Long range load development at 100 yards.
- Thread starter Erik Cortina
- Start date
panzer075 said:
Not necessarily - if the lower node meets the requirement to stay above transonic at 1k and has accuracy, consistency etc then that's what I would look at....since you are having issues with ES at the higher node.
Erik states that seating depth nodes are .003" apart.
Probably the simplest way to decide what to do at this point is determine if the lowest node has the FPS to meet the 1k requirement. If so, run some load dev on that node and see if ES etc is better. If not you will possibly need to look at a component change such as the primer.
Anyways KISS it at the moment and check out your other node...one of the benefits of having two nodes
Well I am going to test the lower node...looks like 43.1-43.6 are all flat....so I am gonna try 43.4....
Now if that flops...has anyone found a primer change giving roughly the sane powder nodes...or do they usually change with a primer change? Wondering if the powder node is more about volume..???
Trying to see if I can save some components if possible...running low on bullets...
Now if that flops...has anyone found a primer change giving roughly the sane powder nodes...or do they usually change with a primer change? Wondering if the powder node is more about volume..???
Trying to see if I can save some components if possible...running low on bullets...
Erik Cortina
Team Lapua Brux Borden Captain
panzer075, do you take chrono readings when testing powder charge?
That is a very good point. I had under taken a sort of ladder test, to try and establish a maximum charge, so just reused those weights.6BRinNZ said:
I will load up 3 of the following and run them over a Magnetospeed:
- 43.0
- 43.2
- 43.4
- 43.6
- 43.8
- 44.0
It will be a while before I can get to a 100 yard day, but will post up then.
Thanks for your help,
Gareth
Erik Cortina
Team Lapua Brux Borden Captain
panzer075 said:
I believe that's the reason you are chasing your tail. Use the chrono during powder charge development but pay more attention to chrono numbers and where the ES is low and stable. Then move on to seating depth without chrono attached.
well looks like the issue was user error....somehow between the first seat test and the 2nd..i grabbed the wrong 8lb lot of varget and that's why I had issues..
went out this am with the right lot..and got very consistent results...as seating moved in towards the sweet spot ES went from 19-12-9-6-6 fps before going back up fairly gradually. so there is a great little window there for me at 44.2 g
Erik I have a new question...as the throat moves, do you seat the bullet out farther with it or is the seating depth preference of a barrel more of a constant of pressure and harmonics, that doesn't change much with erosion..? what are your thoughts?
went out this am with the right lot..and got very consistent results...as seating moved in towards the sweet spot ES went from 19-12-9-6-6 fps before going back up fairly gradually. so there is a great little window there for me at 44.2 g
Erik I have a new question...as the throat moves, do you seat the bullet out farther with it or is the seating depth preference of a barrel more of a constant of pressure and harmonics, that doesn't change much with erosion..? what are your thoughts?
Erik Cortina
Team Lapua Brux Borden Captain
panzer075 said:
You have to "chase" the lands as the throat erodes.
Here is my example of this process sucessfully working. Though I will admit, I did skip corners on the seating depth testing, only because I have had epxperience in using VLD's for a few calibers and have two seating depths that generally work well with them. I also dont have access to a reliable chronograph, so omitted that process as well. No point chasing your tail if you dont have an accurate chrony... I also have a large tuner on my rifle and that was set at 0 until all testing was finished.
So first off is testing powder charge. This case is the 284 shehane using a 180gr berger vld in a krieger 8.5 twist 5r barrel that I have been having trouble with for a while. Finally sorted my problem and had it rechambered ready to go.
I started with what I knew would be safe- 55.6gr powder- and since I knew a little about the VLD bullets and where they like seating wise, I chose a 10 thou jam. I went up in powder 0.2gr at a time as I knew I would see something fairly quickly. Sure enough 56 and 56.2 shot about the same POI. Excuse the damage to the paper, I stupidly had the target set up on a steel fence post.
Since 56 and 56.2gr were about the same POI, I really wanted to see 56.4gr shoot about the same as well- it would prove to me that I had a clear node that was large enough to have some room to move. Sure enough, another powder charge test and I was able to confirm it.
So 56.2 was going to be the middle charge to test. Quite possibly I could have gone higher but I was happy with the results so far.
So now was seating depth. Like I said, Ive used VLD's in a few different cals before and found them to work best at either 10 thou past touching, or around a 40 thou jump. In hindsight a better test would have been a 4, 7, 10, 13 and 15 thou jam or a 34, 37, 40, 43 and 46 thou jump. But I went straight to the depths I knew, plus 5 thou jam and 25 thou jump. Sometimes I have seen success with less of a jump and jam. In this again I was looking for similar POI's and the jumped loads showed more consistency in that for me. Take no notice of the powder charge written on the middle of the paper- Im definitely using 56.2gr.
