Ladder test - assistance interpreting results

[Miller Outdoors]

Could use some help from those who have more experience in these ladder tests than I have.

This morning I shot 2 ladders.

The first (left side of notebook sheet below) were 165 grain Gamekings using Varget. 17 shots starting with 43.0 grains spaced .2 grains apart up to 46.2 grains.

The second (right side of notebook sheet below) were 180 grain Gamekings using Varget. 13 shots starting with 43.0 grains spaced .2 grains apart up to 45.4 grains.

Wind was calm up until the 6th shot on the second ladder, then it started to get breezy, but I was selective in shooting while calmest. Shots were 4 to 8 minutes apart to allow barrel cooling. Shot 2 factory fowlers before first ladder. Temp about 70 and sunny. About 1,100 feet above sea level. The pinkish squares are 1 inch. Savage .308 22" barrel 1:10 twist shooting off lead sled. .02" off lands.

This is my notebook with the loads and chrony numbers.

This is the 165 grain ladder:

This is the 180 grain ladder:

What would you be looking to do next? I imagine I want to load up a few 3 shot groups and see what they look like, but what grains?

 

[midwesthunter]

Not to knock your test but all it shows is a one shot velocity which is kind of useless. Again don't take any offence to it. But you should do 3-5 shot groups all at same load. Measuring velocity for every round fired. Then when you have went up to the max load. You then take the and see what the extream spread in velocity per each group shot. Then you have to decide if the most acurate load has a good velocity spread. Or pick the one you think averages best of both

 

[Robbin]

I agree with midwest hunter, You should shot 3 shot groups for ladder tests. I only fire one shot when I'm looking for pressure signs, so I fire one, and climb until I get pressure signs then back down .3 from there and start a group ladder .2 apart going down, looking for nodes.

That said, you and your gun can shoot. Those where a 13 shot group and a 17 shot group, with each shot being a different powder charge and they looked to be just a little over an MOA! That's pretty impressive.

I don't think 2 fouler is enough. I've got several guns that don't settle down until the 5 th shot. Shoot 4 foulers if you are seriously testing.

I think you are going to be very happy with the way this turns out. Make sure you update this post, I'd like to know how the next set goes.

 

[squirrelduster]

I don't agree with your other two responders.
I always do ladder testing before loading up three round groups loads.
14, 15, and 16 on the left side have promise in my opinion. Pick a load in the middle and load up three and see what she does. I would bet with a little seating depth changes that load will shoot.
7, 8, and 9 on the right side shoot pretty well if the wind was an issue.
The way I do it is to look at the vertical and if it is reasonable you can tighten it up with seating depth changes.
I am not a bench rest shooter but one of the guys I shoot with occasionally is and has several national records to his credit. I have worked with him to refine my load workup skills.
Let us know how it goes with a few group pictures, it helps us all learn.

 

[justgoto]

With the 165gr, I would try loading 3 or so cartridges with 44.1gr to test after fouling shots... Also try 3 or so cartridges loaded at 45.7.

With the 180s I would try loading 3 or so cartridges at 43gr, (I just like those two shots,) then 3 or so cartridges at 44.5gr.

Here is a link for the people that are unsure as to what a ladder test is.


http://www.longrangehunting.com/forums/f17/audette-ladder-test-questions-42787/

 

[Miller Outdoors]

Thanks for the replies. Over the next few days I'm going to load up and fire some 4 shot groups and will post some photos when done.

 

[RockZ]

For the 165gr work around the 45.8 load.

For the 180gr work around the 3and 4 load and then the 10and 11load

the reason i suggest these is because they show good vertical
with better velocity than the 1and 2 load which also looks good

 

[J E Custom]

I also like the 3 shot each test with a target for each group (Results are easier to interpret)
and I put all the information,Load data,cartrige,rifle,Velocity,Standard deviation, Extreme
spread, conditions and yardage for later records if something looks good.

I find that poor records don't do any good after a while when your going over them to see
what they did with a different powder/bullet combination (Old Timers) and all the data.

I keep records of everything that has been done with the rifle/pistol in individual 3 ring binders
for each of my rifles/pistols and find it invaluable at a later date if accuracy starts to drop off.

It sounds like a lot of trouble but it saves time and money and if you go somewhere different
you can use the drop charts that were used years earlier once you verify your zero.

I have even carried the note book with me to refresh my mind with the performance under those
conditions ,Altitude,temp,humidity,wind effects ETC.

Good luck and good hunting

J E CUSTOM

 

[RockZ]

I also shoot 3shot groups for ladders with 3different loads
Just color the bullets with sharpies
I like blue green and red and shoot them round robin just
like in the sticky on ladder shooting

 

[Miller Outdoors]

I thought I'd update this with results.

After the ladder test and seeing your input I decided to load the following:

165gr Gamekings 2.830" OAL (.027 off lands)
1- 45.7gr = 2666 fps
2- 45.7gr = 2677 fps
3- 45.7gr = 2682 fps
4- 45.7gr = 2688 fps
100 yard group resulting from these shots: 1.037"

(I was also going to load up some at 44.1gr also, but ran out of Varget so I put it off. Glad I did because I've since decided to stick with the heavier .308 bullets)

180gr Gamekings 2.820" OAL (.027 off lands)
1- 43.1gr = 2510 fps
2- 43.1gr = 2506 fps
3- 43.1gr = 2515 fps
4- 43.1gr = 2510 fps
100 yard group resulting from these shots: 0.692"

5- 44.3gr = 2594 fps
6- 44.3gr = 2588 fps
7- 44.3gr = 2583 fps
8- 44.3gr = 2588 fps
100 yard group resulting from these shots: 0.650"

After looking at these results and plugging all velocity and ballistic coefficient info into dropcharts (shows heavier bullets have significant downrange advantages) I'm giving up on the 165gr bullets.

I then loaded up another set of the 44.3gr rounds with OAL's .02 longer and .02" shorter - the original 2.82" load outperformed both, so I'm sticking with the OAL of 2.82".

I took this ballistic data and printed off a dope chart and loaded up another 20 rounds. Took out the 10" metal gong target and shot at 300, 400, 500 and 600 and the dope chart is scary accurate up to the 600 yard max range that I shot it at.

So, I've got a good, accurate 180gr hunting load and long-range confidence.

Since the Berger Hunting VLD's have had good reports on game, and a bit higher BC than the Sierra Gamekings, I figured I'd work with some of the heavier VLD's. Did a similar ladder test and load workup with the 185gr Berger VLD's and have worked up an even more accurate load averaging 0.561" at 100 yards. I've ordered some 200 gr Gamekings and some 210gr Berger Hunting VLD's - when they get here I'll do a similar ladder test and load workup on both of those.

 

[Robbin]

Thanks for the update! Good shooting....

 

[RockZ]

Good job and good shooting.
It's nice when the process works and you get the results you are looking for.

Congrats!

 

[justgoto]

Great to hear you have good loads! Nice shooting too!