Pressuretrace II Testing and Historical Data Collecting For The 44-40

[Bryan Austin]

From my dedicated research and testing over the past ten years, I finally came up with a few simplified cross reference charts regarding pressures from historical data, testing data and modern data. I am by no means finished but thought I would share what I have so far. As we all know there is no magic formula to convert cup to psi and psi back to cup. However, we can do a few things with at least a few low pressure cartridges to give us a good idea of what the difference would be in a respectable range.

Using data from a 1917 dated document from WRA's Carriage Engineering Office(earliest I can find), load data from early smokeless powder cans, load data from 1930's handloading manuals, load data from modern handloading manuals, test results from using the Pressuretrace II equipment/software....I came up with the following charts.

Hopefully I can perform the proposed tests noted in the next few weeks.

(charts subject to edits without notice here)

WRA Cartridge Engineering Office Data
Sharpe's 1937 Handloading Data
CUP/PSI Cross Reference Chart
Pressure Time-Line Chart
Armature Test Results
Detailed data added to the 44-40 website here

 

[RegionRat]

Have you ever put a strain gage on one of the black powder revolvers?

Where is the gage placed, the cylinder or barrel?

I was curious how the pressure of an identical load looked between a rifle versus with the cylinder gap?

I bookmarked your web site and will dig through that when I have downtime. Thanks for sharing the work.

 

[Bryan Austin]

Have you ever put a strain gage on one of the black powder revolvers?

Where is the gage placed, the cylinder or barrel?

I was curious how the pressure of an identical load looked between a rifle versus with the cylinder gap?

I bookmarked your web site and will dig through that when I have downtime. Thanks for sharing the work.

The strain gauge is only applied to chamber cut round barrels

 

[RegionRat]

The strain gauge is only applied to chamber cut round barrels

I have put strain gages on many complex shapes, but then the burden of converting micro strain to pressure is on me.
The only reason I asked the OP, is I dread ruining the finish on a revolver to place the gage on the bbl or the cylinder, and I only have 44 in both revolver and rifle.
It is that gas leak that changes the dynamics where the revolver bullet jumps to the forcing cone during that critical gust of pressure that has me curious.

 

[dellet]

Have you ever put a strain gage on one of the black powder revolvers?

Where is the gage placed, the cylinder or barrel?

I was curious how the pressure of an identical load looked between a rifle versus with the cylinder gap?

I bookmarked your web site and will dig through that when I have downtime. Thanks for sharing the work.

I don’t know if this helps, but it’s in the right direction.
If you have not looked, SAAMI has velocity data for test cartridges. For pistol and revolvers there are two columns for what is considered “revolver cartridges”. The test barrels are either vented or non vented. The vented barrel is intended to simulate the gap in a revolver. Velocities are listed for both vented and none.

When you look at the drawings of the test barrels, the only difference is the vent. The test port location would be in the cylinder.

A test barrel like this should give you the results you are looking for and should be easy enough to duplicate by a decent gunsmith. Basically porting a barrel where the cylinder gap would be.

The information is probably recorded somewhere with SAAMI, when they did the velocity tests,but I have never been able to find it. Maybe someone associated with SAAMI could help?

Been down the road that far and stalled, maybe it can help you take it farther.

 

[RegionRat]

Thanks @dellet , one of these days, I'll just have to grab an extra cylinder for a Ruger 44 and see what happens. I don't want to ugly one up with the bonding and the challenge of keeping the profile under the strap.

 

[Bryan Austin]

Strain Gauge Location
RSI notes the following:

Note: If a barrel is not cylindrical at the chamber (where the gage is glued) the system MUST be calibrated against a load of known pressure. This is particularly true of double barrel shotguns with a strong flare near the locking mechanism, octagonal barrels, etc.

The trick is a "known" pressure. Since 44-40 handloads and factory loads my not be published in exact known pressures, this can get tricky.

The backstrap on a revolver will prevent it's use since there is no room for the strain gauge to pass through. However, on Colt's BP revolvers.......there is really no set "control" or known pressure to use. A cartridge case can absorb 7% to 13% of the chamber pressures according to RSI. The end result would simply be relying on more guess work than less guess work. Also, there is no way to add the proper data to be used on a revolver cylinder. Check here: Page 11

Known Pressure
Buffalo Bore hints that their 44-40 "Heavy" is loaded with a .428" lead bullet because using a jacketed bullet will exceed SAAMI MAP pressures. Thus I use 11,300psi with their loads as my "control" or "known" pressure.

Cross Reference
If Buffalo Bore has an 11,300psi result and Winchester has only a 9,500psi result, if the Winchester result should be 11,000psi...then the Buffalo Bore loads really exceed SAAMI Map pressures. What ever pressure correction is added to the Winchester test has to be added to the Buffalo Bore test.

44-40 Bullets
Don't forget the 44-40 is technically .427" and Winchester's JSP is only, and has always been .4255". Most JSP used now are .429"/.430" 44 Special and 44 Magnum bullets, not 44-40 bullets.

Strain Gauge Removal
I removed the first strain gauge from my testing barrel and not a scratch on the bluing....using RSI's supplied glue.

Rifle Cartridge vs Pistol Cartridge
Also note that the 44-40 is and has always been a rifle cartridge. Winchester only listed it as a pistol cartridge, along with the 38-40, because it was also used in the revolver and was so listed as such for sales purposes only. This was discussed in the 1940's when the explanation of the separate categories was explained. SAAMI also listed the 44-40 as a rifle cartridge in the rifle section, not the pistol section. Thus there is no vented information for the 44-40.


Also note the different names given to the 44WCF for Winchester and 44 Remington for Remington's 44-40. There was a difference, Winchester being 200gr while Remington was 217gr....both of which settled for 200gr eventually for both lead and JSP. Winchester also used the 44-40 name and first seen on ammo boxes in 1903 on the 44-40 High Velocity cartridges.