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I performed a ladder test at 200 yd, found my nodes and now ready to advance to the next step of the processes, seating depth, but where to start?
I've searched the forum but only found vague references to the subject as it relates to "ladder test". Please enlighten me!
What seating depth did you do you ladder with? I seat close to the lands but I see a lot of guys seating way off the lands.
I do my seating at 0, 40, 80, 120 thousandths of an inch and go from there. I load up six of each and shoot two groups of each. I also do not shoot the same depth back to back to verify that groups accuracy.
The 155 grain Berger hybrids out of my 308 are screaming fast (3100 fps) and one jagged hole at 100 with 120 thou jump.
**** that is screamin...I do the same thing as you except the(.000 if im near max load)but I use smaller depth changes as .040 is a huge change...the factory barrel that was on my 300 liked anywhere from .025 to .085 depending on the bullet but both my 260 and 300 shilen barrels like the bullets close no matter what bullet. I shoot 220g and 210g smks and 208g hornadys in my 300 and 139g lapuas 142g smks and soon to try 140g hornadys in my 260.
I performed the ladder test with all bullets at .013 off lands. Don't ask how I came to that setting I just did. In the interest of full disclosure let me add that I am shooting a 110 w/ factory barrel chambered in 30-06. I found two nodes, one at the minimum (55 grains) and the other at 56.8 - 57. I'm going to use the rifle and loads for hunting and most anything would be ok but I have this belief that the bullet should go where you aim it not just in the general area.
In a hunting rifle I've read that it's advisable that the minimum seating depth (maximum cartridge length) is when you have one bullet diameter inside the case neck. Of course it also must fit and function in your magazine. There are as many techniques for testing as there are shooters to ask. To a benchrest shooter .010 is a big change, to a hunter .015 or .020 steps may be normal. You also may very well find "nodes" just like you do in the ladder tests. Find a technique that suits you and have a blast.
My factory 30-06 110 liked 57.5gns of IMR 4350 150sst hornady bullet seated at 3.25"oal. Mileage may very. I like JT an the others have said go 10thous at a time load 3 up of each and like the ladder test you'll see some nodes.
So I should abbandon the ladder technique and start shooting groups with varying seating depths?
I use the ladders to find the powder charges that your gun likes. This helps find the instances where the barrel is most accurate. I further fine tune these accuracy nodes with seating depths. If I'm starting a new barrel I typically jump them 40 thou for the ladder. Many times having them jammed pressures are higher and I have wound up with slower loads due to it.Quote:
Originally Posted by olddav
No. Ladders are a quicker way to find nodes (frequencies) that give us the best grouping for the powder/bullet chosen for a given barrel. Seating is fine-tuning that "best" node further (albeit you may have some difficulty in distinguishing changes). You want to make changes in seating depth in 0.010 - 0.015 increments and larger samplings. Do this in calm conditions so as to avoid having conditions influence your results. Typically most rifles will shoot their best groups with the bullet just touching the lands. This is where I test for nodes (and where the pressure will be at max for a given charge). Then you can take your seating die and say 20-30 rounds of the load you found in your ladder test, and shoot 5 rounds each at each increment (seating the bullet slightly more for each group fired). This will also decrease pressure slightly, so go back and repeat using 0.1 and 0.2 grains more powder. Now compare all the data and you should find your best load there.Quote:
Originally Posted by olddav
For me, I do not screw around with seating (my only rifle that has a seating with jump is my .308 Win). I like the bullet touching the lands as I can make slight adjustments as the leade becomes a bit longer as the throat wears down due to the heat and wear from use. That too will change pressure (slightly lower) and a change in the powder/charge may well be in order later on down the road.
First let me ask what are you trying to do with this riffle? Hunting? Target benchrest? Flame suit on...IMHO I dont think ladders, ocw, round robbin orr any of those type of tests work for an average shooter they are ment more for benchrest guys that know their equipment and shoot off of NICE bags or lock the riffle down to eliminate as much shooter error as possible. I shot two ladders when I first started reloading and they told me nothing.