Things were definitely looking good, and I was ready for the next stage of testing at our local range. We had a 300m f class shoot scheduled on electronic targets and it would be a great way to see how the tuner adjustments changed group size. Here are the photos.
Zero
Two
Four
Six
Eight- I did adjust my scope for this one (cant remember why)
After all this I turned the tuner back to 4 and left it there. The following weekend we had an 800m F class shoot planned and it would be good to see if the gun could hold its performance. We had a fairly switchy front fish tail wind which I knew wouldnt hold a very good waterline. It held about 1/4MOA at 300m when it was fairly light winds but would it at least be competitive?
As you can see it held about 3/4MOA which Im very happy with considering the conditions. My other 6.5mm barrel for this rifle holds fantastic waterline and I screwed it in to see what it did in the head wind conditions, and it shot the same scores, just not as good an X count as the 284 shehane that I was testing. I put that down to the BC advantage of the larger caliber. One of these shots out at 3 oclock is a sighter and all up it scored a 60.7X from 10 shots. Our scoring system is 6 points maximum per shot but would have been the equivalent of 100.7 for 10 shots in the USA.
I have decided that I will not be using any other method of load development in the future. This method clearly has the results to back it up. The only other thing I want to do is put the magnetospeed on it to see the velocity and ES. But in F class accuracy matters and I dont expect to be changing loads at all.
So first off is testing powder charge. This case is the 284 shehane using a 180gr berger vld in a krieger 8.5 twist 5r barrel that I have been having trouble with for a while. Finally sorted my problem and had it rechambered ready to go.
I started with what I knew would be safe- 55.6gr powder- and since I knew a little about the VLD bullets and where they like seating wise, I chose a 10 thou jam. I went up in powder 0.2gr at a time as I knew I would see something fairly quickly. Sure enough 56 and 56.2 shot about the same POI. Excuse the damage to the paper, I stupidly had the target set up on a steel fence post.
Since 56 and 56.2gr were about the same POI, I really wanted to see 56.4gr shoot about the same as well- it would prove to me that I had a clear node that was large enough to have some room to move. Sure enough, another powder charge test and I was able to confirm it.
So 56.2 was going to be the middle charge to test. Quite possibly I could have gone higher but I was happy with the results so far.
So now was seating depth. Like I said, Ive used VLD's in a few different cals before and found them to work best at either 10 thou past touching, or around a 40 thou jump. In hindsight a better test would have been a 4, 7, 10, 13 and 15 thou jam or a 34, 37, 40, 43 and 46 thou jump. But I went straight to the depths I knew, plus 5 thou jam and 25 thou jump. Sometimes I have seen success with less of a jump and jam. In this again I was looking for similar POI's and the jumped loads showed more consistency in that for me. Take no notice of the powder charge written on the middle of the paper- Im definitely using 56.2gr.
Things were definitely looking good, and I was ready for the next stage of testing at our local range. We had a 300m f class shoot scheduled on electronic targets and it would be a great way to see how the tuner adjustments changed group size. Here are the photos.
Zero
Two
Four
Six
Eight- I did adjust my scope for this one (cant remember why)
After all this I turned the tuner back to 4 and left it there. The following weekend we had an 800m F class shoot planned and it would be good to see if the gun could hold its performance. We had a fairly switchy front fish tail wind which I knew wouldnt hold a very good waterline. It held about 1/4MOA at 300m when it was fairly light winds but would it at least be competitive?
As you can see it held about 3/4MOA which Im very happy with considering the conditions. My other 6.5mm barrel for this rifle holds fantastic waterline and I screwed it in to see what it did in the head wind conditions, and it shot the same scores, just not as good an X count as the 284 shehane that I was testing. I put that down to the BC advantage of the larger caliber. One of these shots out at 3 oclock is a sighter and all up it scored a 60.7X from 10 shots. Our scoring system is 6 points maximum per shot but would have been the equivalent of 100.7 for 10 shots in the USA.
I have decided that I will not be using any other method of load development in the future. This method clearly has the results to back it up. The only other thing I want to do is put the magnetospeed on it to see the velocity and ES. But in F class accuracy matters and I dont expect to be changing loads at all.
Erik Cortina
Team Lapua Brux Borden Captain
BY1983, clearly your gun is shooting well. Now on to tackling the wind, and I don't have a short cut for that! 
Thanks Erik
Yes very happy with it for now. I have been thinking that I would get another 6.5mm barrel for soon, now Im just not sure. This 7mm can do everything it can and more. The only cost is very miniscule amount of recoil. Im shooting the shehane free recoil anyway and it doesnt bother me one bit. Since we do so much short range shooting here as well, I may just adopt a 6mm and 7mm approach for my f class shooting and slowly do away with the 6.5mm
I must admit I was skeptical of this method at one stage. 100yds/meters is a long way from 1000yds or 900m. But it all seems to be working very well. Congratulations on this thread and I hope people can see the benefits of it.
