Revolver versus Pistol: same bullet, powder charge and seating depth

T

TheGuyOfSouthamerica

Moderator
Hi ya'all

I want to compare the same bullet, seating depth and powder charge using an Pietta SAA 357 mag 5.5“ revolver and the Taurus PT 92 AFS 5“ in 9 mm Luger.
The powder volumen space of the 38 spl case is about 7.5 grains water and the 9mm Luger has 6.7 grains (6.6 grains in my last measure) of water of volumen so that means they are seated roughly the same depth. According to an poster here the 9mm Luger should have about 7.5 grains of water weigth able to enter were the powder space is to be within pressure standards of max 35000 psi.
I assume the same thing for the 38 spl shot out of an 357 magnum revolver.

Data for both cases and calibers
Bullet: Lee lead cast 124 grain Truncated Cone .356“ diameter
Powder: O***a scavenged 3.9 grains
Case: 38 spl Nagant style deep seated
9x19 seated to 1.040“ OAL

The 38 spl loaded like above and it gave me 1047 fps which translates to 302 ft-lbs.
My theory is that the 9x19 will have similar speed and energy since it is loaded almost identical.

Once I have the pistol on hand I will update this experiment.
 
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BBTI compares Barrel length of the SAME caliber.

I can nowhere find th Webpage compares one same powder Charge applied to 38 spl and 9x19 with the same bullet.

Show me what you mean and were I can find that info.
 
Hello again TGOSa, I would think if internal case volume is similar, the same bullet, seating depth, and powder charge would produce similar pressure, velocity and energy. The 9MM has so little internal volume though that small changes, like a small difference in internal case volume between the 9MM case and your 38 Spcl. case, may produce greater differences in pressure and velocity than might be anticipated. And of course, if the deep seated 38 Spcl. is tested in your revolver, and the 9MM tested in a semi-auto pistol, another variable is introduced. I admire your efforts.
 
The idea of this Experiment is to see if both pressures are about the same. Since I do not have the Beretta 92 at Hand yet, I try with this to extrapolate the behaviour of the 9x19 in order to not blow up the new gun.

The Glock type pistols have a thick square block around the firing chamber where the Taurus PT92/Beretta 92 only has a thin Barrel tube (no thick steel surrounding where the round fires).
So I figure that may be a weak Point.

Due to the chambering Problem of lead bullets in 9x19 they seat deep and therefore reducing the powder compartment of the case from normal 7.5 grain of water to 6.6 grain of water (or OAL 1.160" to 1.040" OAL). The 38 spl seated Nagant style Wadcutter has 7.5 grain of water weight Fitting in it's powder space but the 9x19 not.

Therefore my Experiment with the .356" Diameter 9mm bullet (124 grain TC) in the 38 spl case to try to extrapolate some velocity and therefore pressure.
 
I'm lost! What difference does it make? My carry gun's are both semi auto's in 9mm. My largest fun gun is a DA Revolver in 38 spec. In the 9mm I only load 124gr cast bullet's. In the 38 only 150gr HP cast bullet's. I think the heaviest bullet for the 9mm is 147grs. I'm not sure about the 38spec but I know it'll run bullet's up to 158grs.
 
Don Fischer,

I don't understand your question.

However the bullets of the 9x19 and 38 spl are essetially the same Diameter. Case should be similar as well if seated the same depth leaving similar powder space Volumen. If the bullets are same weight I figure can extrapolate some similarities.
 
I think I would load the same bullets in both cartridges, use similar powder charges and run them over my chrony. I ave a mold for bullets I use in my 9mms, 38 Specials, and 357 Magnum; 125 gr LRNFP. But, with such different cartridges it prolly wouldn't tell much. Does anyone you know have "Quick Load" that can figger the ballistics for you?
 
Over here I am most likely the "lone star wolf" reloader within 500 Kilometers.

No one is reloading I know of. No way Quickload is around.

If you load the 125 grain then you can load an 9x19 and 38 spl with that let's say 3.9 grain of VV N330 powder or similar. Just make sure the powder space Volumen of the 38 spl is Nagant style deep seated below flush (shot only in an 357 mag Revolver).

OAL of 9x19 is 1.040" and 38 spl has similar empty powder airspace.
 
It is a good thing you are using a 357 magnum hand gun for your test because 33000 cup is about twice the pressure that a 38 uses.
How are you going to measure the pressures in the two guns?
Measuring the velocity is easy with a chronograph but most people have no way to measure chamber pressure.

Your test is slipping toward the far side of safety.
 
why is it unsafe?

To be safe I conduct that.

I understand the pressure is a function of the velocity. So more velocity more pressure.

First, once I have the PT 92, I start with loads of 3.3 grain, then 3.5, then 3.8 then 3.9 grain of O***a type (VV N330) powder. See when the slide loads reliably.
If the pistol loads reliable that is my safe Point. From there I will see how much energy the round has and see if the energy is enough for my use. The energy I would be expecting to be between 300 ft-lbs to 350 ft-lbs.
The 3.3 grain worked just fine in an Glock type pistol (just above the Point or reloading reliable with it's 17 lbs spring).
 
TheGuyOfSouthamerica why is it unsafe?

To be safe I conduct that.

I understand the pressure is a function of the velocity. So more velocity more pressure.
Click to expand...

