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Rule3 · 07-13-2018, 08:30 PM

Here is a cut and past from another thread, it was dealing with short barrel 357 Mags, not 38 +P but the basic principals are the same, just a little less powder for 38 special.(but 38 special can and is loaded to near 357 Mag loads less around 10%
I didn't have enough HS6 to use, plus I find no real reason to use it.

Question:
Do slower powders produce higher velocities in a 357 Mag Short Barrel revolver?

Recoil, blast and flash are not part of this.

Research:
Most reloading data manuals and online powder companies show slower powders do produce higher velocities in tests using longer barrels or test barrels. Hornady may be an exception as their data is usually more "conservative" in all their loads than say Lyman or Speer.There is data going back to Speer #8 that shows higher velocities in short barrels also, Several of the test powders are no longer available. Most all Magnum powders are of the slower burning type. This is also shown in other high pressure calibers,
The adage of "powders that produce the highest velocity in long barrels will also do so in short barrels" Is a pretty well accepted statement. There are of course some who dispute this.
That brings up the fluff of "authoritative" learning vs Observation or Scientific approach? Internet myth. old wives tales? Maybe it needs to be on YouTube to considered "proof"??

What/who is the authority on reload data? It is the powder companies and the reloading manuals, that have done the actual testing.
This is where reloaders/handloaders obtain information!

Sure individuals can do their own tests, but if the data source is not revealed than how can it be compared? If a max load of two powders is compared and the actual data of one of the powders is below the listed max then yes the data will be skewed. That said, one statement on anecdotal evidence doe not prove anything,

As with ALL TESTS results will vary, sometimes a lot.!!
If the data from the current Speer manual/rather than Lyman was used than all these results would be different!

Hypothesis:

Based on reloading manual data and powder companies data, Slower burning powders should produce higher velocities in a short barrel.

This test is based on the information below and is "only a test" of these loads, bullet, firearm and test conditions.
Factors such as specific bullet friction, cylinder gap, exact bore dimensions and other minutia are present but not considered,

Test:

8/12/2016

12 noon
Temp 90F, Humidity 80% (HOT!)
Altitude 4-5' above Sea Level in the Swamp
Moon Phase "Waning Gibbous 69%"
Solar- No abnormal flares reported

Chronograph, Competition Electronics Pro Chrono Digital
10' from bench

Firearm = Ruger SP101, 2.35" Bbl
Brass= Remington .Trimmed to length
Bullet= Speer 125 TMJ FN
COL=1.577, Firm roll crimp at cannelure
Primer=CCI , 550 SPM (all loads)
All powder drops were hand weighed/checked on a calibrated Dillon Eliminator beam scale
Data obtained from Lyman #49 page 357 (yes 357)

Start loads used. Data for HP 38 from Hodgdon

Test Data:

Bullseye 6.5 gr

Avg=1024fps
H-=1031
L=1020
ES=11
SD=5
-----------------
HP 38, 7.3gr

Avg=971 fps
H=1002
L=938
ES=64
SD=32
---------------------
Unique, 7.0gr

Avg=897fps
H=956
L=859
ES=97
SD=38
------------------------------
Power Pistol, 9.0gr

Avg=1066
H=1102
L=1082
ES=74
SD=27
-------------------
2400, 13.0 gr

Avg=1028
H=1043
L=1004
ES=39
SD=21
-----------------------------
H110, 21.0gr

Avg=1200 fps
H=1240
L=1172
ES=68
SD=28

------------------------------

Added Data for Max loads of Unique and H110/ All else remains the same

Unique,9.7 gr

Avg=1276
H=1297
L=1235
ES=62
SD=24

H110 Compressed, 22.0gr

Avg=1268
H=1299
L=1249
ES=50
SD=19

Strange the high and the low are higher than Unique but the avg is lower? Spikes? Not enough of a sample size?

Conclusion/Review:

In this test, with this gun, on this day. The start load of H110 produced the highest velocity of all powders tested.

That said, based on "experience" and many, many tests of other powders, calibers, some of the powders do not perform well at the lower levels, Many only begin to work well at mid range towards maximum. H110 powder has very little leeway between low and high.

Of course when the charge levels are increased a whole new set of data points will be revealed

A lot of similar testing was done in the past for the 327 Federal Mag in a SW M632 Pro 1-7/8 barrel (not ported)when they first came out. There was almost no data available at that time.
In that cartridge and a 115 gr JHP, H-110 again, produced the highest velocities.

I use a lot of HP38 and Power pistol and find they produce better results at the mid to high range in other calibers.

This test was at the start levels and is not really statistically valid as only 5 shots of each was used. Why? I did not want to use up my expensive JHPs just to collect data,
Also, it is a PITA to adjust the powder measure and weigh each one for 6 different powders, chronographing etc.

I collected, reviewed and enforced "authoritative" statutes, laws, regulations my whole career, doing so in a "hobby' is just not a whole lot of fun.

I also did not test Blue Dot due to Alliants warning, and did not use a SW K frame due to the "internet chatter" of forcing cone erosion with light bullets.

So if someone enjoys testing, collecting data. then that is their enjoyment.

I would rather shoot for accuracy, and do not put much emphasis on if one powder pushes the bullet a tad faster, __________________
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