38+P Load Data Question.


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357mag357
November 9, 2008, 09:23 AM
Speer Manual #13 has a listing for a 38 Special+P 125 grain bullet using 7.8-8.1g of AA#5. I double-checked with Accurate Arms website. They have a listing of 6.4-7.1g for the same 38 Special +P 125gain bullet. This seems like an extreme difference for the same load. I did load a few using 7.8g and with 8.1g with no pressure problems that I could see. I donít have a chronograph to see how fast they are going either. What are your thoughts on the listings?

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Bozo
November 9, 2008, 09:59 AM
If you look in the Hornady manual you will see that it lists that combination at 7.6 grains. Some are more conservative than others, it also has to do with the way the load is tested, that is which pistol or pressure barrel. Just because it is a 125 grain jacketed bullet does not mean there is not differences between manufacturers.

The Bushmaster
November 9, 2008, 10:13 AM
Some bullet manufacturers are aware that AA #5 is very temperature sensitive too.

loneviking
November 9, 2008, 10:31 AM
Here's where the saying of 'load 'em until you have to beat the cases out with a stick or the primer pockets deform' comes in. If your gun is fine with the load, carry on! Some of the old reloading manuals from the late 70's/early 80's had some very hot loads by today's standards.

Robbie
November 9, 2008, 10:33 AM
Another thing you have to consider is if the extra load will even be useful. More powder only means more power to a certain point, to much powder cannot fully discharge before the round exits the barrel. The powder will ignite as soon as the round exits the barrel, the result is a louder bang and bigger flash anyone whos been in the military knows this is bad. You also have more residue to clean up. I would find a good ratio that fits your weapon if its short barreled watch the grain size of the slug, if its too heavy the bullet cannot accelerate to its intended exit speed and when it leaves the barrel the unburnt powder will push on it with no support and this kills accuracy. Id rather land a weaker blow center mass than miss all together. Most ammo is tested with a 4-4.5 inch barrel so unless you clock your bullets going down range its hard to really know how fast its going and if the extra load is worth it.

jfh
November 9, 2008, 11:29 AM
for sorting out this recipe:

Current published data includes-

1. AA 3.2.2 and AA2004: 6.8 gr. This is based on standard 38 Special psi criteria--3.2.2 lists this at 16,300 under a 125 XTP

2. Speer 14: 7.1 gr. for any Speer 125 jacketed. Pressure criteria--"under 17,000"

3. Speer 14: 7.8 gr. for any Speer 125 jacketed. Pressure "under 20,000."

Current SAAMI specs call standard 38 Special to be 17,000 and 38+P to be 20,000. (See RMc's comments in post 9--3 down.) Preceding standards ran "standard" to 18,500 and "plus-P" to 20,500 (IIRC).

4. Then there is the (European / Metric) CIP standard: CIP does not differentiate for 38 Special--its one standard is (the equivalent of) <=21,750.

One "rule of thumb" given to me by a (powder) manufacturer ballistican is to take standard load recipes and add 5% charge weight for Plus-P and to add 9% charge weight for CIP.

Note that using the Speer 14 standard 38 Special recipe for 125 jacketed bullets--7.1 gr--and adding 9% gives 7.8 gr.

All of these calculations are based on a typical LOA, or BSD / Bullet Seating Depth. Currently, I am testing for the effect of Long and Short LOAs at near-max pressures. Short LOA tests use the bullet seated to the absolute maximum depth but still within the cannelure . Needless to say, BSD varies depending on the bullet design--and maximum depth seating will spike pressures.

For this particular topic, it would appear that 7.8 gr. is probably the upper limit of max pressures for the 38 special--but that LOA / BSD might justify the 8.1 charge. Depending on the revolver, you may or may not want to shoot it routinely.

FWIW, I find that #5 is an extremely useful 38 Special powder--you can load it mild to wild, so to speak, and it performs consistently. Lower charges / pressures tend to be dirtier, and overall I consider the powder to be dirtier than (for example) Ramshot True Blue, and it usually doesn't produce real low SDs except at near-max or max pressures--but it does work well overall.

Jim H.

rcmodel
November 9, 2008, 01:24 PM
with no pressure problems that I could see.That's good!

Because if you can see any pressure signs, with any .38 Special load, you are already well off the charts pressure-wise!

