Accurate data for Accurate (AA) powders

[baz]

I'm still learning the ropes, working up some 357 loads with AA #7. For my initial loads, I used the Accurate Powders guide 3.2 PDF from their website. For AA #7, with 125 grain Hornady XTP, it showed:

Starting Load: 11.9 gr, 1374 fps
Max Load: 13.2 gr, 1562 fps
Primer: WSPM
Barrel length: 6"

This guide doesn't list the barrel length, but the load data is the same as in the 3.1 edition, which indicates a barrel length of 6".

Since this load is to be used for a 2# snubbie, and as an alternative to the commercial 38 spl +P I've been shooting in the gun, I'm aiming for something of a "lite" 357 load that will be a) more powerful than commercial 38 spl +P loads, but b) not as jarring as shooting commercial 357 magnum loads in the gun. I started at 11.9 grains. That went well, so I moved up to 12.2 grains. That worked well, too, and I have no plans to go higher, at least for this gun.

But I'm curious why other published data is so different. I have the "loadbook" for 357 magnum. In the Hornady Bullets section, for the 125 grain XTP, and AA #7, it shows

Starting load: 10.5 grain, 1250 fps
Max load: 11.5 grain, 1400 fps
Primer: WSPM
Barrel length: 8"

If I went by the Hornady data, at 12.2 grains I am well above the maximum load!

The data from the section for Sierra bullets:

Starting load: 12.5 grain, 1250 fps
Max load: 13.7 grain, 1350 fps
Primer: CCI 550
Barrel length: 6"

If I went by the Speer data -- and I know the bullets are different, but they are not that different, I don't think -- I'm not even at a starting load. And for what its worth, the bullets that I'm actually using are either Winchester XTP or Speer GDHP's. Speaking of which, the load data for Speer GDHP's from the loadbook:

Starting load: 12.0 grain, 1045 fps
Max load: 13.5 grain, 1134 fps
Primer: CCI 500
Barrel length: 6"

My load fits in here at the lower end. These loads are closer to the Accurate powder guides, but the fps are inexplicably quite a bit lower, especially considering both report using the same barrel length (6"). Besides the bullet -- Hornady XTP vs. Speer GDHP -- what could account for such a variation in chronographed fps? Do note that the Accurate powder data reports using a magnum primer with AA #7, while the Speer data uses a standard small pistol primer. Can the difference in primer explain the difference in fps?

Finally, when I turn to the powders section of the loadbook, where they have data for Accurate powders, it is somewhat different than what is published in the guides I got from Accurate's website:

Starting load: 11.9 gr, 1527 fps
Max load: 13.2 gr, 1735 fps
Primer: CCI 500
Barrel: 8"

The start and max loads are the same, but the fps is greater by about 150-200 fps. I suppose that makes sense given 2" more of barrel length? And here I note that the primer is CCI 500, a standard small pistol primer, not the magnum pistol primer used in the current Accurate Powders guides. I'm presuming the data from the loadbook is from an earlier Accurate Powders guide.

I know, I know, there are lots a variables to explain these kinds of variations in load data. But that Hornady data is really out in left field, and is hard to explain rationally. When one source gives data that starts well above where another source maxes out, you gotta wonder about one or the other.

In the end, I think I have a load that works for me: 12.2 gr of AA #7, with standard small pistol primers (I've used both WSP and CCI 500 in testing these loads), with either Winchester XTP or Speer GDHP 125 grain bullets.

Now to develop some loads for a 6" Tracker in 357.

 

[joneb]

My Hornady data lists , Federal 200 primers and 11.6gr of AA#7 to start with a 125gr HP/XTP, and 13.0gr is the MAX load, Use with Caution !

 

[baz]

My Hornady data lists , Federal 200 primers and 11.6gr of AA#7 to start with a 125gr HP/XTP, and 13.0gr is the MAX load, Use with Caution !

I think I'm about to learn a valuable lesson. Where did you get your data?

 

[D R Greysun]

Accurate must have revised their load data. My '2003 Reloaders Guide' read as such: "Test Barrel 8"; CCI 500 Primers; Hyd. 125 XTP; OAL 1.570"; Start Chg. No. 7 11.9 Gn. Vel. 1596; Max Chg. 13.2 Gn. Vel. 1735." I would think No. 2 or No. 5 might be more appropriate for use in a 2" revolver.

D R

 

[Walkalong]

Check with Accurate.

 

[baz]

I would think No. 2 or No. 5 might be more appropriate for use in a 2" revolver.

Would you explain to me why? (I'm not challenging you. I'm a n00b looking to be educated. I'm going to guess it has to do with burn rate, but an explanation of why this would make a difference with respect to barrel length would be appreciated.)

I chose #7 because the fps were marginally better than with #5 (more so wrt #2) with marginally less pressure (again, more so wrt #2). For instance, with #7 versus #2, the reported fps was 1374 vs. 1292, while the pressure was 42700 versus 43800. The differences were less with #7 vs. #5. And they are all probably so close as to be practically negligible.

If there's a case to be made for using #2 or #5 rather than #9, I'm open to hearing it.

Check with Accurate.

