357 H&H Cast Bullet Accuracy

My best cast deer hunting load for my Winchester Classic in .375 H&H was developed by first using Sierra game king bullets and H870 powder: 72 grains H870, CCI 200 primers, and the Sierra bullet seated to almost touch the rifling.  I was running each round over my chrony, and put 10 shots at 100 meters from the bench into 1.276 inches averaging just over 1925 fps.  There were two called fliers out of that group (pushed group to 1.79") that were each a litte over 75 fps slower than average.  Temperature was 98 degrees with almost no wind.

I switched to my 335 grain NEI (old NEI) spitzer w/hornady GC cast of WW plus lino and HT, sized .377 and lubed with M&N, seated to just touch the rifling.  Average velocity was just barely higher than for Sierras.  These were shot one week later than the Sierra loads.  Temperature was 92 degrees with 5 mph wind, again at 100 meters.  One flier out of the group to the left (because I missed a wind gust:X), and  some vertical stringing.  A ten shot group w/o the flier was 1.66 inchs, but only 6/10s inch wide.  I attribute the  vertical stringing to the lack of crimp with such a slow powder.  The powder is not compressed, but fills to base of bullet.

For hunting I cast a softnose bullet using the two step method of a pure lead round ball in a Lyman dipper floating on the melt.  Using a hot mold quickly dipper pour the pure lead, then place under the spout and fill with the above alloy.  Size and GC that day, then HT, then lube.  Accuracy will go down slightly, but still under 2 inchs.  That bullet acts like a Nosler Partition and will usually drop a deer in its tracks.

PS  Don't get in a hurry and mistakenly take hunting the loads without the softnose:  those spitzer hard cast bullets will zip right on through the ribs and lungs like military FMJs and the deer will run into the next county with a very poor blood trail.  (stupidly been there and done that)