Range Report: 357Mag; 125 JHP; AA#7

[Nick_C_S]

For a couple months now, I've been tossing around the idea of doing a load work up for 357 Magnum, using Speer's 125gn JHP (UCHP techinically; #4013), and AA#7 propellant.

I like heavy bullets; so I haven't done a lot of work-ups with 125's. 158's are king in my 357 world. I have chonographed factory ammo 125's and got velocities over 1400 f/s (4" bbl). Speer's 125 GDHP's chrono at 1460 f/s; and Federal's "low recoil" 130 Hydra-Shok's deliver the goods at 1430 f/s. I've got a bit of an itch to emulate such performance.

First thing I did was look up load data (of course). Immediately, I ran into some contradiction:

Hornady shows it from 10.5 to 11.5
Speer shows it from 12.0 to 13.5
Sierra shows it from 12.5 to 13.7
Accurate (on line) shows it from 10.5 to 12.1
QuickLoad calculated pressures seemingly in alignment with Speer.

Because of the differences in data, I chose to play it fairly safe and start at 11.0 grains. Because I don't like pulling bullets, the work up took three trips to the range: 5/13; 5/15; & 5/18.

Gun: Smith 686 4" bbl.
Brass: Mixed (mostly WW and Fed), nickel, old, and trimmed to 1.280".
Bullet: Speer 125 grain UCHP #4013; seated deep in the cannelure to an OAL of 1.552"; with a generous roll crimp.
Primer: CCI 500
Chronograph: Chrony Beta; at 4 yards; diffusers in direct sunlight.

First trip was just 6 rounds at 11.0 grains.
Second trip was 6 rounds each at 11.4; 11.7; & 12.0 grains.
Third trip was 10 rounds each at 12.0; 12.2; and 12.4 grains.

Here's the numbers:

11.0 grains: 1308 f/s, 14.60 SD

11.4 grains: 1347 f/s, 16.10 SD
11.7 grains: 1367 f/s, 5.50 SD
12.0 grains: 1385 f/s, 12.55 SD; slighty sticky extraction.

12.0 grains: 1406 f/s, 32.91 SD; slightly sticky extraction.
12.2 grains: 1418 f/s, 31.60 SD; slighty sticky extraction; flattened primers.
12.4 grains: 1422 f/s, 1615 SD; sticky extraction; flattened primers.

Recoil was manageable, and report was rather tame. The feel and sound suggested a powder faster than the "magnum" kind (2400, W296, 4227, etc.); which it is, of course.

Couple things: This particular firearm tends toward sticky case extraction - for whatever reason. On numerous occasions, I have had sticky case extractions with this gun, and not with my other three 357 Mags (another 686; a 686+; and a Colt Python), digesting the same ammo. So minor sticky case extractions with this gun doesn't really alarm me.

Also, over my years of chronographing, I noticed that the barrel seems to increase in resistance as jacketed bullets are shot through the gun. I've shot 60 rounds of the same ammo once (just happened to be the same Speer 125 UCHP bullet), and velocities steadily decreased from round one to sixty. I believe this accounts for some of the 21 f/s difference between the two 12.0 grain loadings (the first day, the 12.0 was shot at the end of the session; and the second day, the 12.0 was shot at the beginning of the session. The gun was cleaned between sessions.) And I believe it accounts for some velocity loss with the 12.2; and especially, the 12.4 loading.

Conclusion: as much as I'd like to do some more chronographing at the same charge weights to answer some lingering questions; it's not likely to happen. I believe pressures are excessive at 12.0 grains and beyond. With this combination (357/125), AA#7 seems to behave with a faster burn rate than I expected. I am extremely pleased with its performance with 10mm/180; and so my expectations were high for this work up. They weren't met. I did not get the expected velocities.

Next steps: I dunno . My next slower propellant is 2400; and I'm not really keen on using 2400 with such a light bullet. I suspect there would be a lot of flash and recoil . These days, "range fireworks" don't do much for me. I wish I had whatever propellant Speer and Federal are using - because they behave just like these AA#7 rounds, except with a good deal more velocity.

