?? Ladder test or whatever you call it..

[acemisser]

Can someone please take the time to explain this Ladder thig to me.

I guess my head is too think or the plate has shifted,cause I just cannot
get a grip on it...Is it done with only one brand of bullet?
Do you keep the same over all length,etc?
Thank you so much for the information...Ace

[M.O.A.]

yes i would like a step by step on this to because i just cant wrap my head around this ethere

[acemisser]

optimalchargeweight.embarqspace.com/ocw-vs-ladder/4529811360 - Cached

this is a good read..

[nsaqam]

Here's a good article on the Audette Ladder Test method.

http://www.mikeswillowlake.com/the_ladder_test.htm

[devildogandboy]

you may want to read this article also.

http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134

[skypilot]

The shooter and rifle must be capable of consistentcy.
1 Pick a powder and bullet
2 Check data for that powder and load, for example, minimum 30gr IMRxxxx, max is 35 gr IMR xxxx for a 120 gr hpbt
3 Reduce max load 6-7%. For the ex. above 35x.07% = 2.45 gr then 35 - 2.45=32.55 or 32.6 gr. This is the starting load.
4. If above .223 Rem caliber go in increments of .3 gr if not use .2 gr. Example 32.6, 32.9, 33.2, 33.5, 33.8, 34,1, 34.4, 34.7, 35.0, 35.3. Load 3 shells of each increment and a normal overall length say for ex. 2.710" per load manual length data.
5 Label the cases with a perma marker #1=32.6, #2=32.9, #3=33.2, #4 33.5, #5 33.8, #6 34.2, #7 34.5 etc., etc, in case you spill the box of cartridges.
6 Set up at the range at a minimum of 200 yds(300 is better). Set up a large target specifically in vertical height and shoot 1 round of #1 and record on a spare target where it hit. Then shoot 1 round #2 and mark it's placement on the spare target also. Continue until this round robin is complete or until you see pressure signs.
7. do not pay attention to horizontal stringing(that can be the wind. What you are looking for is a vertical stringing of rounds(that's why we put a large vertical target)then a cluster/group close together and then vertical stringing again and then a pressure sign to stop(flat primers, sticky bolt and lift)
8 Where the cluster came together for example #5,#6, and #7 clustered then #8, 9 started vertical again and #10 showed a sticky bolt and flat primer. etc
9 Now we know the accuracy node around #5,6,7 that is closer to max pressure is where we need to focus.
10 Take say, #6(the 34.2 load)and play with the seating depth and load 5 rounds of that seating depth and 34.2 gr powder. Maybe even try .1 grain above and below the 34.2 gr to really tune the load.
11 Confirm that this load groups at that seating depth. And continue to tune seating depth until it is as good as it will get considering your rifle setup and barrel harmonics and pressure waves.

[groaner71]

Thanks for the explanation. Easy to understand!:)

[M.O.A.]

yes thanks now i know

[acemisser]

I'm down now....Awesome Got it Dude thanks lol

[CharlieNC]

While the main point which you read about is minimizing the movement vertically, I have found that the horizontal deflection often correlates as well. Think about it, do you think barrel vibration is only happening perfectly in the vertical direction? When you change loads do you ever see a clear shift horizontally? So another way to judge the results is to measure the distance between impact points. I prefer to measure both the V and H distances from point of aim, and then calculate the distance vector. In this way you can identify loads that minimize distances between shots, which is group size. Maybe I will write this up with an excel program example latter; yes I'm a techno-nerd!

[groaner71]

More food for thought... :rolleyes:

[DPmax]

If you have the ability do two ladders 300+ yards apart, the second/furthest ladder is done based off the first for fine tuning.
Do as Skypilot wrote for the first/closest ladder.
Then load/shoot smaller powder steps between just your "accuracy node" from the first ladder for your second/further ladder (5,6,7 in the example), include three seating depths with each powder load... shorter, same, longer than the original depth used in ladder one.
I looked all over for a chart I once saw but could not find it, the chart laid out a two ladder (two days if you can't reload in the field) method using 20 total rounds, I've done it with my 110BA in 338LM and it works great!

[DPmax]

(dupe)