140 Accbond Ladder test

Bruce Mc

Bruce Mc

Handloader
Oct 26, 2005
1,165
376
Sunday afternoon, the wife is out of town with her buddies, no football on that I care to watch, what to do? Ahh, that ladder test I've been threatening myself to try. So out come the reloading stuff, 140 AccuBond, reloder 26, and some winchester cases.

3.340 OAL Federal 210 primers

59.3 grs 3002 fps
59.6 grs 3006 fps
59.9 grs 3023 fps
60.2 grs 3044 fps
60.5 grs 3103 fps
60.8 grs 3088 fps
61.1 grs 3140 fps
61.4 grs 3133 fps

I had originally planned on firing off ten rounds starting with 59.3 and ending with 62.0 grs. According to the quick load 62 grs. was supposed to yield 3120 fps. at 64000 psi. I figured the pressure must be getting close to max. so I stopped. What do y'all think?

Geez, I forgot to mention its a .270 winchester.
 
New to forum....but hello! I had read some on the ladder test here, and finding the "node", then drop halfway to begin the fine tuning, then primers..seating depth..etc..
Would you help me understand where the "node" is in your results; and any other info on this subject your willing to share with me?
 
my model 70 has a 22 inch barrel. I've also weighted my cases and checked the case capacity since I posted. The bag of winchester brass is some of the most consistent I've ever seen from winchester. The ten pieces of brass I used weighted an average of 191.38 grs. with a sd of .622. The case weight full of water worked out to 261.38 grs with a sd of .701. Thats a usable capacity of 70 grs. I weighted the cases full of water after I fired them in this test. Perhaps someone with quickload could give this a run through.
Rugerfan, I've never done a ladder test. I was hoping on some input from the crowd here.
 
60.5 to 61.4 isn’t horrible at all. I’d almost be inclined to try a few higher if you don’t have any psi signs. Mine really started looking excellent right at the top end. I believe I’m running 60-61 with the 150 ABLR.

59.3-59.6 doesn’t look horrible either but that spot above looks pretty broad.
 
And I’d also use .2 of a grain in the future. Gets hard to see the spots with that amount of spread.
 
Scotty, I'm starting to get a rough edge on the primer strike and primer is flattened but still has a little radius on the edge. It's getting close.
 
Bruce,

Here is Quick Load projection for you. I used an overflow case capacity of 70 gr. of water. To come close to matching your velocities with that case capacity I increased the Ba factor from .3397 to .3590. The Quick Load velocity projections are more linear than your data so it doesn't match at all charge weights.

For what it is worth, the OBT for node 5 for a 22" barrel is 1.127 ms, which according to this projection, would be at about 59.5 grains.

Dan

Useable Case Capaci: 62.396 grain H2O = 4.051 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Alliant Reloder-26 ?

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.82% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-08.2 91 56.00 2815 2464 45491 13210 99.7 1.243
-07.4 91 56.50 2842 2511 46876 13282 99.8 1.226
-06.6 92 57.00 2869 2558 48308 13348 99.9 1.209
-05.7 93 57.50 2895 2606 49790 13407 100.0 1.192
-04.9 94 58.00 2922 2654 51323 13460 100.0 1.176
-04.1 95 58.50 2948 2703 52904 13507 100.0 1.159
-03.3 95 59.00 2975 2751 54546 13552 100.0 1.143
-02.5 96 59.50 3001 2800 56235 13597 100.0 1.128 ! Near Maximum !
-01.6 97 60.00 3027 2849 57973 13641 100.0 1.112 ! Near Maximum !
-00.8 98 60.50 3053 2898 59763 13684 100.0 1.097 ! Near Maximum !
+00.0 99 61.00 3079 2947 61609 13726 100.0 1.082 ! Near Maximum !
+00.8 99 61.50 3105 2997 63515 13768 100.0 1.067 ! Near Maximum !
+01.6 100 62.00 3131 3047 65482 13809 100.0 1.053 !DANGEROUS LOAD-DO NOT USE!
+02.5 101 62.50 3156 3097 67512 13848 100.0 1.039 !DANGEROUS LOAD-DO NOT USE!
+03.3 102 63.00 3182 3148 69609 13887 100.0 1.025 !DANGEROUS LOAD-DO NOT USE!
+04.1 103 63.50 3208 3198 71774 13925 100.0 1.011 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 99 61.00 3212 3208 77219 13168 100.0 0.989 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 99 61.00 2873 2566 47372 14169 98.1 1.208
 
Thank you Dan, it'll take while for me to digest all of the data.
 
rugerfan":2h984ebi said:
New to forum....but hello! I had read some on the ladder test here, and finding the "node", then drop halfway to begin the fine tuning, then primers..seating depth..etc..
Would you help me understand where the "node" is in your results; and any other info on this subject your willing to share with me?
Click to expand...

That's a good question, I think I understand it maybe someone can confirm it. It looks like you are looking for speeds that don't jump up sharply but are pretty stable.

SJB358":2h984ebi said:
And I’d also use .2 of a grain in the future. Gets hard to see the spots with that amount of spread.
Click to expand...

Would you go with 0.2 with the 358 Win as well? I'm going to try that out tomorrow and see what it is all about.
 
rugerfan":h4oqyqfi said:
New to forum....but hello! I had read some on the ladder test here, and finding the "node", then drop halfway to begin the fine tuning, then primers..seating depth..etc..
Would you help me understand where the "node" is in your results; and any other info on this subject your willing to share with me?
Click to expand...

