Over pressure in 357 Mag with 296??

[ssyoumans]

I just got back from the range shooting my 6" GP100. If I am reading the cases right, the bottom row all show signs of excessive pressure, yet I am under the start charge for 296 with a 125gr JHP.
296 with a 125gr JHP and CCI Small Pistol Magnum Primers: Start 21.0gr, Max 22.0gr per Hodgdon's website.

I loaded these up at 20.3gr using a Remington 125gr JHP, but am concerned with the overpressure signs. My measured velocity out of the 6" barrel was 1494 fps, which seems right in line with where it should be.

Yes, I know you are not suppose to drop more than 3% below start charge when using 296, but the danger is a squib, NOT overpressure.

I also included some cases with 16.0gr of 2400 for 1453 fps. with the same 125gr Remington JHP. These do not show any issues at all.
BTW: at these pressure levels, 2400 generates much more flash out of my SP101 (which I was using as well) than the 296.

I am very leary of loading 21.0gr, much less 22.0gr of 296! Any thoughts on how I should progress if using 296? :banghead: My easy answer is stick with 2400

 

[rcmodel]

My advice would be to not go below the recommended Start load.

The danger is not just squib loads, but inconsistent pressure spikes.
Which you may be seeing.

It can also be that your pressure is so low, the primers are backing out, then the case slams back against the recoil shield, giving the flattened appearance when they are violently re-seated, with full chamber pressure trying to keep them from being re-seated.

1. Forget "reading primers" unless you are also an accomplished tea lief or palm reader.
For the rest of us, they both will tell you about the same thing.

2. Follow the published load data, and don't try to second guess the ballistics labs who pressure tested the Start & Max loads.

rc

 

[Clark]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

When I started handloading ~12 years ago, I did not know what would happen.
I saw that Hodgdon listed 22 gr 125 gr JHP for H110/W296 in 357 mag.

I put that load in an S&W 60 38 special, tied the revolver to a board, and got on the other side of a concrete wall to pull the trigger string. When the round went off I saw the revolver flying through the air, propelled with recoil coming back way over the wall and going some distance.

The revolver was ok, but the primer looked very top hat.
I could probably dig out that piece of brass and take a pic of the flat primer, but that would be a lot of work.


P.S.
I can reduce H110 loads in half, and no squib loads, if I do a real good roll crimp.

 

[ReloaderFred]

Those are normal looking primers for a Winchester 296 load, even though you went under the start load in your manual. Win. 296 is a slow powder, which means the pressure curve is a little longer. Flattened primers are normal with full power .357 Magnum loads. Look at the primers on factory ammunition and most of them will be flattened just like your primers.

Winchester doesn't (or didn't before Hodgdon bought the rights to the powder) recommend varying from their data at all. The load was the load, and as long as I stuck with their recommendations, I've never had sticking cases, etc. using Winchester 296 powder.

Hope this helps.

Fred

 

[Slamfire]

Reading pressure signs from primers is unreliable. Still I look at them and try to devine the mysteries revealed. Reading tea leaves is better as you get to drink a nice cup of tea.

I too use my chronograph. If I am getting velocities above published values, I believe my pressures are above max. This is faith based but I believe the numbers more than primer indications.

Primer indications that I always trust: Pierced or blown primers. When you get those your pressures are too high. Period.

Extraction difficulties vary by pistol. I have loads that are hard to extract in my .357 M27 but fall out in my .357 Ruger Blackhawk. I am of the opinion that these loads are too hot in the M27. Without the ability to measure pressure I really don't know what is going on, but consider sticky extraction a 100% positive indication of excessive pressures.

Sticky extraction does not always show up when there are excessive pressures. I made a copy of an article where a pistol shooter had 80K psia loads in his pistol without any extraction issues. His load levels so concerned the magazine editors that they duplicated his loads in pressure equipment. His pressures were extremely high, above proof load pressures for the 30-06 Springfield rifle.

Brass whose primer pockets expand after a couple of reloads. You know your load is too hot when you can seat a primer with your thumb!

