32 S&W pressures

[Gunfreak25]

I was comparing pressures/loads in my Lee book for 32 S&W and 32 S&W Long.

32 S&W

-85g round nose
-1.4g Win231 powder
-9500 CUP
-595fps

32 S&W Long

-98g round nose
-2.7g Unique
-9700 CUP
-715fps


What gives? The loads create basically the same pressure yet the 32 long load uses a much heavier bullet and moves over 120fps faster?

[I'll Make Mine]

The longer case with heavier powder load is keeping pressure up all the way to the muzzle, while the lighter load in the smaller case is burning out before the bullet exits -- I'd bet the S&W Long gives a louder report (higher residual pressure).

[Hickory]

It has to do with the amount of powder AND the capacity in which it is contained.
The 2.7 grs of unique, if it were contained in the 32 S&W case would generate more pressure because
the capacity is less then the 32 S&W long.
This is the reason why magnum calibers were developed, to produce higher velocities, and higher pressures.
I am sure that guns manufactured in the 32 S&W long could and will withstand sustained higher pressures.


But back to your question;
What gives? The loads create basically the same pressure yet the 32 long load uses a much heavier bullet and moves over 120fps faster?
You are comparing two different powders that "spike" in their peak pressure in somewhat different times and places in their burn rate.
An example: 11 grs. of unique will in a 44 magnum spike in pressure sooner than 21 grs. of 2400 with the same boolit. Unique will reach its peak pressure as soon as the boolit comes out of the case, whereas a full load of 2400 will reach peak pressure as it travels down the barrel. It will also achieve higher velocity in the process.
In other words, all things being equal, at/or about the same pressure. 2400 powder pushes the boolit for a longer period of time down the barrel creating higher velocity.
And 2400 is better suited for the heavier boolits than unique. Faster burning powders are better suited for light boolit and light loads.

[BCRider]

The big reason is the case volume that was mentioned already. It plays a huge factor in the pressure and muzzle velocity.

A good "apples to apples" comparison that illustrates this is to look at loads for 125gn 9mm and 124gn .38Spl using the same powder and same load. The 9mm will be up around magnum like pressure and the .38Spl will be about 1/3 of the pressure. All due to the case volume.

This is why bullet setback in the short semi auto casings is so hard on the guns and even a proper load can produce KABOOMS! if the bullet is set back far enough due to a poor crimp and recoil forcing it back to where the bullet becomes seated right on the powder.

Back when I was playing around with a "barely legal" 9mm IPSC load I was trying different overall lengths by seating the bullets over about a .030" range in .010 steps. With each .010 deeper seating I was seeing roughly a 30 to 40 fps difference with no other change. That's a good indicator of how sensitive the peak pressure can be due to simply varying the case volume.

[Gunfreak25]

When you ask a question you get an answer around here, thanks for explaining it guys. I have lots of FFg Goex leftover from my old .43 Mauser reloading day's. The original .32 S&W loading was 8 grains of FFFg.

I don't think8 grains of FFg will fit into the small 32 case which only has .40cc internal volume.

I see no problems using longer 32 brass in the gun to get the desired 8 grains of black in there. The only way the long brass will clear is if flush seated wad cutters are used, which should provide the proper amount of powder compression.

I've weighed the smokeless vs black in these guns and this cartridge a hundred times. I just assume stick with black to keep strain on the pistol as low as possible. Plus, I had SO much fun shooting black years ago. I really, really miss reloading!

[pipehand]

Gotta chime in here. You said"The only way the long brass will clear is if flush seated wad cutters are used," which leads me to believe that the cylinder is short, and the gun is chambered in the S&W not the S&W Long. I can't see how the brass will even chamber without a boolit if there is a step in the chamber for the shorter round. If this pistol were chambered for the 32 Short Colt, with its heeled boolit, then you may be able to chamber 32Long Colt brass in the bored through, non-stepped chamber. Just sayin'. Good luck.

[Gunfreak25]

The pistol is chambered for 32 S&W, not 32 long. The reason I said 32 long brass might work is many of the antique revolvers had bored straight through cylinders which cut manufacturing costs. I'm picking it up tomorrow and will know for sure. It could very well have an internal step.

[NoZombies]

I've got a revolver in .32 long with a bored through cylinder. I've been contemplating loading up .32 shot cartridges for it using .327 brass...

[Terryrm1-03]

So at what cup are these lil pistols rated for? Anyone have an idea?
thanks Terry

[Gunfreak25]

Original loading was 9000 cup, max loaded listed in the Lee box is 10000cup. I wouldn't go much more than that, the cylinders are strong enough but the break top design is not noted for strength.