Date: 24 Mar 94  19:33:34
From: Ed Harris
To:   All
Subj: .32 H&R Mag. +P+ Test Data

The machine "loading limit"  for the .32 H&R Magnum cartridge is 20,000 
p.s.i., but handloaders often try to get higher velocities than factory 
ammunition in strong guns such as the Ruger SP101 and Single-Six.

The problem in attempting to do this is that no pressure tested data is  
available to approximate ".357 Magnum" equivalent pressures which are known to 
be within the design limit of the Ruger revolvers.  I state here for the 
record that Sturm, Ruger and Company does not condone the use of reloaded or 
handloaded ammunition, and these loads are not approved by them or anybody 
else.

I worked up these loads in my own Ruger Single-Six revolver.  The 85-gr. loads 
work quite well and extract easily, but the 100-gr. loads, while they worked 
OK in an SP101 having roller burnished chambers, gave sticky extraction in the 
Single Six.  I felt it wouild be useful to know what the difference in 
pressure was between loads which extracted easily and those most handloaders 
would agree were crowding the "envelope."  The relative difference is about 
7-10,000 psi.  Loads in the 30,000 psi range worked fine in both revolvers, 
but those approaching 40,000 gave problems in the Single Six.

These pressure data were obtained using an Oehler System 82 and .32 H&R Magnum 
SAAMI dimensioned pressure/velocity test barrel.  All loads were assembled in 
new factory primed Federal cases.  All P & V data are corrected to calibration 
test firings of SAAMI Reference ammunition in accordance with standard 
industry practice.
        
100-gr. Hornady XTP, 4.5 grs. SR-7625   
Mean            1180 f.p.s.,    37,846 psi      - REDUCE 5%
Range           32              4785
Sd              9               1524

85 Hornady XTP, 5.0 grs. W231
Mean            1317 f.p.s.     32,851 psi      - OK
Range           57              6445
Sd              17              1925

85 Hornady XTP, 4.5 grs. SR-7625
Mean            1216 f.p.s.     27,882 psi      - OK
Range           85              9692
Sd              26              3006

100 Hornady XTP, 5.0 grs. W231
Mean            1264 f.p.s.     40,202 psi      - REDUCE 5%
Range           32              6006
Sd              12              1999


The above 85-gr. loads should be safe in the Ruger SP101 and Single Six as 
listed.  Prudent reloading practice demands you should reduce the load 5% and 
work up cautiously to these charges, to provide a safety margin for any 
variations in guns or components.

In my opinion the same charges with the 100-gr. bullets are excessive, as 
evidenced by sticky extraction, and must be reduced a minimum of 5 percent, 
and that charge reduction considered maximum.  The charge listed should be 
reduced by 10% for initial trials in your revolver.

The above data are provided for the information of experienced handloaders 
only who adapt or use the above at their own risk. 



In Home Mix We Trust, Regards, Ed
 

--- msged 2.05
 * Origin: Home of Ed's Red (1:109/120.3006)

