So I shot my DTA SRS SAC 6.5 Creedmoor out to 1420 yards at a 12” wide chest-sized steel plate. I was shooting pointed 142gr SMK @2920fps.
Out of 40 shots total, without excluding “sighters” etc, I made hits on steel with 18 shots. This calculates out to be a 45% hit probability.
Now at first I was a little disappointed at myself. After all, there are so many posts on many forums, stating that you can easily make hits out pass a mile or whatever extreme distance with a 6.5 Creedmoor or whatever similar caliber easily because it doesn’t drop pass subsonic until you get to whatever extreme distance. There are also many posts that clearly state that if you shoot x amount of yards then this or that caliber is what is you want for whatever reason, some good advice but others not.
For example, with my shooting conditions and rifle, my bullet doesn’t go subsonic until about 1800 yds. So shouldn’t my 6.5 Creedmoor be at least an 1800 yds capable round if I “do my part”? What about all those guys shooting pass subsonic and getting “consistent hits no problem”?
First off, if I posted just the pic with only my hits and didn’t tell you about my misses that would look pretty great. Of course, no one does that.
Another factor to consider is that there are limited places where you can actually shoot that far safely and legally. I had to shoot from the top of a large hill to another, across a valley, up in the mountains, out in the desert, to get that far...of course in a secret location.
How about just having a range finder that can accurately range that far? A 20 yard ranging error (1.4%) at that distance would result in a 0.3mil difference in drop, or more than 15”, which is enough to completely miss the target. I used a Vectronix Terrapin on a tripod.
I was shooting in 3-5mph crosswinds or at least that is what my Kestrel told me. How about the different winds in the valley? Any wind swirling? Any winds during the bullet path at different distances not accounted for by my Kestrel at my shooting site?
Here’s the “big kicker”… With a 3mph wind that is a 0.7mil drift. With a 4mph wind that is a 0.9mil drift. With a 5mph that is a 1.1mil drift. So you would have to be able to estimate wind to within 1.5 mph and definitely less than 2mph, to be able to hit that 12” target "consistently" with this caliber.
I personally can’t estimate wind velocity to less than 2mph, so with my limitations, I only hit the target 45% of the time.
How about spin drift, variation in powder charge and velocity, velocity change with temperature, etc..etc.
Bryan Litz has a great book called “Accuracy and Precision for Long Range Shooting” that explains hit probabilities at different distances with different variables. This book put things such as how much of a difference another caliber will make for a shooter, depending on their ability, into perspective. I highly suggest reading this. Disclaimer that I don't get any benefit from him selling his books.
So at least for me, my 6.5 Creedmoor is not an 1800 yards nor 1420 yard “capable” round/rifle, as I don’t think such a low hit probability is acceptable depending on the situation and the ramifications of misses. There is much more than calculating when a caliber goes subsonic to determining it’s and your max efficiency range or the ideal caliber for shooting x distance.
I’m not trying to start an argument with anyone, as I’m sure that are many excellent shooters here, just food for thought. Thanks for reading.
Out of 40 shots total, without excluding “sighters” etc, I made hits on steel with 18 shots. This calculates out to be a 45% hit probability.
Now at first I was a little disappointed at myself. After all, there are so many posts on many forums, stating that you can easily make hits out pass a mile or whatever extreme distance with a 6.5 Creedmoor or whatever similar caliber easily because it doesn’t drop pass subsonic until you get to whatever extreme distance. There are also many posts that clearly state that if you shoot x amount of yards then this or that caliber is what is you want for whatever reason, some good advice but others not.
For example, with my shooting conditions and rifle, my bullet doesn’t go subsonic until about 1800 yds. So shouldn’t my 6.5 Creedmoor be at least an 1800 yds capable round if I “do my part”? What about all those guys shooting pass subsonic and getting “consistent hits no problem”?
First off, if I posted just the pic with only my hits and didn’t tell you about my misses that would look pretty great. Of course, no one does that.
Another factor to consider is that there are limited places where you can actually shoot that far safely and legally. I had to shoot from the top of a large hill to another, across a valley, up in the mountains, out in the desert, to get that far...of course in a secret location.
How about just having a range finder that can accurately range that far? A 20 yard ranging error (1.4%) at that distance would result in a 0.3mil difference in drop, or more than 15”, which is enough to completely miss the target. I used a Vectronix Terrapin on a tripod.
I was shooting in 3-5mph crosswinds or at least that is what my Kestrel told me. How about the different winds in the valley? Any wind swirling? Any winds during the bullet path at different distances not accounted for by my Kestrel at my shooting site?
Here’s the “big kicker”… With a 3mph wind that is a 0.7mil drift. With a 4mph wind that is a 0.9mil drift. With a 5mph that is a 1.1mil drift. So you would have to be able to estimate wind to within 1.5 mph and definitely less than 2mph, to be able to hit that 12” target "consistently" with this caliber.
I personally can’t estimate wind velocity to less than 2mph, so with my limitations, I only hit the target 45% of the time.
How about spin drift, variation in powder charge and velocity, velocity change with temperature, etc..etc.
Bryan Litz has a great book called “Accuracy and Precision for Long Range Shooting” that explains hit probabilities at different distances with different variables. This book put things such as how much of a difference another caliber will make for a shooter, depending on their ability, into perspective. I highly suggest reading this. Disclaimer that I don't get any benefit from him selling his books.
So at least for me, my 6.5 Creedmoor is not an 1800 yards nor 1420 yard “capable” round/rifle, as I don’t think such a low hit probability is acceptable depending on the situation and the ramifications of misses. There is much more than calculating when a caliber goes subsonic to determining it’s and your max efficiency range or the ideal caliber for shooting x distance.
I’m not trying to start an argument with anyone, as I’m sure that are many excellent shooters here, just food for thought. Thanks for reading.
