Ok guys-I made it out to the range today before leaving for WY-you knew I had to, right? [emoji38]
I am observing a speed plateau with this bullet, this powder loading, in my gun.
So, within the parameters already shared, I ran a chrono test earlier today; 3 rounds each using AA4350 and the 145 gr Speer BTSP:
53.4 gr: 2,687 2,693 2,690
Avg= 2,690 Std Dev= 2.45
53.7 gr: 2,649 2,681 2,710
Avg= 2,680 Std Dev= 24.91
Its a small sample size, but FWIW, the stats support the idea of a velocity plateau. The hotter charge averaged lower speed and has more spread.
I checked the chrono with my older lower performance load-3 shots before the aforementioned test-and it checked out ok.
I am left with this:
1. A velocity limit has been reached
2. My scale is messed up? (not exactly supported by the consistent performance of the 53.4 gr load)
3. Bad powder
4. I may had some chrono problems and copper fouling issues when 2,805 fps was measured a few weeks back at the 53.4 gr charge
I've run out of time for tweaking this anymore before hitting the plains. I will use 53.4 gr and adjust my holdovers accordingly. I have target data at 100, 200 yards that is rock solid with 53.4 gr. I am dissapointed I am not getting the speed I want, but can take solace in the high accuracy of the load.
Certainly keep the thread going if there's interest.
This isn't the end of the story - something to mess with when I get back. Now, off to finish packing! [emoji6]
Regards,
Sent from my SAMSUNG-SGH-I337Z using Tapatalk
I am observing a speed plateau with this bullet, this powder loading, in my gun.
So, within the parameters already shared, I ran a chrono test earlier today; 3 rounds each using AA4350 and the 145 gr Speer BTSP:
53.4 gr: 2,687 2,693 2,690
Avg= 2,690 Std Dev= 2.45
53.7 gr: 2,649 2,681 2,710
Avg= 2,680 Std Dev= 24.91
Its a small sample size, but FWIW, the stats support the idea of a velocity plateau. The hotter charge averaged lower speed and has more spread.
I checked the chrono with my older lower performance load-3 shots before the aforementioned test-and it checked out ok.
I am left with this:
1. A velocity limit has been reached
2. My scale is messed up? (not exactly supported by the consistent performance of the 53.4 gr load)
3. Bad powder
4. I may had some chrono problems and copper fouling issues when 2,805 fps was measured a few weeks back at the 53.4 gr charge
I've run out of time for tweaking this anymore before hitting the plains. I will use 53.4 gr and adjust my holdovers accordingly. I have target data at 100, 200 yards that is rock solid with 53.4 gr. I am dissapointed I am not getting the speed I want, but can take solace in the high accuracy of the load.
Certainly keep the thread going if there's interest.
This isn't the end of the story - something to mess with when I get back. Now, off to finish packing! [emoji6]
Regards,
Sent from my SAMSUNG-SGH-I337Z using Tapatalk