Zombie Steve
05-15-2014, 11:49
If you still think powder charge weight is the only variable in reloading, then this thread is for you. I think it will be helpful for new guys to reloading in illustrating a lot more variables in the process.
I recently rebarreled my hunting rifle to .338-06. I've gone through several rounds of load development to get to this point, and you guys know how to do a work up batch, so I'll skip ahead a little bit. I initially couldn't find bullets that I wanted, and am still forced to use powders that I have on hand. When I started load development, all I could find is 200 grain Hornady Interlocks and then 225 grain Interlocks. I now have some 200 grain Nosler Accubonds (what I wanted when I started out) and 225 grain Interbonds.
http://i183.photobucket.com/albums/x214/sbecht/33806bullets_zpsff7af6b8.jpg
Left to right - 200 grain Interlock, 200 grain Accubond, 225 grain Interlock, 225 grain Interbond.
Knowing this is a hunting load, I'm trying to find a balance of speed and accuracy. There are more accurate loads for all of these bullets, but not where I wanted them in terms of speed and vice versa. I found Varget worked best with the 200's and IMR 4350 worked best with the 225's. When the new bullets arrived, I went back out and tested again using the same brass and powder charge weights. The 225 Interbonds were plug and play. The same load I did for the Interlock worked very well. The 200 grain Accubonds... not so much.
Some interesting findings - The 225 grain bullets both shot about 2,600 fps. No way around it... IMR 4350 is temperature sensitive. At 45 degrees, they averaged 2,588 fps. At 65 degrees, they averaged 2,623fps. That's a big difference considering I'm usually hunting around 30 degrees. The group sizes were very good / 1 moa or better every time (different temps, different bullets).
With Varget, the speeds stayed the same on two occasions shooting the 200 grain Interlock bullets... both came in at 2,760 fps. Varget is as close as it gets to temp insensitivity. The interesting thing here is when I substituted 200 grain Accubonds, my speeds averaged 2,814 fps. Only the bullet was different. No pressure signs whatsoever, but the group more than doubled in size. I was getting a hair over 1moa with the 200 interlocks, and yesterdays groups... well... they are the two five shot groups at the bottom. The lower right group had just a touch of taper crimp to see if it made any difference. It did... it made it worse. I'd still hunt with it if I had to go tomorrow, but I can do better. Back to the drawing board with the Accubonds.
http://i183.photobucket.com/albums/x214/sbecht/33806target_zps2fb89935.jpg
Last variable - I took the 225 Interbond load and for giggles tried two other primers. These are the top three groups. Left to right, CCI large rifle, Remington 9-1/2 and Federal 210 Match. Yes, a really bad (but called) flyer in between the first and second diamond... that belonged to the Rem 9-1/2 batch.
With the different primers, velocities were all very close (less than 10 fps difference). Standard deviation was 19 for the CCI primers, 16 for the Remington and 6 for the Federal Match primer. For a 200 yard hunting rifle, it's academic, but if you're doing this for a target gun it becomes important at longer distances. Surprisingly, the CCI and Federal Match groups were the same size. Just under an inch at 100 yards. I think the potential for the match primers is better (three holes touching on the right, two touching a half inch away). I'll probably go that route. Side note - I did drink coffee before shooting yesterday morning. [Coffee]
So anyway, I'm still not totally done. I'd love to try H4350 as I think it's going to be a lot less sensitive to temperature swings than IMR 4350. I'm going to start fresh with Varget and the 200 grain Accubonds. I certainly like the idea of 2,800 fps with that bullet.
Again, I just wanted to illustrate for new guys how much can change from one bullet to the next, one primer to the next, et cetera. You might get away with switching components and you might not. The prudent thing to do if you're changing components is to back off and work back up. In these cases, I had already tested them and found out where max was. I felt certain a change of components where my previous accuracy loads were wasn't going to create an overpressure situation, and they didn't. If I was closer to max, I would have backed off and worked back up.
