Somchem S335

[Roy Beck]

Good morning everyone,
Has anyone tried Somchem S335 in .458 Win Mag caliber ?
I know it works well in .458 Lott so I am thinking it should work well in .458 Win Mag as well ?
Roy

[Tripodmvr]

Here are two projections calculated in Quick Load with a 24 inch barrel and using S335 and S321. The charges are theoretical, but I have calculated to achieve the half node between Nodes 6 and 7 with a barrel time of 1.371ms. As can be seen, S335 burns quicker and pressure is high to achieve 2060fps with the 500gr bullet.
With S321 and the same barrel time speed is 2100fps and pressure is much lower. If hunting in hot weather the pressure with S335 might cause difficult extraction and therefore S321 would be better in such a situation. Recoil might also be stiffer due to faster pressure peak.

[Treeman]

Roy -Tripodmvr has gone way past old school reloading and is resident expert on more than one site in RSA. The shit he calculates is almost magical.
The way I see it is that the bang from the 335 is much quicker and harder than the 321 bang, the reason being it was designed to get the job done in shorter barrels - burn and achieve velocity in shorter time at the cost of higher pressure.
The 321 burns longer, slower and over the length of the barrel.
Thats one thing, the other thing is the big heavy bullet offers to much resistance in the form of weight to be overcome in regard to acceleration for the 335 fast burn rate and this causes high pressures spike. The 321 burns just enough slower to not spike the pressure trying to get that 500 gr bullet moving.

[Tripodmvr]

Somchem are even more pessimistic regarding S335. They have proper pressure testing, whereas QL is there more or less. QL is a very handy tool to see which propellants will give the best performance.

https://www.somchemreload.com/search?c=8&f=130

[Ds J]

I cannot help with calculations, but I do remember a thing or two from an old timer sharing his  experiences  ...

DO NOT - by any means, or in any way - load a compressed load in the 458 WinMag. It is not whether you might suffer terrible ignition due to caked powder, it is just when it will occur. A family member of mine culled elephants with a 458 WM and he vividly remembers the day a bullet from a reloaded cartridge sat between the eyes of an elephant cow.

DO NOT let the reloaded cartridges get older than three months. Something about angry, big footed game and poor penetration.

The 458WM is a good cartridge, but our local powders do not unlock it's full potential.

[Roy Beck]

Hi guys, thanks very much for this valuable feedback and information. So what then are the most suitable calibers for S335 ?

[Tripodmvr]

Primary would be 308W. Some shooters find luck with it in their 223's. My 223 is much happier with S321.

[Treeman]

Primary would be 308W. Some shooters find luck with it in their 223's. My 223 is much happier with S321.

*************
Same findings on my side

[223]

I cannot help with calculations, but I do remember a thing or two from an old timer sharing his  experiences  ...

DO NOT - by any means, or in any way - load a compressed load in the 458 WinMag. It is not whether you might suffer terrible ignition due to caked powder, it is just when it will occur. A family member of mine culled elephants with a 458 WM and he vividly remembers the day a bullet from a reloaded cartridge sat between the eyes of an elephant cow.

DO NOT let the reloaded cartridges get older than three months. Something about angry, big footed game and poor penetration.

The 458WM is a good cartridge, but our local powders do not unlock it's full potential.

The caking of compressed powder is only an issue with the double-based spherical powders like S321 etc.
On S335, which is a single based extruded powder, compression is not supposed to cause caking.

[Treeman]

I cannot help with calculations, but I do remember a thing or two from an old timer sharing his  experiences  ...

DO NOT - by any means, or in any way - load a compressed load in the 458 WinMag. It is not whether you might suffer terrible ignition due to caked powder, it is just when it will occur. A family member of mine culled elephants with a 458 WM and he vividly remembers the day a bullet from a reloaded cartridge sat between the eyes of an elephant cow.

DO NOT let the reloaded cartridges get older than three months. Something about angry, big footed game and poor penetration.

The 458WM is a good cartridge, but our local powders do not unlock it's full potential.

The caking of compressed powder is only an issue with the double-based spherical powders like S321 etc.
On S335, which is a single based extruded powder, compression is not supposed to cause caking.

********************************
Yes, it is the ball propellants that cake under compression, but appears to only be a real threat under tropical type heat and/or long term storage. The ball propellants in the SOMCHEM range all end in the # "1" -221,321, etc

[Againstthegrains]

I've run the simulation with S321 and S335 on GRT, and they are so much of a muchness. The S335 will give you a slightly better case fill and will reach the same velocity with a grain less of powder. I would probably use S335 as a stick powder it is more temp stable, and burns cooler than a ball powder. Ball powder measures easier, but I don't think that is going to make a difference in a 458.

[Treeman]

I've run the simulation with S321 and S335 on GRT, and they are so much of a muchness. The S335 will give you a slightly better case fill and will reach the same velocity with a grain less of powder. I would probably use S335 as a stick powder it is more temp stable, and burns cooler than a ball powder. Ball powder measures easier, but I don't think that is going to make a difference in a 458.

*************************
Its that heat sensitivity that is worrying in a case as big as a .458 and then the usual part of the world where the .458 is generally used, not known for mild days where there be Buffalo and elephants.

[Tripodmvr]

Somchem values agree with what QL has to say. S321 is the better choice and leaves more leeway with lower pressure to accommodate hotter conditions.

https://www.somchemreload.com/search?c=8&f=130



CASE LENGTH    
CARTRIDGE OVERALL LENGTH    
.458 Winchester Magnum
BARREL
LENGTH    POWDER    CASE    PRIMER    BULLET
grains    COL
mm
   LOAD
TYPE    LOAD
grain    VELOCITY
ft/s    V/C
factor
24"    S321    W/W    CCI 250    400gr SPEER FN    
79.2
   Start    77.3    2 372    30.7
Max    81.3    2 474    30.4
            500gr HORNADY FMJ    
84.3
   Start    67.8    2 044    30.1
Max    71.8    2 083    29.0
   S335    W/W    WW    500gr HORNADY FMJ    
84.4
   Start    67.0    1 886    28.1
Max    70.0    1 999    28.6
   S341    W/W    CCI 250    400gr SPEER FN    
79.4
   Start    77.5    2 031    26.2
Max    81.5    2 126    26.1
            500gr HORNADY FMJ    
85.0
   Start    73.5    1 903    25.9
Max    77.5    2 005    25.9

[Treeman]

Wow ! Oom Drie, would excess case space not be a larger factor issue when pressures start rising ?

[janfred]

I've run the simulation with S321 and S335 on GRT, and they are so much of a muchness. The S335 will give you a slightly better case fill and will reach the same velocity with a grain less of powder. I would probably use S335 as a stick powder it is more temp stable, and burns cooler than a ball powder. Ball powder measures easier, but I don't think that is going to make a difference in a 458.

Actually, the ball powder burns slightly cooler than stick.

To muddy the waters a bit, S341 and S335 is around equally as stable. I suspect that S321 would be similar.