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With the work at the reloading press complete, all that was left was that trip to the range. Then, if things looked favorable, another batch of cartridges would be made with a smaller spread of powder weight steps using the same Hornady SX bullets. After that, a load constructed using FMJ bullets (using a reduced starting load and working back up to the desired powder charge) would come.....assuming I got good results at the range.
At the range, I put up a simple target comprised of several small squares (about
1"x1") of painter's tape to use for point of aim. I used my Saiga .223
rifle with a 16" barrel. It has iron sights.....typical AK-47 front and
rear. I relied on my Pact MKIV-XP chronograph
to record the velocity numbers. The skyscreens were positioned
approximately 10' from the muzzle.
|String||Grains||Std Dev (FPS)||Avg Velocity (FPS)||Change (FPS)||Spread @ 25 yds|
The photo and chart show the results obtained at the range. I was very pleased with the overall results. I realize that measuring group size out to .001" isn't practical, but I was used my dial micrometer to get a measurement on the spread.
Note the change in velocity for the first 4 strings. Now look at the increase for the 5th string. As with the previous steps, a .5 grain powder increase but this time only a 16 feet per second increase in velocity. At the same time, the spread on target increased by more than 300%. In my opinion, there is no reason to do any subsequent testing above 23.5 grains. When I increase powder and see virtually no increase in velocity, I stop.
While I was shooing, I retrieved the brass cases after each string. Each was checked for any signs of excessive pressure. As long as the chrono readings were looking good along with the brass, I advanced to the next powder charge after letting the Saiga's barrel cool down a bit.
String #3 certainly deserves another hard look too. There is a distinct possibility that low/right shot was a flyer caused by yours truly. I can't say for sure. So....the sweet spot might be anywhere between/around 22.5 to 23.0 grains for this particular configuration (powder, primer, bullet, and firearm). I will load another batch with a narrower focus on the promising powder range.
There are other methods by which to arrive at a good ammo/firearm combination and you are encouraged to seek them out and try them. As I said, this range session was intended to find a reasonable velocity load that provides good accuracy and reliable functioning in my Saiga .223 rifle. Based on this first set of results, I'll be doing another trip to the range to see if I can get the group a bit better.