I worked up a load last June for my 686 using Lyman data, 2400, and Hornady 140gr xtp. Max was 16.5gr. I started at 14.5 and worked up. All shot well then. No bad pressure signs so i loaded up 70 pcs with 16.0.

I just picked up a nice 66 2.5 last week and took it to the range today. I took along the 686 just to compare the recoil. I loaded them both with some factory 158gr factory Blasers to compare. The recoil on the 66 was harsh but manageable.

I dropped a cylinder full of the reloads in both and went to the line. The first one I touched off with the 686 really surprised me. Recoil and noise was substantially greater than the factories. Enough to make me stop and check out the case. The primer was cratered showing flow back into the firing pin hole. I packed them up and came home.

I got on Alliant's website and found that their max load for 2400 with a 140gr jacketed bullet is 15.1gr. ***?? That's like a 9% difference.

Lesson learned. Consult more than one source.

You may just be running into data that was shot to the two different pressure standards. Specifically Piezio PSI and copper crusher CUP. In my experience the older CUP data is much hotter. But be warned PSI and CUP measurements don't track and vary from one cartridge to the next, no formula to convert from one to the other. Checking multiple sources of data is best practice and should be done whenever possible.

Mark in GA

I am quite familiar with Lyman's data for 357 Magnum and it was run using the copper crusher method for determining pressure. IMO this is an indication that this data dates back to the 50's or 60's and it is rather "hot". The problem with the Copper Crusher method for determining pressure is that it's not able to resolve very short duration spikes in pressure, which is why load tables developed using this method are in general "hotter" than loads that were developed using the new piezo testing sensors. Basically, the newer data is more conservative because of observed short term spikes that were "visible" using the older method.

So, what to do. It's simple and exactly what you have learned to do. Don't feel bad, Lyman caught me in that exact same sucker hole. The good news is that I don't believe that the Lyman data is unsafe for a modern L of N frame but it will shorten case life and 357 Magnum cases can be hard to come by at times. In addition I've found that trying to push the maximum load potential is a bit wasteful of powder and usually doesn't produce loads as accurate as something loaded a bit more conservatively. So it doesn't bother me a bit to load 50 fps under the maximum, I get to save a bit of powder and I get a load that is easier on my wrists, ears, and cases.

I'll be honest with y'all. MrsG snatched the 66 up and said "That looks like my new purse gun!" I'll load it with factories for the purse but evidently I need a 'close to factory' range round for her to practice with. I have plenty of 158gr lead swc/hps.

Going by the account in post 1, I'm thinking that you got crossed up just prior to committing to the run load.
If you worked up to it properly, there would be no surprises like this.
Could be that you read 15 on the scale in development, but thought 16.
Could also be a failure to zero the scale.

Guess that means you have a few bench gremlins to hunt down.

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it just needs more voltage

That was my first thought since it had been awhile since I had loaded them. Checked the Lyman manual when I got home. 16.5 grs.

I think you have to remember that all loads are safe, but may not work as well for some guns as other. Full blast .357 isn't recommended for a model 19. An 'N' frame could probably handle these with ease. Even between guns of the same make and model is ACTUAL barrel internal diameter and the size of the cylinder gap are variables. A loose barrel and a large gap could mean a gun can be loaded really hot. A tight barrel and and tight gap is going to develop higher pressure.

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"He was kinda funny lookin'"

In my 686 L frame I shot six 158 xtp with 14.9grs of 2400
but 14.5grs was a lot more accurate.

I have 15grs of 2400 powder logged to try with a 140 xtp but
have not got around to it do to no bullets on hand as yet.

Thanks for the heads up.......
I will start with 14.5grs and see what my chrony reading come up with.
A factory load runs around 1350 fps.

Stay safe.

That's what I've used for years (Speer #9) & currently use it in my 686-6 without issue. Apparently Speer lowered that load by the time I bought #13. If you hadn't noticed, Alliant's reloading data is the exact same as Speer's, since they use their bullets, as well as both being part of ATK Sporting Group.

Hornady #8 is 15.5gr, Lyman #49 is 16.5gr, but Sierra #5-v6 is 17.4grs !! .

It's odd the work-up loads didn't have the same trouble. Could the temperature have been a factor?

Like's been said, some guns max out before others.

.

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Waiting for the break of day

I'm fairly confident the Lyman data is not over-pressure. The problem as I see it is, you are comparing full power loads you loaded with weak Blaser ammo which is not hot at all. For far too many years we have been deprived of the full potential of the ammo we choose to shoot. It's a shame but .357 Magnum ammo is supposed to be that stout.

BTW, why would you jump from 14.5gr right up to 16.0gr 2400? Wouldn't it have been better to go to 15.0gr and 15.5gr first?

