Did Bullseye powder change?

[a__l__a__n]

I have a copy of the 1998 Alliant load data which shows, for 158 gr SWC in 38 special +P, 3.8 gr Bullseye gives 945 fps and 17,200 psi (5.6" barrel)

The current Alliant site shows 3.9 gr Bullseye with 158 gr SWC giving 874 fps (6" barrel). (no pressure given) That's a bigger charge, and a longer barel, and 71 fps slower -- reported by the same source.

Ok, maybe that's due to variation in test conditions -- temperature, wind, phase of the moon.... But it gets worse. The current Alliant site shows 4.8 gr Bullseye in .357 magnum with 158 gr SWC giving 939 fps in a 6" barrel. That's a full grain more powder than the 3.8 reported in the 1998 data, with a longer barrel, giving a slightly lower velocity -- all as reported by Alliant.

Did Alliant change the powder? Or is something else going on here?

 

[Chuckdog]

The powder hasn't changed. No two batches may be identical though.

Every barrel's different? Every bullet's different? The published data is usually averaged data.

Much data has been updated in recent years due to improved methods for measuring peak pressures.

Handgun cartridges are funny. A friend and I cut a 10.5" Ruger .44 mag barrel at .5" intervals. Using the same load, we actually measured higher velocities with shorter barrel lengths.

I don't have the figures now, but I remember @ 5"'s getting higher velocities than we were getting with anything we tried below 8"'s.

We were quite surprised? A chronograph is very handy.

I used to load .44 mag and .45 Colt to ridiculous levels. I'd pack W296 in till bullet seating was a real challenge. Folks accused me of using a cheater bar on my press. I found out that after a certain point, more powder didn't produce any more velocity, just muzzle flash, blast and recoil, but nothing good.

 

[Clarke123]

Likely it's that the testing method has "evolved".
Many manufacturers are now using a "vented test barrel" for revolver-type loads:
Scroll down this page for a complete discription:


http://www.frfrogspad.com/miscellq.htm#duplicate

 

[a__l__a__n]

Today's charts generally show lesser results for a given charge, and often show lower maximum charges. But "back in the day," people loaded ammunition using those older charts. It seems that if the velocity numbers were unrealistically high, that would have become general knowledge (but apparently it didn't).

If modern guns have a lower margin of safety for pressure (or if the lawyers have insisted on a higher margin of safety) then I can understand why the maximum charges shown in the charts are lower today. But it doesn't explain why a given charge today results in a slower bullet than it used to.

 

[a__l__a__n]

I sent the questions to Alliant and received their response:

I have a copy of the 1998 Alliant load data which shows, for 158 gr SWC
in 38 special +P, 3.8 gr Bullseye gives 945 fps and 17,200 psi (5.6"
barrel)

**Those velocities were out of unvented test barrels, so they are higher
than from a typical revolver which vents gas out of the barrel/cylinder
gap.

**The pressure spec for 38 Special +P is now 20,000 psi, so the above
load is not actually +P.

The current Alliant site shows 3.9 gr Bullseye with 158 gr SWC giving
874 fps (6" barrel). (no pressure given) That's a bigger charge, and a
longer barel, and 71 fps slower -- reported by the same source.

**This velocity was measured out of an actual revolver. These loads
were developed by Speer, one of our sister companies.

Ok, maybe that's due to variation in test conditions -- temperature,
wind, phase of the moon.... But it gets worse. The current Alliant site
shows 4.8 gr Bullseye in .357 magnum with 158 gr SWC giving 939 fps in a
6" barrel. That's a full grain more powder than the 3.8 reported in the
1998 data, with a longer barrel, giving a slightly lower velocity -- all
as reported by Alliant.

Did Alliant change the powder? Or is something else going on here?

**Bullseye is still the same. In our 38 Special section, we still list
a 3.5 gr charge with a 158 gr lead bullet. If this load works for you,
I see no reason not to continue with it.

 

[Chuckdog]

You want a real shock? Get some 40 year old manuals and compare the data.

There are faster barrels, identically manufactured, but vastly different performance.

There are so many variables to affect the numbers that I let other folks worry about making sense of it. It's kinda like gas mileage estimates on cars, some will make the numbers, some don't.

I'm just not one to think I know more than the manufactures do. Don't get me wrong, I know misprints occur. I check and compare the data using more than one source. I've pushed the envelope more than I like to admit, God looks after drunks and fools!

I recommend using the most up to date manuals, but I still have and use my old ones.

A chronograph is an asset, a great addition to any loaders arsenal.

 

[a__l__a__n]

You want a real shock? Get some 40 year old manuals and compare the data.

There are faster barrels, identically manufactured, but vastly different performance.

There are so many variables to affect the numbers that I let other folks worry about making sense of it. It's kinda like gas mileage estimates on cars, some will make the numbers, some don't.

I'm just not one to think I know more than the manufactures do. Don't get me wrong, I know misprints occur. I check and compare the data using more than one source. I've pushed the envelope more than I like to admit, God looks after drunks and fools!

I recommend using the most up to date manuals, but I still have and use my old ones.

A chronograph is an asset, a great addition to any loaders arsenal.

Is there a range around here (I'm in Gwinnett) where I can set up and use a chronograph? Even better, where I can rent time on one?

 

[oldpapps]

a_l_a_n,
You got me to wondering... I haven't loaded 38s since about 1980 or so. But...
I dug out some old books and this is what I found.


from 1974


from 1987


newer, 2010

The Richard Lee book doesn't list the test weapon. Sorry I don't know how to expand my scans on the page.

I listed the book info in red on each scanned paged.
The numbers don't lie or match well.
My answer is get a .45 and a coron. Of course the loading data for the .45 AUTO will vary too. But then you can do it the way I do, 5.6 grains of 231 for all slugs in a .45, I seldom use anything other than 200 grain swc.

Enjoy and be safe,

OSOK

 

[a__l__a__n]

Someone should start an online database of chronograph reports that captures all the relevant data, including gun model and barrel length. Handloads.com does part of that but most people don't supply even the barrel length which obviously is an important piece of data. Just entering the powder amount and saying "I like this load" is pretty useless.

I've surveyed the info google returned to me for Bullseye under lead SWC / RN and captured it in a google documents spreadsheet here. It's sorted by barrel length, powder weight and velocity. I've kept the links to where the data came from so people can verify the data. Of course it's just as reliable as anything else you see on an internet forum, which means don't trust it without verifying everything yourself! Maybe it will be interesting to someone...

 

[a__l__a__n]

a_l_a_n,
You got me to wondering... I haven't loaded 38s since about 1980 or so. But...
I dug out some old books and this is what I found.

View attachment 69617
from 1974

View attachment 69618
from 1987

View attachment 69619
newer, 2010

The Richard Lee book doesn't list the test weapon. Sorry I don't know how to expand my scans on the page.

I listed the book info in red on each scanned paged.
The numbers don't lie or match well.
My answer is get a .45 and a coron. Of course the loading data for the .45 AUTO will vary too. But then you can do it the way I do, 5.6 grains of 231 for all slugs in a .45, I seldom use anything other than 200 grain swc.

Enjoy and be safe,

OSOK

Interesting. Those older manuals tend to contradict what the Alliant guy told me. They tell you what revolver they used (a real gun, not a test barrel) and they got substantially higher velocities than the newer manuals show.