A few weeks ago I worked up a load for my Obermeyer 5R barreled Weatherby .260.
I ended up with R&P brass, R&P primers, 42 grains of H4350 and 140 Amax bullets seated at 2.825. This load shoots really tight and chronographed at 2745 average at the time, velocity deviation was within 12 fps.
Due to recent events, jackasses have been panick buying just about everything gun related, including H4350. Since i couldn't find any, i picked up 8 lbs of the closest thing i could find, which was AA4350.
I loaded 5 rounds with 41.6 grains, [email protected], 5@42, [email protected], all seated to 2.825 like my H4350 load and went to the range. Here were the results.
41.6 AA4350 = 2700 fps ave
41.8 AA4350 = 2500-2525
42.0 AA4350 = 2500-2525
42.2 AA4350 = 2500-2530
Pressure signs were fairly normal, looked just like the primers on my H4350 loads. They shot to the same zero/poi as my H4350 load. Accuracy was good for all loads, about .5-.7 moa, with most of the group error being horizontal due to a 10 wind.
So I was thinking this AA4350 stuff must really be slow compared to H4350, so i broke out some of the H4350 loads from a few weeks before and was surprised when they also chronographed @ 2500 fps.
The chronograph is an RCBS. The plastic one that all fits into a bullet shaped housing and feels like it was made in china for about 50 cents.
It was weird that the 41.6 grain load showed 2700 fps, which is about what I expected from that load, but the hotter loads were significantly slower. All the loads powder charges were hand weighed individually.
Could my scale be screwed up, or the chronograph? It was 30 degrees this morning and 60 3 weeks ago when i came up with the h4350 load. 200+ fps difference over a 30 degee temp change seems to defy physics.
I ended up with R&P brass, R&P primers, 42 grains of H4350 and 140 Amax bullets seated at 2.825. This load shoots really tight and chronographed at 2745 average at the time, velocity deviation was within 12 fps.
Due to recent events, jackasses have been panick buying just about everything gun related, including H4350. Since i couldn't find any, i picked up 8 lbs of the closest thing i could find, which was AA4350.
I loaded 5 rounds with 41.6 grains, [email protected], 5@42, [email protected], all seated to 2.825 like my H4350 load and went to the range. Here were the results.
41.6 AA4350 = 2700 fps ave
41.8 AA4350 = 2500-2525
42.0 AA4350 = 2500-2525
42.2 AA4350 = 2500-2530
Pressure signs were fairly normal, looked just like the primers on my H4350 loads. They shot to the same zero/poi as my H4350 load. Accuracy was good for all loads, about .5-.7 moa, with most of the group error being horizontal due to a 10 wind.
So I was thinking this AA4350 stuff must really be slow compared to H4350, so i broke out some of the H4350 loads from a few weeks before and was surprised when they also chronographed @ 2500 fps.
The chronograph is an RCBS. The plastic one that all fits into a bullet shaped housing and feels like it was made in china for about 50 cents.
It was weird that the 41.6 grain load showed 2700 fps, which is about what I expected from that load, but the hotter loads were significantly slower. All the loads powder charges were hand weighed individually.
Could my scale be screwed up, or the chronograph? It was 30 degrees this morning and 60 3 weeks ago when i came up with the h4350 load. 200+ fps difference over a 30 degee temp change seems to defy physics.