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Freedom is never free!!
SWCA #3437

Current Alliant data is not data actually developed by Alliant but just
data copied from the Speer manual. The older Lyman maximum of 16.5
grs shows less pressure than several other loads they list and were
considered safe and normal when developed.

I am new to reloading so maybe I don't know what i am talking about, but I always load on the LOW end, not the high. I'm putting a hole in paper, why waste more powder than I need to plus possibly ruin a gun? My data for Red Dot under a 158 grain LSWC .38 calls for 3.0-3.4 for regular .38, 3.8 for plus P. I load 3.1-3.2 max.

But yeah, check more than one source. Good thing you didnt fire that out of your 66.

I heave learned two things from loading 357 Magnums.

1) Five rounds is NOT enough to evaluate the performance of a particular load. I loaded up 5 rounds of Hornady 140 XTP's using Lyman data and they looked good. However and expanded test using a 30 round batch revealed that 1 in 4 cases were difficult to extract. Backing off the powder charge 3/10 grains solved that problem and the ammo was more accurate.

2) You don't need to push the limits with this caliber. Fact is a 158 grain bullet moving at 1200 fps. from a 6 inch barrel is plenty powerful enough for anything one would use a 357 Magnum for. My pet load for my 1892 Winchester is one that some might considered too weak to be safe, because it's just 14.8 grains of H110 with a 158 Hornady grain Hornady XTP. Per Lyman's data that load is about 1.5 grains below their minimum. However, it's a high/mid range load per Hornady and it will group 1 inch at 50 yards from the Winchester and clocks 1610 fps. from it's 20 inch barrel. BTW, it also clocks 1200 fps from my 6 inch Dan Wesson.

When I started loading I was told to treat each gun as a separate entity. What works in one might not in another. This is important when your loads are getting near max load data. In the early years my Colt GM made a nice ringing sound with a couple of 45ACP/Unique loads. I had prepared for this with my bullet puller eliminator..... a Ruger Blackhawk convertible.
ElleMae still gets a kick out of that purchase.
Safety has no budget.

Similar problem with my 9 mm I was firing at the range everything going fine till I hit one that was hotter than the others used Titegroup .4.7 gr 115 RN plated Extremes after that my Sig 226 would only fire about every other round. Problem was the metal from the primer blocked the firing pin chamber, cleared it out ,pin was ok gun shot fine worried me , You cant be too careful when reloading

Was the Blazer ammo the aluminum cased stuff? I bought some this summer and found it to be quite mild. Not a great cartridge to compare against.

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Common sense isn't so common.

Well you said you worked the load up. If so, you would have seen pressure signs approaching the top end. Yes, using multiple sources is important. When I am working a new load up, I use data from 2-3 sources, avg the middle & top end. Then work up to the top end from middle data, if that is where I want to go.
All guns are diff, one reason data is all over the place. With max loads, everything matters; case manuf, primer brand, OAL, test temp, elev above see level, it all comes into play when running the top end.

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NRA Cert. Inst. IDPA CSO

This just intended to be a friendly comment. There is nothing wrong with using 2400 in a 2 1/2" gun, but watch for unburned powder granules. 2400 seems to perform better in longer barrels. Try a medium burning powder for short barrels.

I once bought a bag of .357 Magnum ammo from a dealer at a gunshow. I knew the guy and trusted him a little. The ammo he sold was a large charge of Win. 231....just a tad too fast for heavy .357 loads. The flash and bang was pretty attention grabbing!

Load your short barrel ammo with a powder somewhere in between 231 and 2400.

Also, I have observed different revolvers will handle the same load very differently. If the revolver has loose chambers, that can cause setback like you experienced.

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Bob.
SWCA 1821

I have shot several thousand rounds of 140 gr bullets over 16.5 gr of 2400 back in the 70's when I was "searching" for the right loads....I ran a lot of those thru a 4" 65 and they were "intense"....as post #14 mentions....each and every gun is a different entity....having worked with thousands of different guns in several dozen platforms over 40 years as an instructor I can testify to that.....and as the previous post discusses 2400 in shorter bl's.....I use 2400 in 6" bl for magnum loads and then go to Unique in 4 or shorter.....burns more efficiently, does not have the tremendous muzzle flash or report that 2400 does in the shorter tubes....as pointed out by Bob in the above post...when running max loads, it is always a good idea to do that for each and every gun you are going to shoot them in. I have had some revolvers that digested one load just fine, then load that same load into another revolver and have the primer flow back and lock up the gun.

I really appreciate all the info and advice. As usual I have learned tons from you folks. I've loaded lots of 9mm, 45acp, 38spl, and 223 but have only worked up a few loads for 357. I'm just trying to be careful and do it the right way. I just wasn't comfortable with the look of the primer.

This is exactly what I was thinking when I read the OP. Blazer Alum .357 is incredibly mild stuff. 920fps from my 4" GP100.

