155 palma and ladder

Niko-PG

Niko-PG

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So today I went to try out the new (to me) 155gr palma for my 700 PSS.
I decided to use the ladder method to find my best load and it was a disaster !
I had my loads starting at 44gr up to 46.2gr (NATO brass) by 0.2 increment.
Weather was cold but no wind.
Range was 200 yards and I used one target.

Problem: instead of having a nice string of holes going up then cluster, I had holes all over the place! For example 44.6 will hit a 6 o'clock but 44.8 will be way up at 12, then 45 will be dead center... I end up with a cluster but made of random loads. Some hits were even 3 or 9 o'clock !!

because I'm ready to blame the shooter, I had another set ready to go with the exact same loads. I was expecting to have the same target but nope, something again completely different, with holes all over !

Just to check I shot 0.80" 95 rounds) at the same distance with 168gr and my trusted load.

So what's going on ??? :confused:
The 155 doesn't like to be jumped? OAL is 2.8 for now as I'd like to find a load before playing with length.
I see a lot of recipes exceeding the 47gr max recommended, is that the secret ?
any idea?
Thanks
 
Niko-PG said:
Problem: instead of having a nice string of holes going up then cluster, I had holes all over the place!
Click to expand...

I wouldn't think they would all fall on a vertical line. My load testing using Mysticplayer's 2 shot test method has shown significant variations in POI between fairly small variations in charge weight, with the variations occurring both in the vertical and horizontal. The groups also clock all over the place as I come into a node and then move away from it.

If I understand the ladder test method correctly, you ignore the windage and concentrate on the elevation to find your nodes. Since I have never worked at it, that could be completely wrong, though.

Mark
 
mmattockx said:
If I understand the ladder test method correctly, you ignore the windage and concentrate on the elevation to find your nodes. Since I have never worked at it, that could be completely wrong, though.

Mark
Click to expand...

That's my understanding as well. What I did was put a 2in X 3.5in flourescent green appointment card from my dentist in the middle of a piece of plain cardboard about 2 feet square, adjusted my scope so the fouler shots (which were loaded to the same weight as the beginning charge on my ladder test) hit towards the bottom of the cardboard when aiming at the green card, and carried on from there, always aiming at the green card.
If shooting off bags, were they supporting the stock in the same place each time?
fwiw, I seated my SMK 155's and my Amax 155's 10 thou off the lands. I use 47gr varget and Lapua brass.
 
While some guys are proponents of the ladder method, I don't use it myself. I like to shoot 3 shot groups utilizing comparison to POA. I have more detailed results and it is easier to understand for me. As for your current dilemma I would recommend that you take a pic of your target and id which holes went in what order and maybe somebody here can help you out.
 
First of all, if Ladder testing, use a proper ladder test target This type of target eliminates the problem of what bullet corresponded with what load.

It is really important to establish a good empiracle seating depth prior to testing and I would suggest getting the bullets as close to the lands as you can.

If you are a shooter that still struggles with precision, a ladder test is a dubious method. You may simply be better off shooting 3-shot groups and use increments of .3 grains.

There should be a clear trend towards a better group, followed by a trend towards them opening up as you leave the node. One really good group between two really crappy groups would make me suspicious. I would keep working.

Not all guns like all bullets, and not all cartridges like all powders. The fact that you can shoot accurately and with precision using 168's is comforting, because you have a basis for comparison, but keep at it. Depending on which palma bullet you are using, they can be very accurate long range projectiles.
 
Obtunded hit it pretty much on the head... I really don't like the ladder method as I find it too hard to figure out if what I am reading with only one shot is good enough. I say this because once I find a good load, I go into mass production and start shooting that load. I think it saves time as I almost never have to play with OAL unless the rifle is really finicky - but I am the type that is pretty happy with .25-.50 MOA as I am not a benchrest shooter.
 
200 yards is too short a distance to get any usefull information from. 300 is the bare minimum I would suggest for a ladder test with something longer prefered. I do my testing at 600.

However, your results sound consitent with what I have seen on target. The bullets do not always "climb the ladder" in a nice even pattern. Sometimes they jump all over the place. Sometimes they go down instead of up.

I try to ignore the windage and focus on the actual drop. If there are multiple nodes that look good, I will then use the windage to weigh in which one shows more potential.

I am far from an expert on the topic, but this is my method:

Part VIII - The Ladder Test Procedure
[youtube]c5SmiMSF20A[/youtube]

FYI, my latest load developed using this procedure :
.308WIN 155Gr Lapua Scenar @ 2.800 COL
Remmy brass, CCI BR2, 46.4 Gr Varget, 2850 FPS
 
The Sierra 155's do like to be jumped, about .020 to .050" in most cases. Ladder tests should never be done anywhere closer than 500 yards with 600 being optimum IMO. What powder are you using? There has been a lot of success with Varget, Re-15, and 4895. Another tip is to color the tips of the bullets, NOT THE OGIVE or BS, with different color sharpie markers and use a white target so the bullet actually colors the target as it passes through. So you could use red, green, blue and keep alternating for every increment. No real special target necessary as long as it will clearly show color differences, cardboard may work as well. If you want to see how it should work, you might be able to try it with your 168's and then you should see 3 of them group close to where your pet load is now.
 
ryan: Great video, I would like to point out that he basically used the 3 rd group method to cfm his work - I basically use that same portion to do my load development. Not to knock the ladder method however I think it is just plain easier to see with the 3rd group method clear results - it takes the guess work out of load development...
 
Thanks!

I prefer that all my rounds fit the magazine, so I don't play much with seating depth.

I have used the above method to develope many different load combinations. I have it down well enough that I can find the optimal node for a given bullet/powder combination within 50 rounds. I doubt that any other load developement method will give such solid results with so few rounds down the tube.

So far, it has not failed me or my shooting buddies who have also tried it. Its the whole reason I made the video...to spread the good word, and help save bullets/barrel, for better uses.
 
I understand the longer range but in my case it would have been just a bigger messy target :rolleyes:.

Looks like I'm back at 5 rounds group testing.
Barrel is 1/12 so it should be ok.

Thanks for you help
 
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