I recommend you shoot factory 125's in your pistol and compare the velocities against your reloads. I do this and I keep my reload velocities below factory. This is not 100% perfect as factories have access to powders that I don't and they can get higher velocities at lower pressures, but at least you have a data point to compare.

 

[4895]

I use W 296 for some loads, but have grown more accustomed to H110. I have loaded .357 mag with 19.4 grains of H110 and 125 grain hornady XTP with small pistol and small pistol magnum primers. I have noticed at this 'reduced' load (still within specs from hornady manual) that I have much better accuracy in my GP100 6". I normally shoot 125 grain bullets with 21.0 grains of H110 and have gone as high as 22.0 with no problems, other than being physically 'pushed' back from the recoil, especially in my 4" GP100. I like 296/H110 for the magnum loads and will go with the Hornady manual that clearly goes below the HODGDON/WINCHESTER/OLIN company start load of 21.0 grains. Check the Hornady manual and save a bit of powder. Take care.

 

[ssyoumans]

Lots of good input, here's some more info to digest:

RC & Clark: I have loaded 296 down to 18.5gr with a heavy crimp without any problems/signs. Those loads chrono'd 1371 fps with no signs of pressure. That data was based on Winchester reloading manual #15 which listed a max for 125gr JHP of 18.5gr, 32,500 cup. I know today's data is much higher, hence the 21.0 - 22.0gr that Hodgdon is publishing.

SlamFire1: I have fired Remington Factory 125gr JHP's through my GP100. They chrono'd 1502 fps. So, I am very close to that load, yet, a full .7gr below start and 1.7gr below max. I have also chrono'd some crappy Magtech's. Rated for 1378fps, came in at 1364 fps.

None of these factory or my reloads showed any signs of sticky extraction. The only time I've really seen that was when I was using 14.0gr of Blue Dot, which was 0.5gr under max of 14.5 (at the time, approx 1997). Those stuck pretty good, and chrono'd 1526 fps. After firing 12, I pulled the remaining 38 that I had loaded. Since then, as most people know, Alliant has stated you shouldn't use Blue Dot with 125gr bullets, although I am surprised that Lyman 49 still has a load in there. I did try some at 13.0gr BD for 1443 fps, but I don't use Blue Dot anymore in 357 & 125gr bullets. Too many other powders to choose from.

 

[Clark]

As an example of crimp.
Hodgdon's starting load for 454 Casull is 34 gr H110 250 gr JHP 37 k.c.u.p. max 36 gr 52 kcup.

In a Uberti Cattleman 45 Colt when I shoot 21 gr H110 250 gr uncrimped should be ~15.5 kpsi if the powder would ignite, the bullet can get stuck in the forcing cone. That revolver is then jammed, really jammed.
But if I load 20 gr and roll crimp, should be ~ 13.5 kpsi, I can shoot that all day long and they all work fine.

A large fraction of the guns I see that are damaged are from stuck bullets.
Hodgdon wants nothing to do with you getting a stuck bullet when you don't do a good roll crimp, so the loads they publish and they advise they give is not depending on your ability to roll crimp.

This is kind of like when I design something, and want to meet the requirements of government agencies. If I ask and agency expert what the requirements are, the short answer is that the requirements allow me to do very little. I have to sit through the long complicated answer to find where I can eek out some options.

Hodgdon is giving you the short simple answer.

 

[gamestalker]

I load exclusively with H110 and 296 for all my magnum applications, and can tell you from experience, that those two powders are not meant to be reduced to lower than the published start charge.

Hornady shows a starting charge of 18.8 grs., Nosler 18.6 grs., Sierra 18.6 grs., and Speer 18.3 grs., and Winchester shows 18.5 grs. Hogdon does show the data your referring to, so I don't really think you are too low. In fact, it seems Hogdon is only 1 published data source that starts that high out of 6 sources published. And the maximum charge among those is still lower than the starting charge you are using. Take your charge down to 18.5 grs. and begin your load developement from that point.

Primers are unreliable for reading pressures, how they extract is deffinitely more reliable? If you are experiencing stiff extraction then that would be a more reliable presssure sign. Primers are subject to various causes of flattening, and it's not always high pressures that are at play.