Yes very happy with it for now. I have been thinking that I would get another 6.5mm barrel for soon, now Im just not sure. This 7mm can do everything it can and more. The only cost is very miniscule amount of recoil. Im shooting the shehane free recoil anyway and it doesnt bother me one bit. Since we do so much short range shooting here as well, I may just adopt a 6mm and 7mm approach for my f class shooting and slowly do away with the 6.5mm
I must admit I was skeptical of this method at one stage. 100yds/meters is a long way from 1000yds or 900m. But it all seems to be working very well. Congratulations on this thread and I hope people can see the benefits of it.
dragman
Site $$ Sponsor
Ok, at what point after the development has been done at 100 yards and the groups, nods, and ES are all where we want them do we call it finished? Do you check it out long and if so what do you need to see to be satisfied with the load development being "done" just wondering
[br]BY1983 said:
Looks like it is shooting well. I disagree with one point. In Long Range F-Class, accuracy and low ES matters. One without the other is relatively useless.
Steve- not disagreeing with you there- of course I plan to test it for ES. But at the end of the day if Im capable of hitting that kind of score in a vertical condition Im not going to argue with what the target is saying. If my ES is around 15-20 I will take it and not change a thing- bar maybe trying a charge 0.2 and 0.4gr higher to just see where the top end of my node is.
Dragman- thats why I have finished my testing at longer ranges. Not everyone is lucky enough to have them- but electronic targets are a very handy tool to use for load development. Once I was happy with it holding 1/4MOA vertical at 300m I shot a string at longer range. 800m I think is pretty close to 900 yds. With our range its quite rare to get a full horizontal group as its surrounded by pine trees. Any prevailing condition tends to get channeled down range and turns into a vertical condition. You can even see at 300m I had two vertical points of impact- purely due to that vertical. I wouldnt say testing is over, but I dont plan on changing loads until I get access to a friends magnetospeed and possibly see that the ES isnt quite right. Until that happens if I can prove the load can shoot 60's with a decent X count at 900m or 1000yds and also at 300m again, Im happy to compete with this rifle.
Dragman- thats why I have finished my testing at longer ranges. Not everyone is lucky enough to have them- but electronic targets are a very handy tool to use for load development. Once I was happy with it holding 1/4MOA vertical at 300m I shot a string at longer range. 800m I think is pretty close to 900 yds. With our range its quite rare to get a full horizontal group as its surrounded by pine trees. Any prevailing condition tends to get channeled down range and turns into a vertical condition. You can even see at 300m I had two vertical points of impact- purely due to that vertical. I wouldnt say testing is over, but I dont plan on changing loads until I get access to a friends magnetospeed and possibly see that the ES isnt quite right. Until that happens if I can prove the load can shoot 60's with a decent X count at 900m or 1000yds and also at 300m again, Im happy to compete with this rifle.
Let's say you have two identified nodes. The lower node has a ES of 5 but the higher node has an ES of 20 but shoots tighter groups with less vertical at midrange. vCould a tuner be used to tighten the lower node with the lower ES for long range shooting? This was after the 100 yard test and seating depth test were done?
Erik Cortina
Team Lapua Brux Borden Captain
jsthntn247 said:
Seating depth and tuner will take care of you.
Hi Erik,
I went ahead and adjusted seating depth with the powder load that you recomended.
The following are the MV (FPS) for each seating depth adjustment:
-0.010 = 2882, 2878, 2882.
-0.013 = 2898, 2893, 2878.
-0.016 = 2895, 2869, 2879.
-0.019 = 2870, 2875, 2865.
-0.022 = 2890, 2856, 2847.
-0.025 = 2867, 2880, 2867.
-0.028 = 2858, 2843, 2868.
-0.031 = Error, 2866, 2867.
-0.034 = 2847, 2848, 2879.
-0.037 = 2853, 2848, 2846.
-0.040 = 2875, 2854, 2861.
Please let me know what you think.
Thanks
I went ahead and adjusted seating depth with the powder load that you recomended.
The following are the MV (FPS) for each seating depth adjustment:
-0.010 = 2882, 2878, 2882.
-0.013 = 2898, 2893, 2878.
-0.016 = 2895, 2869, 2879.
-0.019 = 2870, 2875, 2865.
-0.022 = 2890, 2856, 2847.
-0.025 = 2867, 2880, 2867.
-0.028 = 2858, 2843, 2868.
-0.031 = Error, 2866, 2867.
-0.034 = 2847, 2848, 2879.
-0.037 = 2853, 2848, 2846.
-0.040 = 2875, 2854, 2861.
Please let me know what you think.
Thanks
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