WC872 in 223
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.
Once again, just as with 308, there is no published data for 872 in 223.
Today I loaded and tested some 223 using WC872 surplus powder. Once-fired LC brass, CCI #41 primers, Hornady 75 gr HPBT. This test started with WC872 at 100% case capacity, not compressed. Then each successive step was one less grain 872 and one additional grain WC844 (at the primer). I used my scale for the 844 portions, and Lee PPM for the 872, measured by volume using the AA8700 factor I found to be useable. I loaded ten of these steps until I was at 38% 844 underneath 62% 872. I only loaded one of each step, and two of straight 872. My intention was to start with the straight 872, examine each fired case carefully, and abort the test at the first clear sign of excess pressure. I was looking for where a pressure spike would happen. I do know what excess pressure looks like in this bullet and cartridge, and I had some of these fired cases (flattened and micro perforated) for comparison, and also 10 more live of that same load.
So, I fired all 10, slowly and examining the case each time. Step #9 flattened the primer but #10 did not. I think #9 may have been loader error (might have had a little more powder, I caught my self muffing a couple I had to dump out and remeasure). I also grabbed the barrel after each shot, because my 844 loads heat the barrel more quickly than I like. Heat was not a problem with these loads.
This test appears to indicate that up to 25% 844, underneath 872 is safe. Steps 7-10 will be repeated, at 1/2 grain increments to recreate or disprove the #9 issue.
My next question/test will be mixing, rather than stacking these two powders, and see how/if that behaves differently, and if I can find an accurate load that uses mostly 872 and burns cooler than 844.
I should add that these tests (308 & 223) were all using Savage bolt action rifles and I do NOT think 872 will have application in gas operated guns, due to the slow burning speed granules of partially burned powder could get into the gas system. Also gas systems work best within a specific pressure band at the gas port.
Last edited by Marco Califo; October 27, 2012 at 07:45 AM.