 

[Dufus]

I don't shoot anything that light in the 357, but Alliant's 300-MP might get the velocities to equal the factory rounds.

Seeing how Speer and Alliant are in the same family, makes sense to me.

I bought my 1st one in 1975 and have not shot any factory rounds in any of them.

I think my son has shot 1/2 box in one of the Black Hawks.

 

[44 AMP]

Try going to AA#9 slower than #7, a bit quicker than 2400 or WW296 or H110.

Blast and flash are what the .357 is about!

If you want top velocities, you're going to get blast and recoil, though flash will vary a bit with the specific powders used.

AA#7 is a medium powder, like Unique, it hits top pressure before reaching top end velocities in most cartridges.

I have one 4" .357, don't shoot it much, the rest of mine are all 6" or longer.

Max charges of 2400 will get you 1600fps+ from a 6" with the 125gr JHP. NOT SUITABLE FOR ALL GUNS!!!!

Loads at that level have proven too hot for K frame guns I've tried (Model 19/66) but work fine in a model 28, though they are smoking HOT.

Ammo makers buy powder by the ton (literally) and can create loads that the reloader using regular canister powder simply cannot duplicate sometimes. This has always been the case, and is just something one has to live with.

I'm confident you'll get the 1400fps you're looking for with a powder a little slower than AA#7.

I noticed that the barrel seems to increase in resistance as jacketed bullets are shot through the gun. I've shot 60 rounds of the same ammo once (just happened to be the same Speer 125 UCHP bullet), and velocities steadily decreased from round one to sixty.

Might be due to HEAT, rather than jacketed bullets, directly. The barrel heats up, expands slightly (bore dia. gets fractionally smaller), grips the bullet a little tighter, more friction, less velocity.

 

[Nick_C_S]

Try going to AA#9 slower than #7, a bit quicker than 2400 or WW296 or H110.

I'd try AA#9 except I'm trying to reduce the numbers of different propellants in my inventory, not increase. So I'm going to make due with what I have. I have no doubt that W296 /H-110 would do it, except it is one of the propellants I have already retired from my inventory. My supply of W296 is completely exhausted - still have loaded ammo though.

Blast and flash are what the .357 is about!

Yeah, I get that. At 54 years old, I still have an occasional recoil junkie day or two. But usually, I'm looking for something a little more . . . "balanced."

If you want top velocities, you're going to get blast and recoil, though flash will vary a bit with the specific powders used.

Yep. Life is full of compromises.

AA#7 is a medium powder, like Unique

It's slower than Unique - at least, in my experience. I consider it a "slow" (not to be confused with "magnum") handgun propellant; albeit, on the fast edge of the category. If it was any faster, I'd place it in the "intermediate" category.

it hits top pressure before reaching top end velocities in most cartridges.

True. Hence, were I categorize it in the burn rate spectrum.

I have one 4" .357, don't shoot it much, the rest of mine are all 6" or longer.

I have an 8-3/8" 686; and for that, I bust out the magnum powders on a regular basis. Well, "regular basis," considering it's a safe queen these days.

Loads at that level have proven too hot for K frame guns I've tried (Model 19/66) but work fine in a model 28, though they are smoking HOT.

I only have one K-frame (unfortunately), and it's chambered for 38 Special (Model 67). If I did have a K-frame 357 Mag, it wouldn't get fed the hot stuff.

Ammo makers buy powder by the ton (literally) and can create loads that the reloader using regular canister powder simply cannot duplicate sometimes. This has always been the case, and is just something one has to live with.

I know .

I'm confident you'll get the 1400fps you're looking for with a powder a little slower than AA#7.

My only other choice is 2400 - due to the aforementioned self-imposed propellant restriction. I have tested one loading of 125/2400 - Speer's starting charge of 16.5 grains; yielded a lakadaisical 1340 f/s. Sounded low-pitched and weak. Of course, it's just a starting load; but at least I already have my baseline, if I want to go down that road.

