Input on reading a ladder test/final load

[David Christian]

If head and tail wind will produce vertical poi shift, does that mean if you have wind(say less than 3 mph) at 6 or 12 and there is very little(a bullet diameter or less) vertical the load is sweet? I only hunt and pd shoot so I tune for minimal vertical at 100 and 200 yards.

Run a few numbers through a ballistics app and see how small of a distance in drop a 6 or 12 oclock wind moves your bullet with a 10mph wind. Using all the same components as listed in the OP, and a speed of 2,820, my app shows the delta in drop between a 6 and 12 wind of .4 inches at 600 yards. Meaning you should not be thinking about changing your load due to wind conditions.

 

[Hermantk]

My experience suggests that
-you might want to try a few lighter loads as 2830+/_ seems to be where most folks have success with the 180s. It's always seductive to look for a higher MV that yields a node but in my experience, consistency rules and the node at around 2830 is stable. The next node is over 2900 and may present other issues associated with hot loads as well as less consistency.
-with h4350 you should be just fine at the temps you are running but come springtime as they rise to 70+, even though it is very temperature stable, you will want to verify. AND keep notes for future use.
-after you see what looks like a node you may wish to play with larger groups of 6 to 10 to confirm. The smaller steps like 0.2gr increments will show you the center of the MV range that gives you the node. I have even done 0.1gr
-I do my ladders at 300 meters and on days with 7-10mph tail or headwinds, I find that the nodes are still easily identified. On the odd occasion when i get to the range and things are very windy I might do my ladders at 200M and then validate at a later date at 300M.

 

[Hermantk]

in looking at the MVs, it seems to me that you might also want to look at your reloading practices as well. Your ESs are pretty wide for such small groups. Hard to get consistent elevation when your velocities are varying by 20 to 40 fps. You may actually have walked by a node at 50.5gr or 50.8gr

 

[Hermantk]

regarding the seating (jump/jam) question, I do find that on my barrels, the 180s like to jump. BUT, one thing at a time. You are doing a ladder test now for consistent elevation, and by far if not the only factor here (at 300 yards anyway) is MV which is about load far, far more than seating.

 

[roklock]

Thanks, going to search some lower powder charges on the next ladder.

 

[BIG D]

I see a node between 1-2. I’d start lower on powder charge around 49.5 and work to 51.? Read that ladder and I’d say you will land around load number one again from this ladder test. 50.5ish. Then test seating as ringostar suggested. Good luck.

 

[Hermantk]

I see a node between 1-2. I’d start lower on powder charge around 49.5 and work to 51.? Read that ladder and I’d say you will land around load number one again from this ladder test. 50.5ish. Then test seating as ringostar suggested. Good luck.

yup

 

[roklock]

Took the suggestions and over the past few weeks determined power charge and seating depth. Today I did a test using 1/10 powder increments to see what those results are. Loaded raw target and one with measurements, distance was 300 yards, temp ~50 degrees, light wind 2-5 mph, tail wind with a left to right movement.

I am leaning towards #3 as it is in the middle of the best verticals but I am open to suggestions and learning. Below are the numbers for each group as well. (avg mv, extreme spread, standard deviation)

1. 2847, 37, 15.5
2. 2852, 6, 3.5
3. 2838, 6, 3
4. 2836, 18, 8.5
5. 2841, 6, 3

Thanks...Steve

 

[David Christian]

Took the suggestions and over the past few weeks determined power charge and seating depth. Today I did a test using 1/10 powder increments to see what those results are. Loaded raw target and one with measurements, distance was 300 yards, temp ~50 degrees, light wind 2-5 mph, tail wind with a left to right movement.

I am leaning towards #3 as it is in the middle of the best verticals but I am open to suggestions and learning. Below are the numbers for each group as well. (Extreme spread, Standard Deviation)

1. 37, 15.5
2. 6, 3.5
3. 6, 3
4. 18, 8.5
5. 6, 3

Thanks...Steve

@roklock, did you gather your speed data for each group as well? I am most interested in seeing the speed increase over each powder increase. Thx
DC

 

[roklock]

@roklock, did you gather your speed data for each group as well? I am most interested in seeing the speed increase over each powder increase. Thx
DC

Hi David,

I edited my post adding the avg. MV to the data set.

 

[David Christian]

@roklock, here is a chart using Berger 180’s out of a 32”, straight 1.25” barrel. 5 shots per 1/10th increment. 50.7 through 51.0 only differ by 5fps. 2826 to 2831. The ES numbers per charge weight are low, which makes this type of chart easy to read.



you may still be a bit high on your powder charge, as your speeds are still fast.

DC

 

[roklock]

@roklock,

you may still be a bit high on your powder charge, as your speeds are still fast.

DC

What is leading this thought as my speeds are very similar on loads 3-5 with little variation. The same as in the chart.

something that is interesting are the loads. My test was done from 50.8 - to 51.2 using h4350

 

[Hermantk]

I wonder what would happen if you tested some slightly smaller loads to cover the velocity range between 2815 and 2835. I suggest this because with my 4 barrels, the nodes for my B180s and 184s are all between 2815 and 2830. And, at the risk of sounding like a smart-ass, the group at 2838 looks a bit big.

 

[roklock]

I wonder what would happen if you tested some slightly smaller loads to cover the velocity range between 2815 and 2835. I suggest this because with my 4 barrels, the nodes for my B180s and 184s are all between 2815 and 2830. And, at the risk of sounding like a smart-ass, the group at 2838 looks a bit big.

I definitely plan on it, I am not disagreeing with you or David, just want to understand my data better and the "why". I just realized it is hard to read my group sizes and posted them below. I do agree they aren't great and confusing as well since I got much better groups during seating depth testing. I had four different depths that ranged from .26 MOA to .20 MOA. (four shot groups)

These group sizes for the recent test above were as follows.

#1 - .68 MOA (2.14" in height)
#2 - .31 MOA (0.82" in height)
#3 - .49 MOA (0.72" in height)
#4 - .30 MOA (0.92" in height)
#1 - .64 MOA (2.00" in height)

 

[Hermantk]

Interesting discovery. I have been shooting Berger 180s and 184s with H4831SC and nodes in the 2815 to 2830 for all my barrels (1 serious competition and 3 others). Yesterday i started playing with RL-23. I have a clear node at 2795-2800 and nada in the 2810-2840 range. So i guess i gotta recant my earlier comment.

 

[Mulligan]

Interesting discovery. I have been shooting Berger 180s and 184s with H4831SC and nodes in the 2815 to 2830 for all my barrels (1 serious competition and 3 others). Yesterday i started playing with RL-23. I have a clear node at 2795-2800 and nada in the 2810-2840 range. So i guess i gotta recant my earlier comment.

In my rifle, the next node up is a dandy!
CW

 

[Hermantk]

will be looking for that one next week