I also don't quite follow your workup. You started at 14.5, worked up, but to where? To over 16?

Anyway, I'll also say that I use Federal regular primers and with 300MP (not 2400, but as close as I use), every load I have tested, from the starting load to max book data has had the primer flow back into the firing pin hole. It really doesn't seem that this is a useful way to gauge pressure, other than if it's grossly over and the primer is destroyed/etc.

I'm fairly new to reloading, but the notion of reading primers seems pretty specious to me.

From the pic, I see no issues with the primer. .357 mag in revolvers is known for flattening primers even with safe loads. That primer is far from flat. Reading primers in revolvers is like reading tea leaves in a cup and just as accurate. Sticky extraction is more of a sign of excess pressure.

The Lyman manual likes to run .357s hot. One reason I always reference at least 3 sources of published recipes while doing load development is because when one finds an extreme such as Lyman's, you know to be cautious. I also would have never loaded 70 rounds without loading just ten and then testing.

Reloading is a continuous learning experience and it is always better to error on the side of safety, than hoping to run a max load. You didn't say whether you used standard or magnum primers. I see the Lyman recipe calls for magnum. 2400 can get spikey when used with magnum primers and Alliant warns against using them with 2400.

Ive seen worse.
its cause for a raised eyebrow.
I wonder if the S&B brass has a smaller capacity than our usual suspects .... I haven't worked with it in 357 myself

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it just needs more voltage

The work up was 14.5, 15.0, 15.5, 16.0, 16.5.

+1;
Weird recess on that S&B primer area..... like a small step down
in the edge?

Looks like a standard pressure load to me.

What I am seeing in your photo is not abnormal in my experience....what you are seeing on your primer is not cause for concern IMO.....as pointed out in previous posts, reading primers can be misleading, there are a host of variables...such as how loose the primer pockets are....I have old brass that the primers fill the primer pocket and there are no rounded edges to the primer cup....simply flows and fills the primer pockets....if the primer flows back thru the breech face, it will form a "nipple" that will arrest the movement of the cylinder and tie up the revolver.....this usually requires the wooden mallet....and the "nipple" will be sheared off from the primer cup when you force the cylinder open...that is not what I see in your photo.....I have had this happen with magnum brass that had reached it's end of magnum loads........the load you are shooting is a max load and is unpleasant in short barrel K frames...as you discovered.

To bad you don't have a .357 lever rifle to test with. I like CCI primers for a warm load.

One of my favorite loads for my .357 Mag L frames is 13.0gr of 2400, a .358" 155gr LSWC with a standard Federal 100 primer. I bought a very nice six inch M-28-2 and that load locked it up tight and had to pound the case's out, thinking it may have a problem and checked it over closely and found nothing wrong. Well it turns out it just loves 15.0gr of H-110 a .358" 155gr LSWC and a CCI magnum primer. Now the H-110 load is a rather stout load and the M28 shoots it very well and the rather lighter 2400 load locks it up. Just goes to show how different firearms can be very different with the same load.

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Stay safe people!

Thanks again for all the info. It appears from what you guys say is that the load is safe but not recommended for the 66. That makes perfect sense to me. I'll shoot them in my 686. Should be a good hog round maybe.

Like I said, I worked up the load back in June and didn't notice anything out of the ordinary enough to note it in my book. I just checked out my Sierra manual, which is what I had back then along with the Lyman. Their max for a 140gr JHP with 2400 is 17.4. I suspect at that time I decided to go with the Lyman data just to be on the conservative side. From here on out I'll have at least one more data source if available.

Powder recommendations for the 2.5" 66? I have Bullseye, Unique, 231, Titegroup, Power Pistol, 2400, and H110.

Any of the first five you mention should do nicely for the 2.5 inch gun.

The poster who said safety has no budget said a mouthful. Well put!

I have had revolvers lock up with the start load. Some guns just dont like some components.

Temperature also can make a difference with some powders. A load worked up in cold temps can be over pressure when it is 95 degrees out.

Generally, the bullet makers loads would be correct. I have some 124gr 9mm bullets and I found loads of 5.0 gr max and 6.2 gr max of Unique. Also big variation in COL. I use the bullet makers load.

Good advice, but although elevation above sea level has a big effect on external ballistics, I don't believe it has a significant effect on peak pressure (internal ballistics).

Of those powders, probably Power Pistol.

I usually load HS-6 or Longshot for middle hot .357 Magnum ammo depending upon the bullet I'm using.

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Freedom is never free!!
SWCA #3437

I just checked my Hornady 9th edition manual and maximum charge for 2400 & Hornady 140gr XTP is 15.5gr @ est. 1350fps.

I use H110 for my 158gr Hornady XTP /FMJ-FP berry's bullets with 14gr H110. I've been very happy with those loads.

