Just for reference

I went to the range last week with fellow 2A member scorpio.
He had a beautiful SW 625 with 4"bbl and shooting some Fed RTP white box ammo (Range-Target-Practice)
I had not shot any factory ammo in a long time so I was curious what they put in their econo-ammo nowadays.

Here is what I found:

45 acp-230 gr Federal RTP lot #Q20M229
Headstamp=Federal 45 Auto
OAL= 1.266 "
Mouth dia=0.470"
Bullet=conventional Full Metal Jacket with NO sealer
Bullet weight=231.7 gr.
Bullet dia=0.4505"
Propellant=5.0 gr. of fine grain flakes
Velocity from the SW 625 4"bbl=837 fps with an SD of 7 fps
Velocity from my 5.5" bar-sto bbl was 857 fps and SD of 8 fps

See pictures-
Note the similar appearance of the powder when compared to Bullseye

Thanks for doing this. I find your deconstruction threads interesting.

Thanks for doing this. I find your deconstruction threads interesting.

....
Thanks
Next up is a round of 45acp from the era of Bonnie and Clyde.

Do you use a camera attached to a microscope to take a picture of the powder?

Do you use a camera attached to a microscope to take a picture of the powder?

....
It's a fancy toy electronic microscope.
It can go up to 200x

Science!
https://www.amazon.com/Mattel-P510002-Digital-Blue-Microscope/dp/B000059TF3

Science!
https://www.amazon.com/Mattel-P510002-Digital-Blue-Microscope/dp/B000059TF3

...
Yes, that is the microscope.
It is old and the software driver just barely works with Windows XP.
I wouldn't even attempt to load it on win 10

Under velocity section:
Velocity from the SW 625 4"bbl=837 fps with an SD of 7 fps
Velocity from my 5.5" bar-sto bbl was 857 fps and SD of 8 fps

What is SD?

Under velocity section:
Velocity from the SW 625 4"bbl=837 fps with an SD of 7 fps
Velocity from my 5.5" bar-sto bbl was 857 fps and SD of 8 fps

What is SD?

standard deviation
measures how consistent the results are
lower is better

standard deviation
measures how consistent the results are
lower is better

That's pretty good numbers for cheepo ammo

standard deviation
measures how consistent the results are
lower is better

....
For geeky electrical and electronics engineers, SD is the equivalent of RMS voltage of a sine wave.

In practical use, it is the range where 70.7% of the shots fall.
In the case of the revolver, the reading was 837 /7
So 70% of the shots fell between 830 and 841.

Just for reference

I went to the range last week with fellow 2A member scorpio.
He had a beautiful SW 625 with 4"bbl and shooting some Fed RTP white box ammo (Range-Target-Practice)
I had not shot any factory ammo in a long time so I was curious what they put in their econo-ammo nowadays.

Here is what I found:

45 acp-230 gr Federal RTP lot #Q20M229
Headstamp=Federal 45 Auto
OAL= 1.266 "
Mouth dia=0.470"
Bullet=conventional Full Metal Jacket with NO sealer
Bullet weight=231.7 gr.
Bullet dia=0.4505"
Propellant=5.0 gr. of fine grain flakes
Velocity from the SW 625 4"bbl=837 fps with an SD of 7 fps
Velocity from my 5.5" bar-sto bbl was 857 fps and SD of 8 fps

See pictures-
Note the similar appearance of the powder when compared to Bullseye

What's causing the faster speed. Twist,  5" barrel or is the speed difference insignificant to postulate. I'll look for a different  45 for you to test. I think I have a veriety. 

Can deconstruction be used to reverse engineer.

Can deconstruction be used to reverse engineer.

It may be possible if you can identify the powder and it is still manufactured today? Maybe a chemical analysis of the powder? The problem is some of the old powders used in military cartridges is not being made or copied.

Can deconstruction be used to reverse engineer?

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In most cases, no.

In this case, the powder sure looks like alliant bullseye powder.
The amount is consistent with bullseye too.
The bullet is of conventional design.
So yeah I can duplicate it. But this generic box ammo is nothing to get excited about.
Guys have been replicating 45ball for decades.

Probability curve for Standard Deviation. The percentage relates to the area under the curve with the median being the average.

There's 2 different methods of calculating SD.
That Bell curve is one of them. Not sure which.
I think rms is like the other one.
The difference is something to do with the mean value.

What's causing the faster speed. Twist,  5" barrel or is the speed difference insignificant to postulate. I'll look for a different  45 for you to test. I think I have a veriety. 

Probably a combination of the extra barrel length and the small loss of pressure from the cylinder gap on the revolver.

5 grns of bullseye would be a pretty warm load with 230grn ball

5 grns of bullseye would be a pretty warm load with 230grn ball

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Yep, very similar to military ball