There are many fine articles on the web that discuss this load combination but every rifle is different so loads with powder and bullets need to be worked up carefully and safely. This is a continuation of a series of articles here on this site highlighting the rifle, a Savage Model 12 Long Range Precision Rifle with the Leupold VX-3i 6.5-20 X 50mm. Both are a marriage made in heaven and work seamlessly together. See the image on the front page. In addition to this great marriage of rifle and scope we add Sierra 142 grain HPBT Match bullets lit by H4350 Powder seen in a recent article here.
Earlier articles used newer cases that were full length resized. Below I used cases that were twice used and neck sized. An advantage of using cartridge cases previously used in the same rifle is that they now fit the chamber perfectly and have a positive effect on group to a degree that is often noticeable. Since I am relatively new to the rifle some accuracy comes from the shooters comfort with the rifle, scope and loadings. That would be me! I reloaded the H4350 with slightly hotter loads for the Sierra 142 grain HPBT observing for signs of high pressure adding a tenth of a grain at a time at near max loads.
Weather sunny with 12 oclock 0 to 5 mph wind. Ideal!
Shooter – Ed Hale
Group 1 was a three shot group that I previously tested in an earlier article with the best being 0.235 inches. This group was 0.3 inches. No data measured.
Group 2 is a 5 shot group with a flyer using 40.5 grains powder. With the flyer it shot 0.7 inches. If take out the flyer it is 0.36 inches.
Range 23 fps
Population Standard Deviation, σ=7.9
This is a very tight spread.
Group 3 is a 5 shot group with 40.6 grains of H4350 measuring 0.34 inch spread.
Population Standard Deviation, σ=13.922643427166
Range is 37.
Best group with widest velocity range if the chronograph is correct. Best to repeat this test to be sure of the Range calculation.
Group 4 is a 5 shot group with 40.7 grains of H4350 measuring 0.69 inch spread and still no case or primer issues.
Population Standard Deviation, σ 7.5524830353997
Mean (Average): 2644.4
The Target tells some of the story.
Low Range and Std Dev σ is best.
I have added today 6/22/16 image
Tested H4350 at 41.1 grains Group 1 and G2 at 41.2 grains powder trying to achieve a speed of 2700 fps and I did.
UPDATE BELOW FOR 6/22/16
Group 1 on 6/22/16 41.1 grains was a cold barrel and the first shot pulled right 1/2 inch. the other 4 shots grouped less than 1/2 inch statisticical variation of range “R” in group 1 was 46 fps thus would exceed 3 sigma in standard deviations from the mean and will group poorly at long range.
2706,2693,2696,2659 One data point was not captured so i used the 4.
Population Standard Deviation, σ 17.69
Range R = 45
Mean (Average): 2688.5
Very poor long range reliability as the range and standard deviation conclude poor confidence.
Group 2 on 6/22/16 is 41.2 grains H4350 and measured 0.49 inches of 5 shots.
Chronograph of each shot 2687,2691,2708,2702,2687 in fps. Use an online Std Deviation calculator.
Population Standard Deviation, σ 8.5
Mean (Average): 2695
Range R=21 fps
This is excellent! Speed is there and the Standard Deviation is below 10 and with a range or spread of 21 fps the rifle should shoot very well at long distances with this load. A real winner and for all intent it is a 2700 fps load that can win at 600 yards in F class competition. I would like more speed but this will work.
Note there are barrel harmonic vibrations at play and each barrel is different. By testing in this way you are trying to shoot in the valley of the rifles harmonic vibrations. I did note that the barrel performed more consistent when it was warmed with a few shots first.
The quality and clarity of the Leupold VX-3i 6.5 -20 x50mm makes a huge difference for me the shooter. The image was so crisp that I could hold within 1/8th inch of crosshairs or less and is specifically designed for long range. At 100 yards I shot it at 14X. This scope has a side focus to reduce parallax. More on this scope soon!