are not hard and fast formula, but reports of what a testing lab found when they used the listed components and dimensions. They often use different equipment, like some used actual guns and some use universal receivers with different length barrels. So, different results in different manuals.

I consult at least two manuals or powder maker websites when looking for load info on a new powder. Sometimes they’re as different as you see there, so I’ll be conservative when I start out.

It seems to me that a lot of Lee info is geared for their dipper system of measuring, which isn’t as precise case-to-case as a dropped charge from a powder measure IMHO. That may be why it’s so low compared to the other info, I don’t know for sure.

I agree with Wronghanded that 6.9 Unique sounds close to max... I’ve done 5.5 gr Bullseye with a 158 gr SWC in a .357. That’s not max, but it’s a good load and about as high as I’ll go with that powder/bullet/cartridge combo.

Stay safe.

mdi said:

Just a couple thoughts; for reloading a lead SWC, seat the bullet to the crimp groove and disregard the book OAL..

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While it may be the standard procedure for seating and crimping bullets with a crimp grove, one cannot really disregard the book OAL when it comes to powder charge. Different bullets have different amounts of bullet seated inside the case because of where the crimp grove is. More bullet in the case, less case capacity. This could be one reason for the difference in powder charges in the OP. The shorter OAL recipe is also the lower for powder charge. Same for profile and bearing surface. All of these are legitimate reasons for different powder charges and why when we use a different bullet than the recipe, we need to be careful how we work up our loads.Some books are known for loads hotter than others. Lyman likes their .357 loads hot.

buck460XVR said:

While it may be the standard procedure for seating and crimping bullets with a crimp grove, one cannot really disregard the book OAL when it comes to powder charge. Different bullets have different amounts of bullet seated inside the case because of where the crimp grove is. More bullet in the case, less case capacity. This could be one reason for the difference in powder charges in the OP. The shorter OAL recipe is also the lower for powder charge.

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Nope. 0.005" difference in OAL is within the range of normal error from one round to another, and it is meaningless in this situation. The reason for the big differences in charge weight is because the low charge data is for a swaged bullet. From post #4, Swaged lead bullets are 'soft' lead alloy and their speed is kept within a maximum to avoid leading.

http://alliantpowder.com/resources/catalog/AP392_2020_AlliantPowderCatalog_SinglePages.pdf
https://reloading-data.speer-ammo.c...8_caliber_357-358_dia/357_Magnum_158_LSWC.pdf

Lyman's data is for cast bullets. From post #4, Cast bullets are 'hard' lead alloy and they can be driven much faster without leading.

That's all. There's no reason for people to be making up crazy explanations.

usmc0811 said:

I have a 158gr LSWC cast bullet I am trying to load up using Bullseye for use in my .357mag. I looked at a few of my reloading manuals for a recipe and see some big differences between these two books.

Modern Reloading 2nd edition manual it says:
Start 4.2 Max 4.8 For a Lead bullet COL 1.570"


Lyman Cast Bullet Handbook it says
Start 6.2 Max. 6.9 For Linotype COL 1.575"

I could see a little different but this seems like a lot. The Lyman start is 1.4gr. over the Modern Reloading manual start.

Any advice??

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Where are you looking? Both Lee 1st and 2nd show very close to the same data for 158gn lead and Bullseye. 5.8gn - 6.5gn BE @1.580". Also, BE and the 158SWC work much better in 38 Special.

buck460XVR said:

While it may be the standard procedure for seating and crimping bullets with a crimp grove, one cannot really disregard the book OAL when it comes to powder charge. Different bullets have different amounts of bullet seated inside the case because of where the crimp grove is. More bullet in the case, less case capacity. This could be one reason for the difference in powder charges in the OP. The shorter OAL recipe is also the lower for powder charge. Same for profile and bearing surface. All of these are legitimate reasons for different powder charges and why when we use a different bullet than the recipe, we need to be careful how we work up our loads.Some books are known for loads hotter than others. Lyman likes their .357 loads hot.

