wsmallwood
Member
I've read Bob Collins' Eley By the Numbers several times. I would probably read it again but don't know where to find it though I'm sure it's posted somewhere.
But that leads me to my quest for various opinions. How much does velocity affect ammo accuracy assuming we're talking about match level ammo? If we make the assumption that posted velocities are correct, does it matter that much? If I recall Bob's article correctly he essentially said you need faster ammo in colder conditions. I think that's probably right because biathlon ammo is sometimes as high as 1099 fps. But I also remember somewhat the discussion of density altitude and the fact hat hotter humid air is thinner than colder less humid air. As I recall, reading the article gave me the impression of a "U" shaped curve in terms of velocity. Higher velocity was needed at low temps to allow it push through the dense air, but also needed at high temps to allow stability. Mid velocity somewhere in the middle.
I don't know if that interpretation is right or not because it would seem, on the surface, that if higher speed ammo works better in cold temperature, then slower speed would work better in higher temperature.
Eley is the only company I know of that posts the velocity and how accurate those velocities are I have no idea. But it seems to run no lower than 1030 and not much higher than 1080 until you get into the biathlon stuff. So, the first question is, does that 50 fps really make a difference at all in the typical temperature range of RFBR? The second is what is the optimum velocity range for what we generally shoot if it does make a difference. Personally I shoot most targets from about 70 degrees to about 90 degress F. The majority of those are in the high 80's and usually very humid. A posted 1056 fps has been my best ammo several times.
I recently tested 12 lots of Eley. The temperature during testing ran from around 50-52 degrees F and the wind was certainly noticed. The best three lots that I tested were all posted at 1052 fps. Although two stood out, all three held true to what I consider the most important part of the Eley lot analyzer. Two are completely gone now. One was one of the best in terms of group size from the analyzer. For my rifle I would not have bought it but I think the group size from the analyzer sold it. The other that sold out was not the best in terms of group size on the analyzer but according to the analyzer did have one great attribute. I think it sold because it was tested. The one I chose was very similar to the one just mentioned with a little better grouping according to the analyzer. It was really a hard choice for me but I ultimately chose the one that shot the slightly smaller groups for me in the exact same conditions.
I think to some extent we all second guess ammo choices. That's one reason I rarely buy a case of anything. But the one I chose is still sitting there with many boxes available. Kinda makes me worry, but not much. It seemed to be consistent in the hurricane we shot in Saturday even though I shot very low scores.
What I really wonder is if ammo that is at the two extremes in velocity will shoot in changing weather conditions. I've had very good 1081 fps ammo that only shot when it was hot, when I was being told it was too fast for hot weather. I've had 1035 fps that shot very well in the cold and was great on a cool night but also shot very well in the heat and humidity.
So does velocity really matter within the range we shoot given the ammo we shoot? Will ammo that tests very good remain true to that test when the temperature rises 40 degrees? I know it's all opinion, but all opinions are welcome.
But that leads me to my quest for various opinions. How much does velocity affect ammo accuracy assuming we're talking about match level ammo? If we make the assumption that posted velocities are correct, does it matter that much? If I recall Bob's article correctly he essentially said you need faster ammo in colder conditions. I think that's probably right because biathlon ammo is sometimes as high as 1099 fps. But I also remember somewhat the discussion of density altitude and the fact hat hotter humid air is thinner than colder less humid air. As I recall, reading the article gave me the impression of a "U" shaped curve in terms of velocity. Higher velocity was needed at low temps to allow it push through the dense air, but also needed at high temps to allow stability. Mid velocity somewhere in the middle.
I don't know if that interpretation is right or not because it would seem, on the surface, that if higher speed ammo works better in cold temperature, then slower speed would work better in higher temperature.
Eley is the only company I know of that posts the velocity and how accurate those velocities are I have no idea. But it seems to run no lower than 1030 and not much higher than 1080 until you get into the biathlon stuff. So, the first question is, does that 50 fps really make a difference at all in the typical temperature range of RFBR? The second is what is the optimum velocity range for what we generally shoot if it does make a difference. Personally I shoot most targets from about 70 degrees to about 90 degress F. The majority of those are in the high 80's and usually very humid. A posted 1056 fps has been my best ammo several times.
I recently tested 12 lots of Eley. The temperature during testing ran from around 50-52 degrees F and the wind was certainly noticed. The best three lots that I tested were all posted at 1052 fps. Although two stood out, all three held true to what I consider the most important part of the Eley lot analyzer. Two are completely gone now. One was one of the best in terms of group size from the analyzer. For my rifle I would not have bought it but I think the group size from the analyzer sold it. The other that sold out was not the best in terms of group size on the analyzer but according to the analyzer did have one great attribute. I think it sold because it was tested. The one I chose was very similar to the one just mentioned with a little better grouping according to the analyzer. It was really a hard choice for me but I ultimately chose the one that shot the slightly smaller groups for me in the exact same conditions.
I think to some extent we all second guess ammo choices. That's one reason I rarely buy a case of anything. But the one I chose is still sitting there with many boxes available. Kinda makes me worry, but not much. It seemed to be consistent in the hurricane we shot in Saturday even though I shot very low scores.
What I really wonder is if ammo that is at the two extremes in velocity will shoot in changing weather conditions. I've had very good 1081 fps ammo that only shot when it was hot, when I was being told it was too fast for hot weather. I've had 1035 fps that shot very well in the cold and was great on a cool night but also shot very well in the heat and humidity.
So does velocity really matter within the range we shoot given the ammo we shoot? Will ammo that tests very good remain true to that test when the temperature rises 40 degrees? I know it's all opinion, but all opinions are welcome.