I start my loads just a little above the middle of what the book says and work up in .5g increments to max book load and shoot 3 shot groups with all bullets seated .005 off the lands...I seat .005 to start because it tells me two things right away,1 if the bullets like being close and 2 if I have pressure at or near max loads. Starting with the bullets seated deep is a pain because now your not sure which way to go and if at or near max load going closer may cause pressure issuses so now you start over and accuracy isnt about velocity....I can and have shot 210g smks out of my 300wm at 3075fps but its all over the target...every bullet ive shot has liked being closer to the lands and between 2700 and 2900fps....the factory barrel on my 300 liked .025 but I stumbled on that seating depth and never played with it.
If you think you found a couple of good nodes with the ladders load up 3 each at .006 and .020 and shoot them at 200yds and thats going to tell you right away if its a good node and if the bullet wants to be closer or farther away.
I will be hunting with this rifle and I do not expect that in the end it will shoot like a bench rifle, but the ladder test is one way to develop loads. Learning a different method to develop load seems like something that is well worth my time and effort.
Anyway I performed the ladder test using bags a both the front (forearm) and back (butt stock) of the rifle. I assumed that it is important to have a consistent aim point at 200 yards otherwise the ladder test would yield no usefull information. Considering that the nodes vertical spread (from ladder test) is .250" it occurred to me that continuing with the ladder method to determine the seating depth would be problematic. In addition I don't know how much of a spread (seating depth) is desirable between loads.
Thanks for everyones input. I am reading each post carefully and trying to absorb as much valuable info as I can, as this place is a wealth of valuable info!
If its a hunting riffle all shots should be fired from a cold bore especially from a factory barrel because as it heats up it will most likely change the point of impact. I would load up 3 rounds at the nodes you found at .013 since that is where you started and shoot 1 round then let the barrel cool then shoot the next round at the same point of aim and repeat until you have shot your first 3 at the same target then do the same with the next 3 at a new target and see how they group and then go from there.
When I shoot a ladder test I try to shoot 500 yards. I shoot 1 round with lowest powder charge and (for me) increase the charge .5 grs. untail I reach max load. I also seat the bullet to touch the lands in this test as this is where max pressure will be. I am looking for one thing - closest vertical group of shots with a wide range of powder charges. There is usually 2 of these groups. For me this tells me how the harmonics of my barrel are working with a wider range of powder charges. My 260 right now shows a group of 5 shots less than 2" with powder charges from 39.5 to 41.5.
Then you are shooting the ladders as they were ment to be shot and will have much better luck with them than most....this is another big problem with ladders and all the other charge tests that most ppl miss when researching them...they are ment to be shot at 500yds not 100 or 200yds.
I did catch that but you got to go with what ya got. Even though I shot at 200 yards it did produce what appeared to be useful information. The two nodes were quite clear as compared to the other shots.
My last post was not directed at you or ment in a disrespectful way it was just a general statement...like I said if you found nodes shoot them at 200yds and see how they group.
This is why I hate to communicate via text, it is just too easy to misunderstand one another. I did not take exception to your post and I hope you didn't take exception to mine. I just want to get the most accurate info possible.
No not at all ive got thick skin and dont take offense to much but I do think I come off that way at times...ive been a roofer for coming up on 31yrs and have been the superintendent at one of the largest shops in northern nevada for 10 of those years so im a little more straight forward than most ppl like.
Shoot your nodes and you may be surprised.
roger that...Quote:
Originally Posted by JTCrl
I find my powder load via ladder. Depth I start with jam and back off .005 with 4-5 different depths. It will be revealed to you
Finally got around to trying the second half of load development. I loaded a total of 15 rounds (5 sets of 3), started with a COL of 3.258", followed by, 3.245", 3.235", 3.225", and finished with 3.215". Shot each set at 200 yards with bags supporting the rifle both front and back and I let the barrel cool between sets. The best group was produced by the bullets seated futherest from the lands, sub MOA (1 5/8"). It might produce a tighter group but I had some hortizional stringing.
I think if I need to develop a load again I'm going to use the ladder test. Two sessions and I'm done, close enough for a hunting rifle.
I tried a ladder at 300 yrds and it was worthless. 500 is really the ticket. I just need to find a place near where I moved to shoot 500.
If your limited on distance I would really try the ocw method.
At 200 yrds grouping issues mess up the test. Unless you can shoot it 3-5 times and come up with the same nodes.
