6.5 Swede 10 Round Load Development

[NCIowan]

Need some help. I am a newbie at using this ladder test and would appreciate any suggestions on where to go from here. I ran three ladders, one ladder each for Reloader 19, Reloader 22, and Viht N560. The rifle is a Barrett 6.5x55 Swede, 24" barrel. Bullet is a 135 gr. BIB. Primer is a CCi200. I didn't experience any pressure signs such as stiff bolt etc. Do you think I should extend any of these ladders to a larger powder charge? Which flat spots would you pick to develop a load at? Thanks in advance for your help.
Reloader 19-------------------Reloader 22--------------------N560
49.4-----2,898...................48.0----2,869...................48.2----2,765
49.6-----2,911...................48.2----2,871...................48.4----2,847
49.8-----2,950...................48.4----2,920...................48.6----2,885
50.0-----2,944...................48.6----2,942...................48.8----2,878
50.2-----2,974...................48.8----2,943...................49.0----2,877
50.4-----2,992...................49.0----2,944...................49.2----2,901
50.6-----3,013...................49.2----2,951...................49.4----2,914
50.8-----3,026...................49.4----2,998...................49.6----2,942
51.0-----3,046...................49.6----2,989...................49.8----2,945
51.2-----3,056...................49.8----2,993...................50.0----2,966
It appears all three flattened out in the 2,950 fps area...
Thanks, Duane

 

[Sheldon N]

Agree that the 2945fps node is pretty clearly pronounced. It shows up best in Reloader 22, that's a huge window almost 0.8 grains wide with no velocity change.

I'd load 5 each at 49.9 of RL 19, 48.8 of RL22, and 49.7 of N560 and see what groups the best and gives the best SD/ES. My guess is RL22 is the best.

 

[NCIowan]

Agree that the 2945fps node is pretty clearly pronounced. It shows up best in Reloader 22, that's a huge window almost 0.8 grains wide with no velocity change.

I'd load 5 each at 49.9 of RL 19, 48.8 of RL22, and 49.7 of N560 and see what groups the best and gives the best SD/ES. My guess is RL22 is the best.

Excellent. I'll do that and post the results. Thanks

 

[mongo chicago]

Actually, I believe that the ladder test was developed for accuracy and not velocity. You you would load in half grain increments (or full if that floats your boat). You would then fire your 10 rounds or how many you had to try, from the lightest to the heaviest. At some point, you would get several rounds grouping closer together than the others. That would be where you would start tweaking your loads at. What good is doing it for a velocity check if accuracy suffers?
But I could be wrong.

 

[NCIowan]

Actually, I believe that the ladder test was developed for accuracy and not velocity. You you would load in half grain increments (or full if that floats your boat). You would then fire your 10 rounds or how many you had to try, from the lightest to the heaviest. At some point, you would get several rounds grouping closer together than the others. That would be where you would start tweaking your loads at. What good is doing it for a velocity check if accuracy suffers?
But I could be wrong.

You are right Mongo. That is the way I have developed loads in the past. What I am trying now is something I read about in 6.5 guys. Some call it Satterly's 10 Round Load development. It is a different approach to finding "the" load by finding the velocity flat spot and then testing to see how the performance of the groups are in that area. The interesting thing is how the velocity leveled off in the neighborhood of 2,950 fps with all three powders. This velocity may be my rifle's "sweet" spot with more than just these three powders, for this particular bullet. The idea is to find or get in the "neighborhood" of the load that my rifle likes with less rounds. I hope I have as much success with this as has been reported. Will be easier on the pocket and barrel. I am going to load up the three loads Sheldon N suggested and see where the ES, SD is and how they group. Will post the results here.

 

[brantfredrickson]

Gun nut, that is some interesting data showing that one powder has a wider node than others. I too have watched all three of the 6.5 guys videos on load development and found it applicable to my efforts. As a recreational shooter I shoot 50 rounds at 100 yards when I go to the range. At 100 yards using the targets as data it sometimes is like reading tea leaves, but the velocity from the magnetospeed makes it easier to spot nodes and their width. Today I'm going to look for a lower wide node that will cover a 22 deg F increase in action temperature that occurs for me when I shoot 50 rounds. It never occurred to me that I might have to change powders. Thanks for your post!