Rugerfan, welcome to the forum. There is a lot of good information here.

I am a relative newcomer with only 3-4 years as a member. There are many members here who are much more experienced and much more knowledgeable than I am. I thought I knew something before I joined. Now I feel that I am a novice compared to some of the others. During the day on Sunday is usually a pretty slow time on the forum. Many members are busy with their families.

As others did for me, I will try to point you in the right direction. I would encourage you to "google" the terms "Optimum Charge Weight" (OCW), "Optimum Barrel Time" (OBT) and "Ladder System" or Audette System"

I think that in the context of a ladder test, a shooter is looking for an range of charge weights where the velocity doesn't change much with the powder charge. This range of charge weights constitutes a "node". If you are in the middle of this "node" you will have more uniform velocities and hence more consistent impacts on the target.

Here is a link on the concept of Optimum Charge Weight. This is an empirical method of finding an accurate load:

http://optimalchargeweight.embarqspace. ... 4529817134

Here is a link describing the difference between the ladder test and the OCW:

http://optimalchargeweight.embarqspace. ... 4529811360

In the context of Optimum Barrel Time, a "node" is when the bullet exits the barrel at an optimum time for best accuracy. Here are a couple of links describing the theory:

http://www.the-long-family.com/optimal% ... 20time.htm

http://www.the-long-family.com/OBT_paper.htm

Mr. Long's writing describe how he believes these concepts merge. He believes the program "QuickLOAD" can be used as a tool to predict the OBT and hence the OCW.

I hope this information is helpful.

Dan
 
I even did a test of my own on QL and got the same exact match as Dan's. Node is where Dan said it is, at 59.5 grains, which is the fastest node, the slower node would be at 57.2 grains which is too slow. I see a flat spot between round #1 and #2 on the ladder test and a drop in velocity on the last round, it may be an indication you getting to max. You may want to load up some 3 round groups of 59.2, 59.4 and 59.6 grains and check them out again. Good luck and keep us posted.
 
I'm with Scotty.
60.5-60.8 looks good maybe even to 61.4 but you mentioned that may be a little warm.
I'd try some at 60.6 or thereabouts and I'd bet you'll be good. May have to monkey with seating depth a hair but bet it'll shoot. :grin:
 
gerry":20s3p2kn said:
rugerfan":20s3p2kn said:
New to forum....but hello! I had read some on the ladder test here, and finding the "node", then drop halfway to begin the fine tuning, then primers..seating depth..etc..
Would you help me understand where the "node" is in your results; and any other info on this subject your willing to share with me?
Click to expand...

That's a good question, I think I understand it maybe someone can confirm it. It looks like you are looking for speeds that don't jump up sharply but are pretty stable.

SJB358":20s3p2kn said:
And I’d also use .2 of a grain in the future. Gets hard to see the spots with that amount of spread.
Click to expand...

Would you go with 0.2 with the 358 Win as well? I'm going to try that out tomorrow and see what it is all about.
Click to expand...

Yes sir. .2 should work fine. Easier to see the spots. I used .1 on a 22-250 I was fine tuning. Worked like a champ.
 
I wish to send a big thanks to EVERYONE who shared info regarding OCW, OBT, Ladder system, etc. This was EXACTLY the type of info I was searching for.
I am just a basic reloader who has reached a point of realizing just how much I don't know and also when looking into "new" theories, am finding there often times seems to be counter theories.
Again, thanks to all, I am off to do some research now.
 
NYDAN":1dfg0ujm said:
rugerfan":1dfg0ujm said:
New to forum....but hello! I had read some on the ladder test here, and finding the "node", then drop halfway to begin the fine tuning, then primers..seating depth..etc..
Would you help me understand where the "node" is in your results; and any other info on this subject your willing to share with me?
Click to expand...

Rugerfan, welcome to the forum. There is a lot of good information here.

I am a relative newcomer with only 3-4 years as a member. There are many members here who are much more experienced and much more knowledgeable than I am. I thought I knew something before I joined. Now I feel that I am a novice compared to some of the others. During the day on Sunday is usually a pretty slow time on the forum. Many members are busy with their families.

As others did for me, I will try to point you in the right direction. I would encourage you to "google" the terms "Optimum Charge Weight" (OCW), "Optimum Barrel Time" (OBT) and "Ladder System" or Audette System"

I think that in the context of a ladder test, a shooter is looking for an range of charge weights where the velocity doesn't change much with the powder charge. This range of charge weights constitutes a "node". If you are in the middle of this "node" you will have more uniform velocities and hence more consistent impacts on the target.

Here is a link on the concept of Optimum Charge Weight. This is an empirical method of finding an accurate load:

http://optimalchargeweight.embarqspace. ... 4529817134

Here is a link describing the difference between the ladder test and the OCW:

http://optimalchargeweight.embarqspace. ... 4529811360

In the context of Optimum Barrel Time, a "node" is when the bullet exits the barrel at an optimum time for best accuracy. Here are a couple of links describing the theory:

http://www.the-long-family.com/optimal% ... 20time.htm

http://www.the-long-family.com/OBT_paper.htm

Mr. Long's writing describe how he believes these concepts merge. He believes the program "QuickLOAD" can be used as a tool to predict the OBT and hence the OCW.

I hope this information is helpful.

Dan
Click to expand...
 
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