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Understandable. But I have seen many, many new reloaders post questions concerning "I used the crimp groove and the OAL doesn't match the manual". When I first thought about OAL/crimping for revolvers I thought the bullet designers/manufacturers located the crimp groove/cannalure in the proper place, taking into consideration case capacity and bullet intrusion vs pressures. So, I just used the crimp groove/cannalure as a determination of bullet seating. In over 40 years of reloading for revolvers, I have had no safety issues, no pressure issues. So, as I mentioned earlier, reloading manuals are reports of lab tests using the components and dimensions listed. Since variations in components, especially cast bullets are common, exactly matching manual dimensions is not guaranteed. Another variation to add is amount, pressure of crimp with a specific case wall thickness and a specific bullet diameter, which can make a difference in pressures. Also I don't believe reloading manual data is "Lawyered down", or purposely hotter or milder than actual results.

Lyman 50 .357 155gr SWC Bullseye Start 4.8 828fps MAX 7.0 1122 fps (higher than Alliant)

Alliant 05 .357 158gr LSWC Bullseye MAX 6.5gr

usmc0811 said:

I have a 158gr LSWC cast bullet I am trying to load up using Bullseye for use in my .357mag.
Lyman Cast Bullet Handbook it says
Start 6.2 Max. 6.9 For Linotype COL 1.575"

Any advice??

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Which handbook edition? My Lyman Cast Bullet Handbook ( third edition, circa 1980) has no such data.
Care to post a photo of the load you're referencing?

fxvr5 said:

Lyman's data is for cast bullets. From post #4, Cast bullets are 'hard' lead alloy and they can be driven much faster without leading.

That's all. There's no reason for people to be making up crazy explanations.

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Like that'll stop 'em.

One of the misconceptions about cast bullets is "harder is better and you can drive them faster". Fit is the single most important factor in shooting cast bullets. A BHN 18-20 bullet will lead barrels if it doesn't fit the barrel. I cast bullets wit mostly 11-12 BHN alloy and none harder than Lyman #2, 15 BHN. I use the #2 for my 30m cal rifles with velocities over 2,000 fps and my 44 Magnum loads running upwards of 1,300 fps. with my "normal bullet alloy". No excess leading (and I'm not the only caster to get these results). The major reason swaged bullets lead at higher velocities is because they are too soft to grip the rifling, called "skidding"...

mdi said:

One of the misconceptions about cast bullets is "harder is better and you can drive them faster". Fit is the single most important factor in shooting cast bullets. A BHN 18-20 bullet will lead barrels if it doesn't fit the barrel. I cast bullets wit mostly 11-12 BHN alloy and none harder than Lyman #2, 15 BHN. I use the #2 for my 30m cal rifles with velocities over 2,000 fps and my 44 Magnum loads running upwards of 1,300 fps. with my "normal bullet alloy". No excess leading (and I'm not the only caster to get these results). The major reason swaged bullets lead at higher velocities is because they are too soft to grip the rifling, called "skidding"...

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Even worse results can be had with micro grove barrels. I'm not saying you cant use lead but I dont buy them because I'm not trying again.

mdi said:

One of the misconceptions about cast bullets is "harder is better and you can drive them faster". Fit is the single most important factor in shooting cast bullets. A BHN 18-20 bullet will lead barrels if it doesn't fit the barrel. I cast bullets wit mostly 11-12 BHN alloy and none harder than Lyman #2, 15 BHN. I use the #2 for my 30m cal rifles with velocities over 2,000 fps and my 44 Magnum loads running upwards of 1,300 fps. with my "normal bullet alloy". No excess leading (and I'm not the only caster to get these results). The major reason swaged bullets lead at higher velocities is because they are too soft to grip the rifling, called "skidding"...

Click to expand...

I agree with almost all of that, and do most of my casting with 1-16 tin/lead, for a BHN of no more than 11. This alloy works well for me up to 1200 fps or so, if perfectly fitted. Beyond that velocity I turn to gaschecks, for peace of mind if nothing else.

But the swaged bullets are five or six BHN, and unless a fellow has the equipment to swage them to his own specification, he is at the mercy of the manufacturer. Trying to drive those very fast is a fool's errand, and I certainly understand why the loading manuals are conservative with them.

That's why you consult more than one manual, harmonize the components you are using (you are considering more than just the caliber and bullet weight aren't you?) and then start at a concensus of the Minimum Starting Load (it is called a Starting Load for a reason) and then work your loads up from there.