 

[NCIowan]

Gun nut, that is some interesting data showing that one powder has a wider node than others. I too have watched all three of the 6.5 guys videos on load development and found it applicable to my efforts. As a recreational shooter I shoot 50 rounds at 100 yards when I go to the range. At 100 yards using the targets as data it sometimes is like reading tea leaves, but the velocity from the magnetospeed makes it easier to spot nodes and their width. Today I'm going to look for a lower wide node that will cover a 22 deg F increase in action temperature that occurs for me when I shoot 50 rounds. It never occurred to me that I might have to change powders. Thanks for your post!

Neat idea. Will be interesting to see the results from increased action temperature on temperature sensitive powders. The day I fired the ladders the temperature was 80F with a 18mph wind coming from the 2:00 position. I spaced each shot 4 minutes apart...in an attempt to keep the action/barrel temperature "somewhat" constant and luke-warm to touch.

 

[watercam]

FWIW while I realize that you are shooting a 135 gr. bullet, you are somewhat above maximum for the 6.5x55. Check your primer shoulders on anything above 47.5 gr.. If the corners are flowing outward towards the side of the primer hole and there is little to no gap, you are probably over pressure. Bolt lift need not be stiff to be over the safe limit.

 

[NCIowan]

FWIW while I realize that you are shooting a 135 gr. bullet, you are somewhat above maximum for the 6.5x55. Check your primer shoulders on anything above 47.5 gr.. If the corners are flowing outward towards the side of the primer hole and there is little to no gap, you are probably over pressure. Bolt lift need not be stiff to be over the safe limit.

Thanks Waterman. You addressed one of the concerns I have. One of the toughest decisions I had on this ladder test was the powder charge starting point. I have resized and deprimed the cases already. So I will need to check the primer condition the next time I am at the range. Good stuff Waterman. Thanks for sharing.

 

[NCIowan]

FWIW while I realize that you are shooting a 135 gr. bullet, you are somewhat above maximum for the 6.5x55. Check your primer shoulders on anything above 47.5 gr.. If the corners are flowing outward towards the side of the primer hole and there is little to no gap, you are probably over pressure. Bolt lift need not be stiff to be over the safe limit.

Thanks Watercam. Went to the range this morning with the intention to shoot a five shot group for each powder's flat spot. You were "spot on". Each powder loading exhibited excessive pressure. A very stiff bolt and a flattening of the primers. I didn't attempt to shoot the five-shot groups. Not certain why the pressure was so evident today. Temperature was 20 degrees lower today compared to the day I shot the ladders. The only difference I am aware of is the ladders were shot with new Lapua brass and this morning I used the same brass but it was fired once and full length resized.

It looks like I will have to start over and re-shoot the ladders starting at lower powder charge levels. Will keep you posted.

 

[CharlieNC]

Not any confidence in this technique at all and the reasons are nearly too many to list. I am however interested to see if anyone can provide definitive evidence vs anecdotal "worked for me".

 

[ImBIllT]

As far as pressure, you need to know what kinda of data you have. Some is loaded down for use in military actions and some is not. Of course, if you're getting pressure signs, then you're there.

 

[Homerange]

Thanks Watercam. Went to the range this morning with the intention to shoot a five shot group for each powder's flat spot. You were "spot on". Each powder loading exhibited excessive pressure. A very stiff bolt and a flattening of the primers. I didn't attempt to shoot the five-shot groups. Not certain why the pressure was so evident today. Temperature was 20 degrees lower today compared to the day I shot the ladders. The only difference I am aware of is the ladders were shot with new Lapua brass and this morning I used the same brass but it was fired once and full length resized.

It looks like I will have to start over and re-shoot the ladders starting at lower powder charge levels. Will keep you posted.

There's your problem ^, you've changed the case volume and that will have a massive effect on pressures if you are anywhere near max already.
There's every chance you can get back to the velocities you had without high pressures but you'll have to work up to it again using the same case prep that results in less capacity than with new cases.

 

[Clucknmoan]

Not any confidence in this technique at all and the reasons are nearly too many to list. I am however interested to see if anyone can provide definitive evidence vs anecdotal "worked for me".

I guess I will hang my as a over the fence for a flaming! I have used this method to work the last few loads and it has seemed to work out well for me. I am curious to know if everyone thinks it's luck or if there is something to it. I'm not loading for a bench rest though, a combo of hunting, LR Steel and some PRS. One was a 6.5x284 and the other was my .223, both savages.

Started by loading 3 shells a piece with moderate powder charges at 3 different seating depths, .005, .035, .065 off. Would have loaded another at .095 off but both rifles had short throats. Shot these at 100 to get a ballpark of what kind of jump would shoot. For each rifle, there was a pretty clear winner.