I have also learned over the years which elements of loading can rasie pressures quite a bit. One of these elements is brass length. Make sure your brass is trimmed to below SAAMI max. case length. When the brass is allowed to get longer than this, the pressures are delayed from escaping because the bullet is in the case longer.

Another possible cause can be the crimp not holding onto the bullets good enough to prevent bullets from jumping up in OAL, especially at the operating pressures associated with 296 and H110. This could explain the inconsistent flattening of the primers or other apparent pressure inconsistencies. To find out if this is the cause, load a full cylinder and then check all the remaining cartridges for bullet jump after each round discharged. It is almost impossible to prevent bullet jump if you aren't using a roll crimp with full house 296 loads.

As I stated, I load exclusively with H110 or 296 and don't have pressure problems. But any time we load with a powder that onyl has one purpose which is full house, we must make sure we are doing everything right or the already high operating pressure can go excessive in a heart beat. And since you are using a bullet different than that of the published data, it is advisable to load with a bit lower starting charge, but as per published data only! though.

 

[35 Whelen]

I use W 296 for some loads, but have grown more accustomed to H110.

These powders are one in the same, identical...as in dispensed out of the same hopper, just as HP-38 and W-231 are identical. Check out Hodgdon's on-line data. H110 & W296 data are right on top of each other with identical charges giving identical velocities and pressures.
Years ago I had a Winchester paper loading manual and they warned VEHEMENTLY against REDUCING charges of W296 in their 357 and 44 Mag data. Likewise, Hodgdon's on-line data for the 357 and a 125 gr bullet show a starting charge of 21.0 grs and a max of 22.0 grs.

35W

 

[buck460XVR]

My advice would be to not go below the recommended Start load.
rc

yes, but Hodgdon's start load is over max according to Hornady, and both companies used the same bullet in their recipe. Same goes for Speer's recipe with their 125. I believe both of their max loads are the OP's start load. I don't load 125s, but I do load 158's and the remmie 158s seat deeper than either the Hornady or the Speer 158s and thus I load them a tad lighter. If the same is true for the remmie 125s, then I could see a near max or close to max load exhibiting signs of over pressure in some guns. I know Hodgdon's loads tend to be on the warmer side in my guns. One reason I check more than one reference before I start something new. If they shot well accuracy wise, I wouldn't see a reason to go hotter if I was getting the velocities I wanted. If I was getting sticky extraction I'd back down.


But in the long run, this is still the best advice.........

1. Forget "reading primers" unless you are also an accomplished tea lief or palm reader.
For the rest of us, they both will tell you about the same thing.

2. Follow the published load data, and don't try to second guess the ballistics labs who pressure tested the Start & Max loads.

rc

 

[gamestalker]

Older reloading books and even the most recent "One book, one caliber" I have has some contradicting data with 296 and H110. I know, and most everyone else knows that, H110 and 296 are the same. Even the manufacturer's have confirmed this. But the on going data conflict seems to still be alive and well. I wonder when those two powders will be publsihed as one of the same?

 

[NCsmitty]

My easy answer is stick with 2400

That would be my choice too. I've never cared for H110/W296 in my magnum handguns because it was too finicky. H110 works well in my 410 heavy shotshell loads.

Your 2400 loads and fired cases are much better looking and you have room to safely improve should you choose.


NCsmitty

 

[JRH6856]

FWIW, Quickload shows the load of 20.3gn of 296 under 125gn JHP in a 6" barrel to produce 38,731psi and 1,691fps.

21gn is 44,460
22gn is 54,541.

 

[rcmodel]

I wonder when those two powders will be published as one of the same?

They are right now by Hodgdon, who sells them both.

At least the data is the exact same for both.

Why they still sell two different can labels is beyond me though.

Must be a marketing agreement of some kind.

As far as other published data?

Reloaders will still be looking at old manuals with two sets of data long after I am dead.

rc

 

[cfullgraf]

Why they still sell two different can labels is beyond me though.

I would guess there are some Hodgdon powder freaks and some Winchester powder freaks that still swear the powders are different.