That said, I don't know if I'll pursue this any further. It's not like it's a vision-quest or bucket-list item. No sleep will be lost either way. Besides, AA7 will get the 125's in the 1360 f/s range safely; and that's nothing to sneeze at - still a pretty potent round. And the gun handles really nice doing it. So there's that.

Thanks for the feedback. It's always good to get another's perspective.

 

[SHR970]

Nick

As the bullets you are using 'feature' UniCore technology what you are in fact using are PLATED bullets with all that goes with them. That is why you are running into pressure signs earlier then expected.

Having used Winchester JHP 125 gr. I have run straight to Speer #12 book max. 13.5 gr. AA#7 using batches that were sourced from Israel, RSA, Czech., and US.

I've done this using both Win and Fed. Brass and either CCI500 or WSP primers. I've run this load for years out of my SP101 3".

I just proves that when you change components, you have to work it back up. In this case the bullet itself is the limiting factor.

 

[SHR970]

44 AMP wrote:AA#7 is a medium powder, like Unique, it hits top pressure before reaching top end velocities in most cartridges.

Not even close... AA#5 is more like Unique... AA#7 is more like Blue Dot & 800X

 

[44 AMP]

I have tested one loading of 125/2400 - Speer's starting charge of 16.5 grains; yielded a lakadaisical 1340 f/s.

This was out of the 4"?

You won't get full performance out of 2400 from a 4" barrel. Clock it from the 8" tube and see what a difference it makes! Also, while I may not need to, I use magnum primers with my 2400 loads.

44 AMP now writes:AA#7 is a medium powder, it is like Unique, in that it hits top pressure before reaching top end velocities in most cartridges.

I put AA#7 at the slow end of the "medium range". You might put it at the fast end of the slow range, but I don't.

what you are in fact using are PLATED bullets with all that goes with them

wait..what??? you're using PLATED BULLETS????

Ok, all bets are off, forget my advice, I thought you were using jacketed 125gr. Never mind. I don't (and won't) use plated bullets for anything serious. Good Luck, son, you're on your own...

 

[Nick_C_S]

wait..what??? you're using PLATED BULLETS????

I'm using Speer's UCHP's. If they're plated, they're an extremely thick plating. They are the closest thing to a JHP that Speer offers. I consider them jacketed - and the load data supports this. Although I think they're "molecularly bonded" or whatever. Certainly not a "plated bullet" in the common sense of the term - such as X-treme's products. They bear no resemblance in construction to something like that.

I do have Hornady's 125 XTP's. Maybe I'll go down that road. They sit about 20-thousandths less deep in the case (at the cannelure), so would likely slow the burn rate just a touch and require a little more charge. Might be worth a try.

Re AA7:
"On the fast side of the slow powders."
"On the slow side of the medium powders."
Fair enough.

 

[zeke]

Am fond of aa-7 with 125 jhps in 357. Speer's gold dots usually have higher pressure than regular plated bullets same charges. Higher coefficient of friction imo. Am willing to sacrifice a little velocity for the accuracy, and less blast/concussion with aa-7.

Prefer the regular 125 jhp's in 357, like Winchester's.

 

[Nick_C_S]

Re: 125gn w/ 16.5 grains of 2400; 1340 f/s . . .

This was out of the 4"?

Yes. With 357, I do all my work ups with my 4" bbl. Not until after I find the "right load," will I bring out the 3", 4", & 8-3/8" for a side-by-side comparison of the ammo. I don't shoot my 8" enough to make ammo specific for it.

Keep in mind, this (the 16.5 grains) was just the starting load from the Speer manual. I loaded 10 rounds to take to the range, only because I was chronographing a small quantity of other stuff and needed more fodder to make the range trip worth while. So I loaded up 10 real quick. It wasn't a "load work up" in the classic sense of the term. It was just one loading - just a start.