What for? Or, what's your point? All you did was point me to a web site I'm already familiar with. That's where I got some of the data in the OP. Are you saying I should ask them why Hornady has published data with Accurate Powder's powder that differs from what Accurate Powder has published using Hornady's bullets? Why not tell me to "Check with Accurate." I don't know if you were intentionally terse or not, but your response contributed nothing to my attempt to learn from the more knowledgeable members of this forum.

 

[Walkalong]

Quote:
Originally Posted by Walkalong
Check with Accurate.

What for? Or, what's your point? All you did was point me to a web site I'm already familiar with

Excuse me baz. Didn't mean to irritate you. Didn't think it was "terse", short and to the point is all. I guess my point is I would follow Accurate's data when others showed different data. I did not see where you mentioned Accurates data (I missed it, it was there, first line) so I thought I would link you up.

but your response contributed nothing to my attempt to learn from the more knowledgeable members of this forum.

Insulting me is a waste of time. I thought the link might be helpfull. Obviously it was something you have already studied. You seem to have taken it personal. I think that you are a being a bit sensitive. I learned to leave my feelings in the truck a long time ago. I will shut up now and let the "more knowledgeable" folks try to help you out. Good luck with your question. You are right. There are many knowledeable folks on this forum that can help you out. I am sure they will.

 

[jfh]

and I am going to muddy the water even more--

I have found one can locate two types of 357 loads--one is for mild 125 gr. loads with cast bullets--say out to about 24000 CUP--and the other is the firewall type starting at about 30,000 and going up to 42,000 or so with (typically) the Hornady 140 XTP. IOW, there is a big hole in the data.

I have both a S&W 640 and a M&P 340. I use the 640 for testing loads, and then shoot that load in the 340. I have no desire to shoot firewall loads in either revolver; I carry the 340 and do not anticipate stoking a 13.3-oz revolver with hot .357 / 125-grain SD loads. For now, my carry load is the Federal 110 gr. 38SPL PD load, and as I acclimate I will upgrade the Speer 135-gr. 38SPL+P load.

I am currently working on these reloading goals:

1. To produce a practice round that will replicate the Speer GDJHP-SB 135gr. load in 38SPL+P, and

2. To develop a (slightly-less performing) round using Win 231--of which I have a lot on hand. This one I call the "acclimation" round.

It has also occurred to me that if I can build these rounds in a .357 case, I will probably have somewhat less (cylinder) cleaning to do.

After wandering around a bit, I did find the Speer reloading data for the Gold Dot SB bullets. I've also gotten 300 of the Speer 135-gr. bullets, and a 1000 of Chey Cast 140 gr. cast FPs.

In 38 SPL, I can load up either bullet--the GD135JHP or the CC L135--with AA#5 per Speer's data sheet, and WSPs and get something close to 'duplication' with the 38+P factory round in perceived recoil and feel. All three--factory ammo, and these two reloads--shoot to the same POA in the 640 and generate nominally 1.25" groups at 10 yards. In the 640, the sweet spot appears to be about 6.8 gr with the GD135s; with the L140, it appears to be about 6.0 gr. It's a stout round in the 340, but I can shoot a cylinderful and be willing to reload, at this stage in acclimation.

After listening to others on another forum, I've also tried these loads in a .357 cartridge. That too looks promising. The POA changes, of course.

Unfortunately, when I was at the range this afternoon I could not set up the chronograph--others were shooting as well. But, AFAICT, these are 'mid-power .357 loads that may generate about 24,000 CUP or so.

Practice rounds with the Speer bullet are about 23 cents or so; with the Chey Cast 140, perhaps 10 cents. A 231 practice load will cost me about 7 cents--I got a lot of components fifteen years ago.

Needless to say, that compares favorably with the nominal $1.00 per round of the factory ammo.

I'm not too sure how my experience applies to your 125-gr 357 loads--you might jump up to AA#5 if you have some and don't want max power 357s. I do know there is less data for Accurate powders than we would like.

Also, you can try checking the Lyman Pistol & Revolver data, third edition. I've also gleaned some info there.

Jim H.

 

[D R Greysun]

Baz,

"Would you explain to me why? (I'm not challenging you. I'm a n00b looking to be educated. I'm going to guess it has to do with burn rate, but an explanation of why this would make a difference with respect to barrel length would be appreciated.)

I chose #7 because the fps were marginally better than with #5 (more so wrt #2) with marginally less pressure (again, more so wrt #2). For instance, with #7 versus #2, the reported fps was 1374 vs. 1292, while the pressure was 42700 versus 43800. The differences were less with #7 vs. #5. And they are all probably so close as to be practically negligible.

If there's a case to be made for using #2 or #5 rather than #9, I'm open to hearing it."

