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Hi guys, the last two weeks I have been doing some experimental work with the Lyman 266469 using H4895. I was quite pleased with the results, but crossed a threshold for the worse around 100-150 fps lower than where I wanted to be! For the moment the H4895 seems to have maxed out at 26-27 grains! I took the M96 out to the range on Saturday. I began using Varget where I left off with H4895. The conditions where 56F misty and very calm, wind 2-4 mph. So pretty good shooting conditions. The shoot were all taken from 100 yards. Using the 266469 Lyman 140 grain projectile (coming out of the mould at 143 grains) GC with Hornady copper checks, lubed in the groves using Caranuba red. I conducted testing on 12 loads, using ten shot except for the last load (I will get to that). I shot 5 rounds, and then gave the barrel 5 minutes to cool to ambient temperature before shooting the second set of 5 rounds for the 10 shot group. The results are as follows: Group 1 26.5gns 4 3/4" (8 shots) 1825FPS Disappointing though it was pointed out to me that varget does not burn too well at lower pressures! This inconsistent burn was further demonstrated by two flyers. The brass didn't offer any of the tell tale neck splitting that usually accompanies flyers. I can not measure pressure but Quick-load indicates 1800PSI. Group 2 27gns 4 3/8" (9 shots) 1880FPS Ditto to above, 1 flyer. Group 3 27.5gns 3 9/16" 1990fps Ditto Group 4 28 gns 4 1/4" 1980fps Ditto Group 5 28.5gns 3 3/8" 2040fps Ditto Group 6 29 gns 2 7/8" 2070fps First sub 3 MOA, perhaps the Varget has got burning a bit better (estimated PSI 22000) Group 7 29.5gns 2 1/2" 2100fps The best group, it seems to be the sweet spot for Varget. Group 8 30 gns 2 11/16" 2135fps It seemed that pressure, RPM, velocity etc had begun to exceed a threshold! Group 9 30.5gns 3 3/4" 2170fps The threshold seems to now have been exceeded. Group 10 31 gns 5 1/4" (8 shots 2 flyers) 2210fps If there was any question this projectile is now getting pushed too hard. Group 11 31.5 gns 6 11/16" (7 shots 3 flyers) 2260fps All gone to pot! Group 12 32 gns I only shot three, the first two 10" apart and the third off target! Just too much for the combination, surprising though no sign of leading! Quickkload estimate the pressure to be up around 29000PSI. With the exception of around the 29-30 grains load range Varget proved largely unsuccessful as an accurate HV powder. Indeed at a little less velocity 1970fps, H4895 proved to be a more accurate option. I will repeat 29-30 grains at 200 yards to see what I get, as well as some of my H4895 loads. The next slowest powder is H4350 loading of that would need to begin at 33 grains! As some of you may have read from another post I discussed reduced loads of H4350 would a reduction of 10% be too much? | ||
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