You won't get full performance out of 2400 from a 4" barrel.

Yeah, I know. That's why I'm reluctant to go down that road. It does better with 158's, but still . . . a bit slow.

Also, while I may not need to, I use magnum primers with my 2400 loads.

I don't. That's one of the reasons (there are others) why I phased out W296 in favor of 2400. Not only am I trying to simplify my propellant inventory, I'm also trying to simplify my primer inventory .

 

[SHR970]

One difference between pure copper and gulding metal alloy is the coefficient of friction.

I don't care about the difference of plating thickness vs. other manufacturers.. what I care about is jacket coeficient and core alloy hardness. Cup and core bullets are jaded towards jacket alloy coefficint of friction.

UniCore or Gold Dot... Same thing. Play by the Plated Rules. This goes back to at least Speer #12. Jacket thickness is only one aspect. Alloy is another and that 5-10 % zinc is a major factor. .

 

[Nick_C_S]

Switched to XTP's.

Since I was getting a little less performance than I wanted/expected with the Speer UCHP's, I decided to switch to Hornady 125 grain XTP bullets. Since they sit 20 thousandths less deep at the cannelure, I figured that they may accept a little more charge than the Speer UCHP's - even tough Hornady's load data shows much less; hence, the following . . .

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

And to use my own words: Please do your own load work up. Use my data for general information only. Do not use my data for your ammunition loading.

Hornady 9th runs from 10.5 to 11.5 grains for their 125 XTP. Since I've been has high as 12.4 with Speer's UCHP's; and QL estimates only 26Kpsi with 125 XTP's using 12.4 grains of AA7. Furthermore, many other publications are showing charge weights similar to mine - and well beyond. With all that, my first batch was only 6 rounds each at 11.8 and 12.0 grains. On 5/26 . . .

(Same gun, 4" bbl)
11.8 - 1407 f/s; 18.05 SD. Slightly flattened primers. Higher than expected result.
12.0 - 1394 f/s; 22.20 SD. Slight flattened primers; slightly sticky extraction.
Performance was basically the same compared to the UCHP's. I found it odd that the 11.8 had a higher average velocity, but it was only 6 rounds, and stuff happens.

Next step: I loaded 10 each at 12.0; 12.2; & 12.4 grains. On 5/28 (today) . . .

12.0 - 1396 f/s; 9.99 SD. Slightly flattened primers. Slightly sticky extraction.
12.2 - 1419 f/s; 28.78 SD. Slightly flattened primers. Sticky extraction.
12.4 - 1425 f/s; 21.71 SD. Pancake flat primers. VERY difficult extraction.

Needless to say. That's the last time I'll get near 12.4 - which is clearly over pressure. They also left a sharp case bulge near the headstamp. Pressure had to be brutal.

So I'm definitely switching to XTP's. My set loading is going to be either 11.8 grains or 12.0 grains. The next step is to load and test 20 of each and decide then.

Either way, they're running near 1400 f/s and that's plenty for me. What is particularly impressive is how well the gun handles relative to the velocity. For being at 1400's doorstep, these behave surprisingly tame.

 

[Hammerhead]

Good stuff Nick.

I'm also trying out 125 jacketed (Sierra SP) and plated (Rainier FP) in my 4" single action.

Unique works great of course, but I don't like pushing Unique to full power in 357, it's a medium power only fuel for me.

Tried Power Pistol, too much blast and recoil for the power level you get.

HS-6 works well, gives good velocities and low recoil/blast, but needs a magnum primer, even then it's dirty, but it's a good safe 'magnum lite' powder.

Might give AA7 a try, no magnum primer needed you say? that's a bonus for me. Plus someone else has done the chrono work

 

[Nick_C_S]

HS-6 works well, gives good velocities and low recoil/blast, but needs a magnum primer, even then it's dirty, but it's a good safe 'magnum lite' powder.

