O.K. What about Max Loads for 357 Magnum using WIN 296/HP 110?

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I have experience with H-110/W-296 in the .357 Magnum. I can't really recommend it for 125 grain bullets as that combination produces a tremendous fireball and is the load combination that also produces the greatest amount of forcing cone erosion and top strap flame cutting. H-110/W-296 does work well with jacketed 158 grain bullets if you are seeking the highest velocity loads.

My max load was 17.0 grains H-110, Winchester 158 grain SJHP bullet, Remington .357 Magnum brass, and CCI 550 primers. It produced an average of 1406 fps and an extreme spread of 19 fps from a Dan Wesson 15-2 with an 8 inch barrel.

Remington factory 158 grain SJHP ammo produced an average of 1442 fps and an extreme spread of 44 fps in the same revolver.
 
I have gone as high as the old Lyman top load of 17.4 grs of 296 with a magnum primer of course, and a 158 gr cast SWC. A very hot load. Chronographed at 1440 fps out of my 4" 27-2. Recoil was sharp and snappy, even from the N frame. Decided I didn't need loads that hot so I would stick to 2400 or Longshot as 296 is not suitable for reduced loads.
 
I have three reloading manuals that show :
357 Magnum
158 gr. Jacketed HP / SP
maximum load of 15.5 grs. H-110 @ 1217 to 1250 fps
all three with magnum primers .

So I would call 15.5 grs H-110 with a 158 gr. JHP / JSP ... Max !
Gary
 
Hodgdon’s load data is from 15.0 to 16.7 for a 158 grain bullet.

For reasons only known to Hodgdon, they use a 10 inch barrel to report handgun velocities with Winchester 296.

1.580" 15.0 1,418 28,600 CUP 16.7 1,591 40,700 CUP

40K or more PSI seems pretty high.

I have best results at 16.0 of W296 with a Hornady 158 grain XTP in my revolvers.
 
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Try 4227
Yes, it leaves a little unburnt powder.
Yes, it falls a half a tickle behind our other magnum powders.
But in 357, this stuff has produced some of the most accurate field ready loads I've ever fired

I have some IMR 4227 and will appreciate being advised of your suggested loads: will check and see if I have any previous loadings with various bullet weights.

Thanks!, and Cheers!
 
I have gone as high as the old Lyman top load of 17.4 grs of 296 with a magnum primer of course, and a 158 gr cast SWC. A very hot load. Chronographed at 1440 fps out of my 4" 27-2. Recoil was sharp and snappy, even from the N frame. Decided I didn't need loads that hot so I would stick to 2400 or Longshot as 296 is not suitable for reduced loads.

I, too, have seen these warnings, but... Looking at the many "published" load data in manuals over the years for H110 & WIN 296 it does tend to make one wonder what the actual potential problem is?

Could it be to discourage the use of these powders in radically reduced loads in, say, 38 Special in an attempt to make less expen$ive alternatives by using less powder?

Jus' askin'?

Cheers!
 
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SAAMI maximum average pressure (MAP) for .357 Magnum is/was 45,000 CUP, using the old-school copper-crusher method of testing.

During the Great Watering Down, SAAMI switched to transducer pressure testing and .357 Magnum MAP is now 35,000 PSI.

SAAMI lists both pressure specs in in most recent centerfire pistol ammunition guide (2022), and claims that both pressure levels show the same velocities.

Having reloaded .357 Magnum for going on 45 years, the current manual loads listed as within 35,000 PSI MAP don't reach nearly the velocities of loads previously listed as within 45,000 CUP MAP. Moreover, as noted, the published propellant charges for the 35,000 PSI loads are significantly lowered from the 45,000 CUP charges.

New reloaders tend to load what's in the current data. Older reloaders, maybe something else.

Keep in mind that the original .357 Magnum guns were designed around the large N frame, and later the Colt I frame. These were/are beefy heavy guns with plenty of steel as both a recoil and heat sink.

Many of the "new" .357 Magnum revolvers are insanely lightweight designs, or updates of older .38 Special designs that have been newly chambered in .357 Magnum. Modern metallurgy is such that the new lighter guns will not "blow up", but when dealing with physics, the pounding that the lightweight guns take from original-spec loads cannot be denied. They will exhibit typical revolver functioning issues - timing, endshake, forcing cone erosion, frame stretch - sooner than later. Hence, the industry desire to reduce .357 Magnum pressure.