No big deal on the packaging line. Hodgdon would just change the labels in the labeling machine and change the cartons in the cartoner.

 

[ljnowell]

I know this is off topic, but another poster put it first, I like alliant 2400 for many reasons, and this is another of them.

 

[fguffey]

“It can also be that your pressure is so low, the primers are backing out, then the case slams back against the recoil shield, giving the flattened appearance when they are violently re-seated, with full chamber pressure trying to keep them from being re-seated”

And we never want to forget, the primer is unsupported during the big bang so someone needs to understand it is not the sudden stop that flattens the primer, it could be all that pressure building inside the primer before the case makes it’s sudden stop and continues its role as ‘primer supporter’. that is, if time is a factor, if it happens suddenly and all at once, no one knows.

F, Guffey

 

[sugarmaker]

Watch your seating depth, some bullets have longer shanks for a given weight and will seat deeper, this will cause high pressure. Also your gun may have tight throats, which can also raise pressure. I wouldn't be alarmed at those primers but also would not increase the load further.

 

[ssyoumans]

Regarding crimp - it checked out ok. I fired 10 rounds though my SP101 2 1/4" barrel, to test my crimp. Fired 4, then measured the 5th. In both cylinders full the COAL grew from .002" to .003". It never jumped the crimp. So, I think I'm good there.

I got the same looking primers whether it was fired in the SP101 or the GP100, so that reduces the chance it is gun related, and the fact I don't see it with other ammo (the 2400 loads doing about the same velocity with the same bullet). I think, but can't say for sure that this eliminates the "bullet". I suppose I could try with some Sierra 125's that I have and some Montana Golds, but again, issue didn't show up with 2400.

Since I haven't gotten any sticky extraction, I may trying bumping up to 20.6gr and 21.0 gr sometime. As others have mentioned, that may be the best sign of high pressure for a 357 Magnum.

Option 2: it looks like 2400 is nearly matching 296 in velocity. I still have 0.9 to 1.6gr I can increase my 2400 load (MAX 16.9 per Hornady, 17.5 per Alliant, 17.6 per Lyman). So, if looking for full power load, that might be a better option. But, I will say that 296 loads generated a lot less flash and felt different than the 2400 loads (which surprised me, since both are pretty slow pistol powders, I thought they would be more similiar). I liked 296's recoil more than 2400's.

 

[gamestalker]

I still suggest that you take the charge down to what most of the manufacturer's are calling a start charge, to 18.5 gr. with 296 or H110. Everything else your doing sounds just fine. The only reason I'm mentioning it is because you seem a bit aprehensive about your pirmer signs, not that this would positively solve that common effect with full house loads.

 

[ArchAngelCD]

Those primers look just like most of my fired .357 Magnum cases made with W296/H110, especially the Winchester cases. I did notice the 2400 loads were made with Starline brass as opposed to the Winchester cases and W296.

I rarely if ever use a 125gr bullet in the .357 Magnum and mostly use 158gr bullets. I usually stick with the Max published charge of W296 or at least very close to Max. Hodgdon lists a Max of 16.7gr W296 with a 158gr bullet and I have a load I like that uses 16.4gr W296. Unlike some of the suggestions to lower the charge weight I would bump it to 21.0gr with that 125gr bullet.

You are using a Magnum primer, right??

 

[Walkalong]

I agree that the primers are no big deal. If you want to run 125s at close to 1500 FPS, you are going to see some flattening of primers. Perfectly normal. If the case head has not expanded any at all, and the case eject easily, you are fine. I have caused some case heads to expand with primers that look OK when delving in uncharted waters with a caliber with no data, or at least data for the combo I wanted to use. I am not recommending this, just saying.

 

[USSR]

I've never cared for H110/W296 in my magnum handguns because it was too finicky.

+1. Have found all my magnum handgun loads (and .30 Carbine loads) can be easily handled by either 2400 or 4227.

Don

 

[codefour]

I've never cared for H110/W296 in my magnum handguns because it was too finicky.

+2 I never had good luck with H110/W296 either. I had much better luck with 2400. You lose just a tad velocity, but 2400 is much more reliable and consistent.