"Magnum lite" - good way to describe it. Good description all around. In my workups with HS-6/125's, I found it rather wonky however. I get a lot of velocity spread and never could find a spot where it "settled down." It was almost like it lacked crimp - even though the crimp was very robust.

With the 158's however, I found the results quite pleasing. 9.0 grains under 158 JHP's (or JSP's) is a pet load of mine. Rarely do I bring one of my 357's out to the range without a box of my HS-6/158's coming along for the ride. Shot some today, in fact.

1068 f/s 3"; 1137 f/s 4"; & 1128 f/s 8-3/8." Notice, the 8" bbl shows a lower velocity (all guns 686's). That tells me the load is making good use of the propellant. Peak velocity would probably be with a 6" but I don't have one (well, I have a 6" Python; but it's a safe queen). I digress. Anyway, I load a lot of them. Good loading - HS-6 performs best with heavy bullets.

Might give AA7 a try

It's good stuff. I do think it's better suited for semi-autos, however. I am really pleased with it pushing 180 grainers in 10mm. And I bet it would work great with 147's/9mm - or 357 Sig, for that matter. That's its wheelhouse.

I did this workup because I wanted something that pushed 125's pretty hard, without using a big, booming, magnum propellant. I knew I would be pushing it in terms of pressure. I was right.

 

[ligonierbill]

The only powder that duplicates commercial (Hornady) 125s from my 4" GP-100 is 300-MP. Sierra JHC went 1,460 vs the Hornady commercial at 1,430. No extraction or other problems. But since I proved to myself that it works, I'm back to loading 158 XTP or 140 Barnes XPB over AA#9, H110 or 300-MP (until I use it up). All of those work well, with similar velocity at or near 1,300. The 125s are going to the .38 Spl.

 

[Nick_C_S]

The only powder that duplicates commercial (Hornady) 125s from my 4" GP-100 is 300-MP.

I chose my words carefully. I mentioned in my original post that my purpose was to emulate factory defense ammo. I knew better than to attempt to duplicate it. Speer's 125 GDHP's clocked at 1460 though my 4". But it's a big round - probably uses your 300-MP (or whatever the non-canister grade equivalent is. Federal's Hydra-Shok's (130gn) seemed a little more tame - and that's more of what I wanted to emulate.

I've done well. I haven't landed exactly where I wanted, but I have made some plenty potent 125gn ammo that handles really nice. So I'm pleased.

I just loaded 20 rounds each at 11.8 grains, and 12.0 grains. I'll decide which charge weight will be the set amount after they all get passed over the chronograph.

 

[Nick_C_S]

I just loaded 20 rounds each at 11.8 grains, and 12.0 grains. I'll decide which charge weight will be the set amount after they all get passed over the chronograph.

Took the two loadings out to the range this morning for a chronograph session. This is the final step. 20 round samples of each.

11.8 grains: 1365 f/s; 16.51 SD.
12.0 grains: 1374 f/s; 10.63 SD. Nice standard deviation.

Just like all previous times, there was no extraction problems at 11.8; but had minor extraction problems at 12.0 - so that went exactly as expected. What didn't go as expected is the some-odd 19 f/s velocity loss from the previous sessions.

The ammo was cooler this time, as I put them out in the car (garaged) the previous night. And then I got to the range early, so they sat out in the coolest part of the day (shade) for about 45 minutes before I put them to work. I don't think that accounts for 19 f/s though. Maybe God had his thumb on the grain scale when I was loading them .

To be a bit more serious, I'm pretty careful with checking my charge weights - especially when doing a work up. I check-weighted the scale at 12 grains; and the die settings never moved from the previous sessions, so . . . It is what it is. I move on.

Anyway, I have decided on 11.8 grains as the set recipe. 1365 f/s is plenty of punch. As mentioned last post, I didn't land where intended. But I have a load recipe that's good and stout; and does so with relatively light recoil, no booming report, and no noticeable flash. A great handling 357 Magnum round.