That is your first mistake. Velocity has no correlation to pressure. As a matter of fact higher pressure can cause lower velocity and just after that your gun can explode. I can load bullseye to the same pressure I get with H110 in a 357 magnum but the velocity will be a lot lower. If I tried to increase the charge of bullseye to get the same velocity as I get with H110 it would likely blow the gun up before it got there.

The kind of containment, its volume, its shape, amount and rate of the chamber expansion and the amount of leakage can all affect pressures.

I didn't say that this experiment is unsafe. What I said was that your experiments are getting closer to the unsafe area. Because we can't measure pressures adequately we have manuals filled with data that are tested for pressures as well as consistent ignition. You are just starting to learn about this subject and there can be a very thin line between a good load and a bomb.
 
I will consider the warning.
So i start low with 3.3 grain which is a proven 9x19 round at the 1.040“ seating depth and work my way up.

Do you know any 9mm Luger data for 1.040“ seating depth for an lead 124 grain bullet and about VV N330 powder?
 
Hello again TGOSA, My second edition VihtaVuori reloading manual has some data that might be of help. It lists a lead 124 grain 9MM semi-wadcutter seated to 1.142" with a starting load of 4.3 grains of N330 (1113 fps) and a max load of 4.9 grains (1183 fps).

It also lists data for a Hornady FMJ/FP seated to the same 1.142" overall. Listed starting load with the jacketed bullet is 4.7 grains of N330 (1084 fps) with a max load of 5.3 grains (1192 fps). Both of these were in a 4" test barrel and indicate a starting load pressure of 24,900 psi and max load pressure of 33,000 psi. Hope this may be of help.
 
Thanks rock185,

Is there None load listed for an OAL of 1.040"?

Or the lowest OAL data would be an reference Point as well.

I have realised my 9x19 are of about the power Levels of an 9mm Glisenti (which is an 30% weaker 9mm; all things otherwise equal).
 
starting load of 4.3 grains of N330 (1113 fps) and a max load of 4.9 grains (1183 fps).
Click to expand...

This somehow does not make much sense. 4.3 grains gives 1113 fps and 4.9 grains gives 1183 fps.
Just a slight difference in velocity between min and max load but a big difference in powder charges (0.6 grain).

What I have found is each 0.1 grain of VV N330 gives an additional 20 fps in velocity (considering a linear equation). So the max load should be about 0.6 x 20 fps = 120 fps quicker (1233 fps). Seems the law of deminishing Returns kick in in this case.
 
the guyfromsouthamerica said:
According to an poster here the 9mm Luger should have about 7.5 grains of water weigth able to enter were the powder space is to be within pressure standards of max 35000 psi.
Click to expand...

It is a VERY poor idea to use unsubstantiated data posted on the internet when you are making something that will explode literally inches in front of your face. There are many variables and it only takes a small variance in any one of them to make the explosion too powerful to be contained in the barrel. When that happens your pistol becomes a bomb right in front of your eyes.

the guyfromsouthamerica said:
This somehow does not make much sense. 4.3 grains gives 1113 fps and 4.9 grains gives 1183 fps.
Just a slight difference in velocity between min and max load but a big difference in powder charges (0.6 grain).
Click to expand...

It does make sense. Velocity, Pressure and Powder Weight are NOT linearly related. Get your data from a manufacturer that has tested the components you are using if you don't want to blow up your gun
 
This 7.5 grains of Water Content weight for the powder compartment actually makes sense.
The info stems from Unclenick who seems to be an engineer of some sort and actually that is a method to quantify the Volumen by weight.

Think a Little bit about it. It makes sense. I just hope my tap rain cisterne water has the Standard weight of an american tap water.
 
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Isn't comparing the 38 Special and 9mm Parabellum (Luger) like comparing an apple and an orange?

For the .357 Magnum the barrel has a groove diameter of .355" (9.05mm) and the bore diameter of .346" (8.79mm). A .357 Magnum bullet has a diameter of .3590 -0.003" Lead and .358 -0.003" Jacketed.

The 9mm Parabellum (9mm Luger) barrel has a groove diameter of .355" (9.02mm) and a bore diameter of .346" (8.79mm). A 9mm bullet has a diameter of 0.3555 -0.003" with no differential between lead and jacketed.

The two cartridges use a different diameter bullet in normal operations and different cases. I guess I do not see what is to be gained using an incorrect bullet in either case?

I want to compare the same bullet, seating depth and powder charge using an Pietta SAA 357 mag 5.5“ revolver and the Taurus PT 92 AFS 5“ in 9 mm Luger.
Click to expand...

Why?

Ron
 
reloadron

...since I bought an new Taurus PT 92 9mm Para pistol and wanted to reload already some ammo for it [before I have the pistol on Hand] and have an General idea, same bullet same powder weight of eighter 38 spl case and 9x19 case , of the velocity and pressure.

Extrapolating 9mm Luger velocities from an 38 spl case with above consitions.

In order to NOT blow up the 9x19 pistol with OAL of 1.040" and 3.9 grain of VV N330 Charge. Which gives in an 38 spl case 1047 fps and 302 ft-lbs 9mm Glisenti type power Levels.
Don't worry: I will work the load up from 3.3 grain VV N330 to 3.9 grain and see when the pistol cycles reliably.
 
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