Hey, chill out! You pretty much answered your own question. I think you over looked the 4 to 6 inch barrel factor. Powder burn rate has a lot to do with selecting a powder. With a 2 in. barrel # 7 will be burning long after the bullet has left the barrel. It is doubtful it will have time to reach it's potential. Not to mention the fire ball. Using # 2 in a 2 in. barrel may not provide enough time to reach full pressure. It will however most likely make more pressure than # 7 and pressure is speed. The thing to do is dyno each load with your chronograph. Balance is what you are looking for. IIRC, you said you wanted something faster than .38 Spl. +P but not full Mag. power. +P is what 950-1000 fps with a 125 Gn. bullet from a lets say 6 in. barrel. From a 2 in. barrel you're already down 150-200 fps. So, you're looking at getting back to 850-900 fps realistly. I think you should be able to get there with # 2. It's a little bulkier than # 5 but volume wise it's a wash. They will both be laying on the side of the case, more so with a 357 than with a 38. I hope you can makes some since of this and it will help you with your decision on which powder to chose.

D R

 

[CZ57]

Baz, I don't want to do a discertation, but if I must, I will. Short and sweet? If you want to get performance as good or better than a factory load with a 2-3" barelled .357 Magnum, you probably won't find a better powder. Personally, I use the 140 gr. Rem. SJHP with 11.0 grains. It is superbly accurate, flashes a hell of a lot less than factory ammo, or the guy's loads who think you need to be using a powder like 2400, 110 or 296, and you will get higher velocity in a shorter barrel than you can get with a "magnum" powder. The data from Accurate was obtained with a S&W 686 with a 6" barrel. Not like Hodgdon data that came from a 10" closed breech barrel. In other words, you won't have to use a Thompson Contender to approach advertised ballistics.

 

[D R Greysun]

Here you will find a couple of links that I feel need to be considered. There have been some numbers thrown around this thread that can be misleading. Hopefully this will provide some perspective.

http://en.wikipedia.org/wiki/Copper_units_of_pressure

http://www.handloads.com/misc/saami.htm

I for one feel it has come to the point where load data should be displayed with PSIG units only. It's time to do away with CUP and standardized with PSIG units. Just my NSHO!

As a side note, it appears Accurate # 2 is no longer recommended for any .357 Magumn loads! I refer to: NEW: Accurate Load Guide Version 3.2: Page 4. With this in mind I withdraw my recommendation above with regard to Accurate #2!

http://www.accuratepowder.com/data/AccurateGuideV3-2.pdf


D R

 

[Master Blaster]

My two cents, on AA pistol powders;

a longtime reloader I know told me that accurate powders can be excellent performers, but they are very sensitive and can quickly develop over pressure with a small increase in the load.

They are unforgiving powders. The load data that was posted here shows this, great differences in starting and max loads, some starters being max loads or over max, in other data sets.
This shows a great sensitivity to component selection IMHO, and so if you use these powders stick to the exact components used in the loads in your manual.

One thing left out tin the loads is wether they recommended specific magnum primers. Could make a big difference.



JFH you wanted to duplicate the speer 135gdhp +p load:

Here is the source for my recipe:

http://www.speer-bullets.com/pdf/ReloadingSupplementalDATA/38s135GD.pdf

Speer put out data for this bullet awhile back and I loaded some with unique and with universal clays based on this data.
My thought was that they developed this load with a 6" barrel, so a faster powder might do a little better in a shorter barrel like my 642 2" than a slower powder like AA7, and have a little less flash.

BTW I have been loading and shooting the 135 gdhp short barrel bullet with 5.2 grains of unique with a WSP. It very closely duplicates the feel of the factory load in my 642.

 

[CZ57]

Tell him to put the pipe down. He doesn't know what the F%^& he's talkin' about!

 

[baz]

With a 2 in. barrel # 7 will be burning long after the bullet has left the barrel. It is doubtful it will have time to reach it's potential. Not to mention the fire ball.

This is information I can use. I don't actually recall the fireball, but I've been concentrating on other things. I'll watch for it. It would make a difference, wouldn't it, if I'm using a load at the bottom end of the range? I.e., less powder to burn, less likelihood of a fireball?

As a side note, it appears Accurate # 2 is no longer recommended for any .357 Magumn loads! I refer to: NEW: Accurate Load Guide Version 3.2: Page 4. With this in mind I withdraw my recommendation above with regard to Accurate #2!

Interesting. I have the latest, but hadn't really noticed that #2 wasn't there, since I wasn't considering #2 to begin with. What I did note about the latest was that this is the first time I've seen them use magnum primers (WSPM). It's always been CCI 500, before. Speaking of which:

One thing left out tin the loads is wether they recommended specific magnum primers. Could make a big difference.

I did list the primers in the OP. Now what's odd, to me, is that between the latest Accurate Powders load data, where they use WSPM, and the earlier one where they use CCI 500, the ballistics are exactly the same: 10.4 gr of #2 gives 1369 fps, 11.9 gr of #7 gives 1374 fps, same max load pressures, etc. Isn't that remarkable, that supposedly a new round of tests, with different primers, would yield exactly the same results at every point? It actually strikes me as incredulous, and makes me wonder if they aren't publishing some "extrapolated" data of some kind from "theoretical" results.

 

[Master Blaster]

I have seen loads in .357 magnum where the difference between a standard and a magnum primer is like 7,000 cup with the same powder and charge weight. Not sure if standard primers would differ a great deal.

My apologies to any AA powder lovers I may have offended, I am only repeating the opinion of another reloader.