Long range load development at 100 yards.
- Thread starter Erik Cortina
- Start date
Hello, all. This is my first post since recently joining the forum. Looks like a lot of great info here and many great folks, too.
I'm new to precision rifle and reloading. Stumbled across this thread and decided to give this method a try.
Savage 10 FCP-SR (new style) 20" barrel .308 Win.
175 TMK
H4895
Fireformed and necksized Federal brass
CCI Large Rifle Primers No. 200
edit: Wind near zero
Believe I have found my maximum charge and hoping to find a node nearby. Don't believe I can go any higher with powder charges.
Erik, I would be grateful if you would take the time to offer your opinion of the results below. Other opinions also welcome, of course.
Sorry for the cut and paste job on the 40.6 group. Was also doing a tall target test today and decided to also use it for load data. Lower right dot: shot at the wrong dot with one round. Drew the 'hole' in the proper location to the best of my ability. Dots are 1". Sorry, no chrono data - was too overcast today to even attempt, anyway.
I'm new to precision rifle and reloading. Stumbled across this thread and decided to give this method a try.
Savage 10 FCP-SR (new style) 20" barrel .308 Win.
175 TMK
H4895
Fireformed and necksized Federal brass
CCI Large Rifle Primers No. 200
edit: Wind near zero
Believe I have found my maximum charge and hoping to find a node nearby. Don't believe I can go any higher with powder charges.
Erik, I would be grateful if you would take the time to offer your opinion of the results below. Other opinions also welcome, of course.
Sorry for the cut and paste job on the 40.6 group. Was also doing a tall target test today and decided to also use it for load data. Lower right dot: shot at the wrong dot with one round. Drew the 'hole' in the proper location to the best of my ability. Dots are 1". Sorry, no chrono data - was too overcast today to even attempt, anyway.
Attachments
Hollywood said:
Thank you for taking the time to reply. Would you mind elaborating on the reasons why you chose that load? Not questioning your judgment, just trying to understand the thought process.
First let me start by saying I am no pro it took me a very long time to understand what the method was looking for. With that out of the way, if you take your group CENTERS and compare them for the minimum difference vertically among the different groups. You want the group center between 2-3 consecutive groups with the least vertical difference. That will give you a cushion on either side of the node once it is pinpointed further along the method. So if you throw a slightly different powder charge it won't have a large or any vertical poi shift. I chose the a load in between two consecuive that had almost identical group center locations. Hopefully that makes some sense to you.Broad Side said:
The chrony data is important so if there are two possible nodes to peruse you would go after the o e with the lowest SD.
Hollywood said:
Yes, thanks. Makes perfect sense to me.
Not far from my line of thinking. My best guess was that 41.0 - 41.8 were all pretty close with possibility of shooter making them look not as close. The two hot loads seemed a bit off and there's something about the groups that I don't like that makes me want to stay away from them. The light load seemed a little better. So, split the 41.0 - 41.8 and perhaps favor a bit to the lighter side. I tend to think just split it so, 41.4 or perhaps 41.3.
I hadn't considered the possibility of there being two nodes here. Don't know if my cheap chrono would show us if there are or not. All I can really tell you about muzzle velocity is that, as the powder charges went up, the groups kept rising to a point when it leveled out a lot. If memory serves, they started rising more again when charges went higher than in the above pic. Also started seeing pressure signs at that time.
Don't know if it matters but I should have mentioned that wind conditions were near zero.
Holding off on loading anything for now although it looks like Erik has been away from this thread for a while.
Anyone else want to take a crack at this?
Sheldon N said:Finished my seating depth test for my 280AI, going to go with 2.775 to ogive which is 10 thousandths off the lands.
VERY happy with how the rifle shoots the 180 hybrids. The first three groups are pretty much the three best groups I've ever shot.
Interesting - is 2.775 top right? To my eye the top left and middle look to be good choices as they are much closer aligned vertically where as the top right has a POI that is significantly lower than those two.
Great shooting. 2.775 looks good. Did you shoot any all the way to jam? That would help to see if 2.775 is in the middle or end of the node.Sheldon N said:Finished my seating depth test for my 280AI, going to go with 2.775 to ogive which is 10 thousandths off the lands.
VERY happy with how the rifle shoots the 180 hybrids. The first three groups are pretty much the three best groups I've ever shot.
Thanks guys.
Top left was used as a "fouler" target with four rounds loaded to 2.755 to ogive (30 thou off lands). I did that sort of as an afterthought rather than choosing to make it part of the test. Fired first round, reset my zero, then fired a group of three. I was surprised at how well it shot, it was actually the best group at 0.183".
The rest of the targets 1 through 5 started off at 5 thousandths off lands and worked up to 25 thousands off lands. I didn't shoot one touching lands. They were all shot in sequence, not round robin.
I look at target #3 as a two shot group. The "flyer" wasn't just a pulled shot, it was a "Bang! oh crap I didn't mean for the gun to go off" shot as I was settling into position. That's why I picked target #2 as the final seating depth since it had good groups on either side of it so it looked to be roughly in the middle of an acceptable node.
Do you guys use the POI method of selecting seating depth, same as you would for powder charges? I had thought I would look more at consistency of of group clustering rather than POI, since I can load seating depth repeatably to 0.001. I use the Redding competition die and measure every round with an ogive comparator tool.
As a side note, I'm not quite sure what happened with targets 4 and 5. It may have been me getting tired and losing concentration, the barrel getting hot, or simply not a good node. Probably all of the above. I would have expected target 5 to be better since it's only 5 thousands different than the first sighter/fouler target.
Top left was used as a "fouler" target with four rounds loaded to 2.755 to ogive (30 thou off lands). I did that sort of as an afterthought rather than choosing to make it part of the test. Fired first round, reset my zero, then fired a group of three. I was surprised at how well it shot, it was actually the best group at 0.183".
The rest of the targets 1 through 5 started off at 5 thousandths off lands and worked up to 25 thousands off lands. I didn't shoot one touching lands. They were all shot in sequence, not round robin.
I look at target #3 as a two shot group. The "flyer" wasn't just a pulled shot, it was a "Bang! oh crap I didn't mean for the gun to go off" shot as I was settling into position. That's why I picked target #2 as the final seating depth since it had good groups on either side of it so it looked to be roughly in the middle of an acceptable node.
Do you guys use the POI method of selecting seating depth, same as you would for powder charges? I had thought I would look more at consistency of of group clustering rather than POI, since I can load seating depth repeatably to 0.001. I use the Redding competition die and measure every round with an ogive comparator tool.
As a side note, I'm not quite sure what happened with targets 4 and 5. It may have been me getting tired and losing concentration, the barrel getting hot, or simply not a good node. Probably all of the above. I would have expected target 5 to be better since it's only 5 thousands different than the first sighter/fouler target.
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