But yes seating test would be next in two nodes and find which one comes out on top
Okay you guys are saying 100 and 200 yards are not correct for a ladder test and that 500 is the intended range for a ladder, but why is 500 the intended range. This is just me thinking and talking/typing but 500 yards gives a whole lot more time for things like wind no matter how slight to effect groups. #2 500 yards is a hell of a distance for someone looking for an accurate hunting load although some regularly hunt at that distance out west and such sub 200 yards shots are probably more the norm and where i would want my accuracy. So educate this shooter trust me it wouldn't be the first time a discussion on this forum changed my mind on a topic!
Ladder tests can be done at any range. Longer ranges may make identifying the nodes easier but, as mentioned above, must be done under "perfect" conditions to be valid. If you can get those conditions then doing your ladder tests at the range you do most of your shooting at makes the most sense. Even at 200 yards a "light and variable" wind can compromise your results.
I have heard veteran benchrest shooters say they minimize the vertical component in their groups via the ladder test then minimize the horizontal component with seating depth. Never found it to be quite that simple myself but, once you have established a seating depth your rifle likes, you have a better starting point for your next ladder test. And the next, and the next, and on it goes.
Yes, you do need to start over with a new ladder test every time you change a component. A 52gn Berger may not like the same recipe as a 52gn Barts in the same rifle. When switching from a Winchester primer to a Remington primer I've found I need a 1% increase in the powder charge to achieve the same velocity though not necessarily the same results. Lake City brass has a slightly greater case capacity than Lapua brass.
I have not found seating depth to be a very valuable tool when trying to shrink 1 1/2" groups to 1" in a hunting rifle, more valuable when trying to shrink .3" groups to .2" groups in a target rifle. Of course target rifles have the advantage of not being limited by magazine length or the need to seat bullets deep enough in the case neck to keep them secure under hunting conditions.
Just my personal experience, your mileage may vary:usa2:
It's because 100 or 200yds is not enough distance to open up the groups enough to see a definite difference in the nodes. 300yds will work for a ladder test, but like the guys that can shoot 500yds are telling you, it's a lot easier to see the differences at that distance.
Okay I am tracking I was thinking there was something at 500 yards that rounds would do differently then at 100/200. Basically it is just easier to see the difference in .5 MOA and 1 MOA at 500 yards then it is at 100 yards. My new way of doing my ladders now is to load my steps and head down to the 100 yard indoor range I found 45 min away from the house shoot them there and get new nodes for several weapons then head to a range that is an hour and half away after a few trips shooting ladders at the indoor and shoot them at 200 yards although I am looking forward to working that out farther.
Just to add to the decussion, the nodes I found at 200 were pronounced, perhaps it was a fluke. Admitted I am shooting a hunting rifle with a thin barrel and I was only able to achive a sub MOA group at 200 yards with two trips to the range, good enough for hunting. If I was shooting a target rifle (capable of one ragged hole) I would suspect that at 200 yards I would experience a whiteout if you will, (too many holes in too small an area) and would need 500 yards to separate the shots.
When I shoot a ladder I load a series of 12 loads, 2 rounds of each load. For a 223 loads are generally in .2gn increments. You can use whatever number of loads, group sizes, and increments fit your purpose.
The 12 2-shot groups are each fired at an individual target. A group of six targets fits on one 8.5x11" sheet of cardstock.
http://accurateshooter.net/targets/TargetC.pdf
Measure the distance from the bottom of the target to each hole, plot them on a graph, your nodes will appear.
Edit: Apparently I need to figure out how to insert a picture!:rant:
You cant do seating first I've tried.
The seating depth will vary with load.
For instance my creedmoor would shoot hole for hole but with extreme fliers kissing the lands at 43.5 gr.
Backed off to 42 and .01 off shot best.
Back down to 41.2 and it was like .03
The lighter the load the more of a running start it needed to engage the rifling and stabilize.
But granted they are all in the same ballpark but still affects short range grouping
In general I haven't had much success starting with seating depth first either with the exception of some Berger 115's in a 25-06. Two ladder tests and an OCW test with this known accurate rifle were disastrous. Called Berger and they clued me in to their 0.040" seating depth test to establish the proper range. At 0.080 off the lands the rifle was back to it's old tack driving self again. From there I did the ladder and then fine tuned depth afterwards like normal so it wasn't completely a matter finding the depth first but getting in the right ballpark before starting on charge was crucial to getting that bullet to work.Quote:
Originally Posted by limige
Good to know! Still trying to perfect a process