You're getting primer flow, which is never a good thing. No, it's not okay.

You can pull the bullets and weigh the charges from a couple of rounds to verify if you made an overt mistake in making that batch.

It's pretty much all been said here. I'll just reiterate what was said above... everything matters. A near-max load in one gun might be an over-max load in another, even of the same model.

One thing I frequently see is reloaders mixing components, especially brass. That's fine for mild, plinking ammo. But when you're working up a load with top accuracy and/or max velocity in mind, you want to keep everything same-same.

Same brass... not just the same brand, but the same lot and how many times it's been fired. Same lot of primer. Same lot of powder. Same lot of bullet.

Loads developed outside during the coolness of spring or fall (much less the cold of winter) will be noticeably hotter during the warm summer months. And you might surprise yourself with "summer pressures" even in the dead of winter, if that box was sitting on the dash or somewhere where the heater was blowing on it.

Loading for autoloaders... well, semi's have a narrower range of pressure tolerance. Too light or too hot and weapon malfunctions raise their head. Revolvers are quite a bit more flexible, but have their own idiosyncrasies. Dimensions in the cylinder, forcing cone, and bore influence things a lot. If you haven't slugged or otherwise measured those dimensions, you're kinda flying blind (which is not to say that an excellent load can't be empirically determined for that weapon, but when contemplating using that load in a different weapon, it's rather like throwing darts).

And, yeah, consensus matters. You can't have too many load manuals on the shelf.

Really nothing wrong with that primer imo. Primer flow can be just an over sized firing pin hole & that isnt much showing there.

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NRA Cert. Inst. IDPA CSO

1: Consult multiple load sources.
2: Check the test gun & barrel length used in the load data. Don't expect a load developed for a 7 1/2" Ruger single action to work the same in a S&W snub.
3: IF you plan on using 1 load in multiple guns, keep it on the milder side. (that's just me).
4: 2400 has always seemed to give me LOUD/HEAVIER recoil, if it weren't so fast & accurate...
5: To do it "right" work up different loads for different guns,
sometimes you get lucky, & 1 load will work well in multiple guns.
OUT OF CURIOSITY, was the outside temp WAY hotter than the first time you shot them?

And a lot of people would agree, but that's not always the case. I'm very much of an experimenter and like to try all kinds of bullets, powders and combinations. One thing I like about the old revolver cartridges is that they are so VERSATILE, which is why I have a .357. I stay within published limits and not take chances but I like the whole spectrum. My friend bought a big .44 mag and first I loaded .44 Special load. then a heavy .44 magnum load and then .44 special SWCs with a minimum of Titegroup.

It's like riding a big motorcycle. Some like the feeling of power and some like the feeling of controlling that power.

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"He was kinda funny lookin'"

Was there a significant temperature difference. There can be a difference in max loads with a 20 F temperature raise.

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Front sight and squeeze

Not really with most powders. Though if you worked your load up at an extreme temp diff, everything matters at max.

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NRA Cert. Inst. IDPA CSO

Lots of good info here, and I'm always happy to read it because this kinda stuff freaks me out. Lol.

I am anal about cross referencing loads, 2, 3 different other sources. May have already been said, but make sure it wasnt a "Ruger only" load.

Also, may want to join loaddata dot com. I think it's about $30? Tons of loads. But a good place to cross reference.... so much so it's almost redundant, lol. I have books,too. If you print it out, expect like 50 pages of loads. Or you can search by bullet weight. But if you do this, beware that some recipes will have the same molds, but have 157 grain and another label 158 grain. So this is kinda tough compare to just scrolling through it.

I shoot 16.0gr 2400 behind a 140gr Sierra JHP in my 6 inch 686-6. This is the loudest magnum load I have ever shot. Believe it or not with all that noise and flash comes great accuracy. In case your wondering it's leaving the barrel around 1450 fps in my revolver.

As OP mentioned Alliant's max is 15.1 for 140gr as for loaddata me personally wouldn't waste money on that - every powder manufacturer have their own free manual plus free hodgdonreloading.com plus any paper manual for that $30 will cover 99.9% of your needs.

Dang dieseltech!! You're almost in 10mm territory if I remember correctly. That's awesome!! The more I reloaded for my 10mm, the less I was impressed vs my 357 and other calibers.

Iouri, I have manuals. And cross reference with manufacturers sites. Like I said. I'm just really paranoid. Haha. Also, they do tend to have some crazy loads in there, all in one place. Honestly, I spent the money, but then printed everything off for 38spl, 357 and 9mm. So, same price as 3 books with about 10 books worth of data for each caliber. Good deal imho. Also a good site for oddball like ventouri and Oregan Trail, etc. While I dont use these oddball components. Nice to have if there's another shortage. Were comfortable now, but could happen again.