Dr T
Member
While sitting in the departure section for Southwest at Houston Hobby today, my wife came up and tossed a magazine at me that she had found abandoned in a seat nearby. It was a copy of Guns&Ammo Precision Rifle Shooter 2019 Issue 2.
Now, I will be the first to admit that I am a bit of a snob when it comes to firearms literature (I generally just read Rifle and Handloader), but I was pleasantly surprised by this publication.
In particular, there is an article by Patrick Sweeney entitled "Inch by Inch" that publishes a summary of his findings for his study of the decrease in velocity for the 6.5 Creedmoor as its barrel is shortened from 24 inches to 7 inches. The velocities published are 10 shot averages for 6 different loads with bullet weights ranging from 125 gr to 147 gr. The data was collected with a LabRadar chronograph. While it does not have the 2nd order statistics (standard deviation and extreme spread), it is still one of the more complete studies of this topic I have seen in the popular literature and I commend the author on the discussion he provides.
Since I have only eyeballed the numbers so far (and have not done any number crunching of my own on his published averages), the spoiler is that it looks like about 20 to 30 fps per inch. I will feel better after I can run some regression lines on the data.
And, If it happens to be the magazine that was left behind by someone on THR, rest assured that it has fallen into good hands and I greatly appreciate it.
Now, I will be the first to admit that I am a bit of a snob when it comes to firearms literature (I generally just read Rifle and Handloader), but I was pleasantly surprised by this publication.
In particular, there is an article by Patrick Sweeney entitled "Inch by Inch" that publishes a summary of his findings for his study of the decrease in velocity for the 6.5 Creedmoor as its barrel is shortened from 24 inches to 7 inches. The velocities published are 10 shot averages for 6 different loads with bullet weights ranging from 125 gr to 147 gr. The data was collected with a LabRadar chronograph. While it does not have the 2nd order statistics (standard deviation and extreme spread), it is still one of the more complete studies of this topic I have seen in the popular literature and I commend the author on the discussion he provides.
Since I have only eyeballed the numbers so far (and have not done any number crunching of my own on his published averages), the spoiler is that it looks like about 20 to 30 fps per inch. I will feel better after I can run some regression lines on the data.
And, If it happens to be the magazine that was left behind by someone on THR, rest assured that it has fallen into good hands and I greatly appreciate it.