The then-new Combat Magnum, later Model 19, is a K-frame gun originally designed as a .38 Special. With then-modern metallurgy, it was chambered in .357 Magnum. The guns did not blow up, but quickly developed a reputation for beating themselves into marginal functioning when shot with a steady diet of old-school 45,000 CUP magnum loads. An example of misunderstanding of the original purpose of that model: mostly practice with .38 Special, then fire a few magnums every so often to get the feel of them for carry.

The new Colt King Cobra is also an example. This revolver is basically a Police Positive Special sized gun - which was designed in 1907 as a lighweight all-steel .38 Special revolver. With a redesigned strengthened frame and cylinder to withstand the current 35,000 PSI .357 Magnum, Colt introduced it a few years ago as the King Cobra; but the cylinder diameter and basic frame size in unchanged. Old school .357 Magnum 45,000 CUP loads would not be kind to either the revolver or the shooter.

The current ridiculous J-frame Ti .357 Magnum guns, are an example of a marketing pitch made possible as the result of a lowered pressure standard for .357 Magnum.
 
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17 and 17.4. Good to see others making Magnum loads.

Al, would you run your 17.4 load in an L frame?

I don't have an L frame but if I did and wanted top velocity I would. An L frame is supposed to handle any factory .357 Magnum load and some factory loads are pretty hot. According to Brian Pearce any S&W is supposed to have a safety factor of double the pressure limit for the ctg without blowing up. The old CUP limit for the .357 was 45,000 CUP but most loading manuals did not go quite that high. Now it's 35,000 psi which seems to be about the same load data as 42,000 CUP. Winchester says 296 should not be compressed or significantly reduced. Now the top loads listed are about 16+ grs. Hodgdon shows reduced loads for H110? I tried a reduced load of 14.5 grs of 296 with a 158 gr cast SWC in the same 4" 27-2 just to see what happened. An unbelievable poor load. Velocity of 1049 fps with an extreme spread of over 100 fps. 5.6 grs of Bullseye or Titegroup chronos around 1060 fps with extreme spreads of 20 fps or less. Many handloaders shoot reduced loads of "magnum" powders and grossly over estimate the velocities they are getting because of the flash and bang. A chronograph can be a rude reality check for handloaders that don't currently own one.
 
When using the Lyman 358156 bullet ( 2 crimp grooves ) I use 16.0 grs of W296 . It fills the case to the base of the bullet . It gives me excepitonal accuracy , is clean shooting the and the cases falll easy from the cylinder .
It is my favorite load with that combination . Regards Paul
 
I have gone as high as the old Lyman top load of 17.4 grs of 296 with a magnum primer of course, and a 158 gr cast SWC. A very hot load. Chronographed at 1440 fps out of my 4" 27-2. Recoil was sharp and snappy, even from the N frame. Decided I didn't need loads that hot so I would stick to 2400 or Longshot as 296 is not suitable for reduced loads.

I bet (lol).

What lyman data are you referring to for that 158gr cast bullet/17.4gr load?
 
Alwslate, that’s good information. Thank you.

If anyone wants to dive even deeper, google “Paco 357 Magnum Literature”. There is a lot of good information there. I re-read it every so often.

Back in the late ‘80s, I bought a box of Federal 357 High Powder 158 JHP in the red and white box. The last 3 of those wonderful rounds were fired from my pre safety Marlin 1894 in 357. Those Federals were going over 2000 fps from that rifle! Other than Buffalo Bore, I’ll bet no other factory ammo comes close to 2000. No wonder that combo was so effective on deer.
 
Something handloaders should realize is that with 2400 powder and also 296 is that the maximum charges are more a factor of case capacity than charge weight. 15.5 grs of 2400 is about all you can get in a case with a 158 gr bullet. About 17.4 grs of 296 is a case full with a 158 gr bullet. You can't get enough powder in the case to develop excessive pressure in an N frame S&W. Winchester says 296 should not be compressed. Brian Pearce proved that you can't overload the .357 with 296 by loading a higher charge than recommended and chronographing showed that velocities went down by doing so. 296 is a dense small grained ball powder and when compressed into a mass ignition is adversely affected.
 
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