View Single Post
Old January 31, 2012, 05:24 PM   #6
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 10,195
m&p45acp10+1,

Even that starting load you mention is shooting faster than the long time wadcutter standby 2.7 grains of BE mentioned by PawPaw. 2.9 grains of 231 is about equivalent. The higher velocity loading is fine with a DEWC, but put an HBWC in and fire it from a snub nose or other short barrel, and the skirt may blow out and destabilize it.

It's a funny business originating, as near as I can tell, from Hodgdon's load data. Go to Hodgdon's site and look up the 231 loads they give for 148 grain HBWC over 231 and note both the peak pressure and velocity of the maximum load. This was shot in a 7.71" test barrel according to what you see when you push the Print button at the top of the page. Now switch the chambering to .357 Magnum with its longer case and COL, which should lower the pressure. Look at the smaller starting and maximum loads and note the maximum load pressure and velocity. This was fired from a 10" barrel. Smaller loads for .357 getting higher peak pressure with more powder burning space but producing lower velocity in its longer barrel. Huh?

My first thought was maybe it's the magnum primer in the .357. But, make the same comparison for Hodgdon Universal, a flattened-sphere "flake" that burns at the same rate as 231, and it reverses, with the magnum case needing more powder, as you'd expect. The smaller loads given for Universal in both cartridges, are just about exactly what I'd expect to be right for 231, but the .38 data is still odd. I can't come up with any scenario to explain it that would not have brought similarly odd results to the other powders listed for both cartridges.

I wrote Hodgdon about this, saying it looked to me like their .38 Special and .357 Magnum load recommendations for 231 had been reversed. They took the time to look up the test sheet filed by their ballistic technician, who'd apparently been told to load to specific pressure readings. They said whether it makes abstract sense or not, this is what they got, and it's what they are sticking by. The subtext I infer is this is how the lawyers want it done. I prefer to run the 231 lighter with .38 Special wadcutters for target shooting, to get the old standby 750 fps from my 6" K-frame. 2.9 to 3.0 grains depending on the brass and crimp. It's an oddball case of the chronograph being more useful than the published data.
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Patron Member
Unclenick is offline  
 
Page generated in 0.04834 seconds with 7 queries