conflicting data from Hogdons website ?

I just started reloading a few months ago so forgive my ignorance if thats all this is, but this really seems to be a conflict here.
I was looking at Hogdons website, at their reloading data and this really struck me as having something seriously wrong.

Both are 125 GR. CAST LRNFP using Universal powder.

Quote:

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357 magnum
125 GR. CAST LRNFP Hodgdon Universal / .358" / 1.580" / 4.8gr 1046fps / 11,000 CUP ---- 6.8gr / 1401fps / 34,200 CUP

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versus

Quote:

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38 Special
125 GR. CAST LRNFP Hodgdon Universal / .358" / 1.445" / 4.3gr / 872fps / 8,700 CUP----4.7gr / 1036fps / 16,800 CUP

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Now, how can, using the same bullet, the 4.8 gr of Universal be 11000 cup on the 357 chart....but on the 38 special chart 4.7gr, .1 gr less, be 16,800 CUP ????

I realize that some powders are funny that way, but the 38 special data uses (4.3gr / 872fps / 8,700 CUP) as its starting load, so apparently 4.7 shouldnt be that far off the chart.

Are these charts just wrong or is this really that complex ?

The first thing I noticed is that you specified Unique in your text, but that data is for Universal...I'm sure that is a typo. Take a look at the OAL for both loads. The shorter OAL for the 38 special will create an increase in pressure as the bullet is seated deeper.

Quote:

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Originally Posted by The Keymaster

The first thing I noticed is that you specified Unique in your text, but that data is for Universal...I'm sure that is a typo. Take a look at the OAL for both loads. The shorter OAL for the 38 special will create an increase in pressure as the bullet is seated deeper.

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My bad....universal...I have unique on the brain :)
It was Hogdons powders I was looking at. :)

Quote:

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Originally Posted by The Keymaster

the shorter OAL for the 38 special will create an increase in pressure as the bullet is seated deeper.

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WOW.
I understood that the shorter casing would cause a higher pressure, but nothing Id read so far made me think it would be THAT much higher with Universal.
Guess I better keep reading :mrgreen:

You did right. When you don't understand something, STOP and ask. And it's a very good question. Yes, the reduction in case volume ups the pressure level significantly. It's a good reason to pay attention to recommended OAL - seating a bullet too deeply does the same thing. It's not just Universal, it happens with every powder.

Now think about this: What happens in a high pressure semi auto pistol case like .40S&W when the bullet telescopes during feeding? Same thing again, and the consequences can be deadly. If you are redlining your loads when this happens, KABOOM!!!!

When you get a chance, you really ought to invest in several current manuals. The next time you spot what appears to be an anomaly, you can look up the same load in the other sources and see if a majority of them agree. (That doesn't mean we don't want you asking questions here!!! You are not the only one who learns from them. For every newby that posts a question like that, there are many who are not as comfortable asking but really need to know.)

Thanks for all the help guys :)
Im definitely glad I decided to go with the 357 at this rate. Seems to be much less chance of blowing myself up :D
Seems like a 357 can handle over 40,000 CUP, which I certainly dont ever intend to go into the 30's, let alone push even close to the maximum loads.

I shot about 30 rounds of these Hornady XTP's that I loaded with 7 grains of Unique in the 38 special casing using CCI magnum primers.
They seemed 'stout' but didnt jam my wrist or anything...probably a stern +p or +p+ or so. Definitely manageable with no signs of pressure problems (casings seemed fine, no primer anomalies).

So at this point we have two recipes we use.

Range ammo - 4 gr Unique with 158 gr cast LRN (pure lead so keepin it slow) in either the 38 spec or 357 mag casings

Defense ammo - 7 gr Unique with 125 gr Hornady FP/XTP in the 38 spec casings (just what I have more of)

They both shoot great, but does anyone have any input on either ?
:)

You are unlikely to see pressure signs on the primers of handgun rounds. The warning sign is difficult extraction from a cylinder that normally has no problems. The cast load is not hot and will do fine. The 125gr load in .38spec is a MAX load in the +P range, START at 5gr and work up to it. The same bullet in a .357 case goes 7.6-9.3MAX with UNQ in my Sierra Manual. If you are wanting a self defense load and the revolver is chambered for .357, I would go with the larger case, work up from START, and use the most accurate load (not necessarily the hottest).

ain't nobody or nothin gonna know the diff of 50-100 fps [except the bullet].
sometimes a slower powder will do what you want with less pressure,and will feel like less recoil too.
unique is a fine powder and very versatile but i like to step to a bit slower powder when i want to ratchet up the velocity and keep the pressures down some, especially with cast or defence loads.
alliant 2400 comes to mind as does aa 1680.