Thanks for reading. I hope you find this stuff as interesting as I do.
Now to find that damn bull elk during season...
I recently rebarreled my hunting rifle to .338-06. I've gone through several rounds of load development to get to this point, and you guys know how to do a work up batch, so I'll skip ahead a little bit. I initially couldn't find bullets that I wanted, and am still forced to use powders that I have on hand. When I started load development, all I could find is 200 grain Hornady Interlocks and then 225 grain Interlocks. I now have some 200 grain Nosler Accubonds (what I wanted when I started out) and 225 grain Interbonds.
http://i183.photobucket.com/albums/x214/sbecht/33806bullets_zpsff7af6b8.jpg
Left to right - 200 grain Interlock, 200 grain Accubond, 225 grain Interlock, 225 grain Interbond.
Knowing this is a hunting load, I'm trying to find a balance of speed and accuracy. There are more accurate loads for all of these bullets, but not where I wanted them in terms of speed and vice versa. I found Varget worked best with the 200's and IMR 4350 worked best with the 225's. When the new bullets arrived, I went back out and tested again using the same brass and powder charge weights. The 225 Interbonds were plug and play. The same load I did for the Interlock worked very well. The 200 grain Accubonds... not so much.
Some interesting findings - The 225 grain bullets both shot about 2,600 fps. No way around it... IMR 4350 is temperature sensitive. At 45 degrees, they averaged 2,588 fps. At 65 degrees, they averaged 2,623fps. That's a big difference considering I'm usually hunting around 30 degrees. The group sizes were very good / 1 moa or better every time (different temps, different bullets).
With Varget, the speeds stayed the same on two occasions shooting the 200 grain Interlock bullets... both came in at 2,760 fps. Varget is as close as it gets to temp insensitivity. The interesting thing here is when I substituted 200 grain Accubonds, my speeds averaged 2,814 fps. Only the bullet was different. No pressure signs whatsoever, but the group more than doubled in size. I was getting a hair over 1moa with the 200 interlocks, and yesterdays groups... well... they are the two five shot groups at the bottom. The lower right group had just a touch of taper crimp to see if it made any difference. It did... it made it worse. I'd still hunt with it if I had to go tomorrow, but I can do better. Back to the drawing board with the Accubonds.
http://i183.photobucket.com/albums/x214/sbecht/33806target_zps2fb89935.jpg
Last variable - I took the 225 Interbond load and for giggles tried two other primers. These are the top three groups. Left to right, CCI large rifle, Remington 9-1/2 and Federal 210 Match. Yes, a really bad (but called) flyer in between the first and second diamond... that belonged to the Rem 9-1/2 batch.
With the different primers, velocities were all very close (less than 10 fps difference). Standard deviation was 19 for the CCI primers, 16 for the Remington and 6 for the Federal Match primer. For a 200 yard hunting rifle, it's academic, but if you're doing this for a target gun it becomes important at longer distances. Surprisingly, the CCI and Federal Match groups were the same size. Just under an inch at 100 yards. I think the potential for the match primers is better (three holes touching on the right, two touching a half inch away). I'll probably go that route. Side note - I did drink coffee before shooting yesterday morning. [Coffee]
So anyway, I'm still not totally done. I'd love to try H4350 as I think it's going to be a lot less sensitive to temperature swings than IMR 4350. I'm going to start fresh with Varget and the 200 grain Accubonds. I certainly like the idea of 2,800 fps with that bullet.
Again, I just wanted to illustrate for new guys how much can change from one bullet to the next, one primer to the next, et cetera. You might get away with switching components and you might not. The prudent thing to do if you're changing components is to back off and work back up. In these cases, I had already tested them and found out where max was. I felt certain a change of components where my previous accuracy loads were wasn't going to create an overpressure situation, and they didn't. If I was closer to max, I would have backed off and worked back up.
Thanks for reading. I hope you find this stuff as interesting as I do.
Now to find that damn bull elk during season...