243winxb
November 9, 2008, 02:59 PM
Different brass and primers can make a big difference in 38 spec. using the same bullet.

RMc
November 9, 2008, 03:43 PM
Gentlemen:

The SAAMI standard for the .38 Spl. +P was raised to 20,000 psi sometime in late 1994!

SAAMI changed the .38Spl. +P standard from 18,500 psi to 20,000 psi when ammunition manufacturers could not provide the performance levels demanded by consumers.

The current SAAMI MAP pressure for the .38 Spl. +P is 20,000 psi or 20,000 cup. That while the two systems often give different values in this case they read the same.

The Speer #13 manual lists loads for the 158 LSWCHP with velocities up to 1037 fps in the +P 38 section with Alliant Power Pistol under the 20,000 psi standard.

Looks like there is life in the old .38 Spl yet --- with current pressure tested data no less.

The Bushmaster
November 9, 2008, 03:59 PM
Never knew that ol' gal ever died in the first place...:D

Steve C
November 9, 2008, 05:42 PM
Data from Speer should be fine. I've used 6.0grs of Unique with 125gr JHP's for years, also listed in Speers #13 at a velocity of 1,082 fps from a 6" K38 and have chrono'd this load at 1,053 fps velocity from my 4" S&W M67. I'd expect the same from their AA#5 load.

357mag357
November 9, 2008, 06:00 PM
Thank you all for the info. I am using a GP100 with a six inch barrel. Will have to get a chronograph for Christmas.

jfh
November 9, 2008, 07:59 PM
RMc: Can you provide a link to an Official SAAMI list--e.g., one from their site?

I double-checked my links for SAAMI pressure lists--and found only one listing the 20,000 PSI limit for 38+P--and that was at handloads.com, with no attribution.

Ramshot, for example, still uses 18,500--you can see their list here (http://www.ramshot.com/powders/). Clink on the link for SAAMI on the left side--

I had thought it was that SAAMI had set its 38+P spec to 20,000 (down) about 1994--but about 2003-2004, lowered it to 18,500.

It is hard to imagine that one cannot find a simple PDF for this list on the official SAAMI site without having to pay for it....

Jim H.

RMc
November 9, 2008, 10:54 PM
The current SAAMI ANSI/SAAMI Performance Standards book for handguns was published in 1993. The change to the .38spl +P standard was made in late 1994.

An involved discussion of this can be found at:

http://shootersforum.com/showthread.htm?t=11047

From this you can see that a number of phone calls were made and email messages sent to run down this information in 2004.

The current contact point for SAAMI is:

Rick Patterson
203-426-1320
rpatterson@nssf.org

jfh
November 10, 2008, 12:40 AM
RMc: Thank you very much for that link.

It provides missing documentation and information about the SAAMI standards.

Any of us working with 38 Special at near max pressures now have a better basis for reading the entrails found in the current published data.

Does anyone have any links to "metallurgical" discussions--i.e., about the nature of the alloys used in 38 Special frames?

Jim H.

fecmech
November 10, 2008, 12:35 PM
I have no links to "metallurgical" data but have a reference to a study done by the HP White lab ( Pressure Overload Tests) for the Treasury Dept done in 1971. "Catastrophic" failures ie. fractured cylinders split lengthwise along the walls of of the top chambers, with the top strap severed at it's juncture with the rear of the frame and bent upward at an angle of 20 to 30 deg.
These tests showed that approx 70,000 cup or more was required to show catastrophic failure on high quality medium frame .38 spl revolvers. Approx 50,000 cup for the same damage on light frame U.S. manufactured revolvers and less expensive imported guns.
This info was in a Dec 1978 article in the American Rifleman magazine regarding supposed detonation of Bullseye powder in target loads.
I have never worried much about + P loads in 38 specials since reading this.

Larry E
November 11, 2008, 08:30 PM
This is a good example of where a chronograph would be handy. If you know what sort of performance you're looking for you don't have to guess with a chronograph. A $100 chronograph is cheaper than a blown up gun or Dr's bill either one.... :eek:

Speer used to list some 9x19 loads that'd make a liability lawyer's eyes light up with glee they were so hot. I wouldn't have known except that I chronographed some of them from the Hi Power I had. The velocity was lower with the highest charges than with lighter charges - a sign that things have gotten out of hand pressure wise.

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