Took that depth and loaded 10 shells in .02 grain increments, making sure the last couple were above book max. Shot these at 100 as well over a chrony, documented velocity and looked for pressure as the charge increases. The velocity will increase rapidly for .6 of a grain or so, then flatten out for .4 or so it seems. At the same time I shoot these 10 rounds in a half assed OCW, it's only 1 round per charge and not very scientific but it does seem to work it's way from one POI to the other as you would expect in an OCW. The OCW and velocity results seem to match.

I then load 5 in the center of that flat spot and see how they shoot. If they shoot, I load 10 more. So far they have shot well and have decent ES. I then jump straight to shooting steel at 400, then at 800 to verify results.

Again, this isn't for benchrest. Both these rifles shoot consistent in the .3's. I might be able to get them better but I hate to waste barrel life when. It will definately do what I need.

So is thus luck or is there something to it?

 

[Sheldon N]

Thanks for sharing Cluck. I'm also slowly feeling out how to incorporate this type of data into a workable singe test that gives me solid data I can rely on for load development. What I've settled on is that I want the velocity data, but I also want POI data (like an OCW) and I want to see how the loads group. I've done the velocity ladder alone and found that while it got me in the ballpark I always was looking for more info.

I did a test this afternoon for a new barrel on my PRS rifle in 6 Dasher with the 105 Hybrid. Loaded 3 shots each at 32.0, 32.2, 32.4, 32.6, and 32.8gr of Varget, 20 thou jump. Shot over a chrono and got velocity data for all rounds, could view 3 shot groups on target, and could look at velocity spread (SD/ES) at each charge weight.

What the test showed is that velocity flattened between 32.4 and 32.6gr, the POI on target was consistent between 32.2 and 32.6 and the best groups were at 32.4 and 32.6. 32.6 also had the lowest SD overall.

I'll probably run at the upper end of the node given that it's still warm now but we're going into the colder months ahead. Cooler temps and barrel slowing down over time will pull me toward the lower end of the node, but I should have a good amount of time before I need to do any tuning.

All in all a lot of good info out of 15 rounds.

 

[CharlieNC]

Sorry, no intent to flame you Chuck. This approach is very interesting and i would like to see it work as it is straightforward. During load development I have never observed a velocity node, but do see on the target. I'm no ballistician but cannot think of why this would occur, esp for seating depth. Thats why I would be interested to see the a correlation of nodes by velocity vs poi across the charge wt range.

 

[brantfredrickson]

I have sort of modified the 10 round test. lets say I have five charge weights I want to study, 39.6, 39.8, 40.0, 40.2, and 40.4. I shoot five shots at each charge weight, then four shots at each charge weight, and finally five shots at each charge weight. I take velocities on all charge weights, but I group the four and five shot groups and pull average, high, low, SD, and ES on the four and five groups. In addition I measure the temperature of the action barrel joint to see have much it rises during the test. It will rise about 15 degrees, If someone calls a cease fire, and 22 degrees if no cease fire is called. This way I can see what happens to the node over fifty shots, And it moves a little bit. Today I will do the same thing with five seating depths. I will study .075, .060, .045, .030, and .015.

 

[mikecr]

You've already exceeded 10 rounds in your '10 round load development system'.
Let us know how many it actually took for xx results when done. And let us know what actual load development system you eventually used to get r done.

 

[brantfredrickson]

Mike, Its modified OCW. But instead of using the groups you print on the target, you used the differences in velocity between powder charges. My results go like this:
between 39.6 and 39.8 is 21 fps difference
between 39.8 and 40.0 is 4 fps difference: 39.8 is the chosen charge
between 40.0 and 40.2 is 13 fps difference
between 40.2 and 40.4 is 17 fps difference.
In OCW you look at the groups, the smaller the group the closer the velocities. Same thing in 10 shot load development. I only have access to a 100 yard range and reading the smallest group many times is like reading tea leaves. If I had access to 300 to a 1000 yards I would do ladder style load development which is also bases on velocities.
As far as cost savings, there isn't any. I would shoot the same number of shots whether its OCW, 10 shot load development, or ladder load development. I've run 100 shots so far, and my do another 50 to dial in the seating depth further.
The application of 10 shot load development lends itself to 100 yards and to those with less than stellar shooting abilities. Its right for me, but not for everyone.

 

[seymour fish]

Not any confidence in this technique at all and the reasons are nearly too many to list. I am however interested to see if anyone can provide definitive evidence vs anecdotal "worked for me".

Charlie, Creighton Audette pointed out some correlation between nodes on a ladder test as seen on target and a flattening of the rising powder/velocity curve.