Ladder Test 105amax .6mmslr (.243)

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Ladder Test 105amax .6mmslr (.243)

Post by MalleeFarmer » 19 Aug 2016, 1:13 pm

Ok so I'm about to load up for a ladder test for my long range rifle. A quick question what increments would you load up would you start at minimum and work up in .2gr or .3gr increments? Or would you just do .5gr increments and spend more time working from the most accurate load.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Wm.Traynor » 19 Aug 2016, 1:22 pm

FWIW, I used to do 0.2gn for my 223 range rifle, so with your case capacity being greater, 0.3 should not be too much. BTW, bullets were maximum weight fo calibre, much like yours.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Gwion » 19 Aug 2016, 2:55 pm

I start either on lands or at max mag length. I then go 0.5gn increments from minimum charge to find a couple of approximate nodes with 3 round groups (usually 15 rounds or so total). I stop 0.5 below max and load just a few singles in 0.2 increments toward max load to test pressure signs for a future exploration limit (3 rounds). I then take my chosen 'best for purpose' (absolute most accurate for target but 'fastest' most accurate for hunting/varmint for a slightly flatter trajectory and longer MPB) and test immediately either side of that and 0.2gn up and down from there (end up with 4 x 5 round groups in 0.2gn increments). I then take the best of that test and load directly either side of it (10 shots). What ever is best from all these 3 rounds of testing, I then confirm with 3 x 5 round groups.

That's a total of around 60-70 rounds to complete initial testing and a nice day in the paddock. I then load up remaining cases (assuming you start with 100) and finish fire forming the batch while field testing.

After fire forming, I do a little exploration at the top end (as long as the first test loads showed no pressure signs) following a similar method. I also do some simple testing with seating 10thou in, 20thou in, etc.. This has been a successful method for me over a number of loads for both 223 and 7-08, producing a number of 1/2MOA loads or better.

Just what I do, if it helps.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 19 Aug 2016, 4:33 pm

I don't do a ladder test per se, primarily because I don't shoot precision rifles that have the required accuracy or the limited barrel life. I shoot five-shot groups in 0.5gn increments at 100 yards, measuring the velocities, the groups, and the group's mean elevation on the target.
When I worked up my 7mm-08 loads with the 100gn HP for varminting, I shot AR2206H from 41.5gn up to 45.5gns (ADI list 41.0 to 45.0). Velocities and group size went:
41.5gn (no velocity recorded) 1.25MoA,
42.0gn 3026fps 1.3MoA,
42.5gn 3058fps (+32fps) 1.0MoA,
43.0gn 3065fps (+07fps) 1.0MoA (cooled right down - clean-cold-barrel shoots 60-80fps slower than the second shot),
43.5gn 3108fps (+43fps) 0.7MoA,
44.0gn 3178fps (+70fps) 1.0MoA (hot barrel from previous group),
44.5gn 3212fps (+34fps) 0.7MoA,
45.0gn 3244fps (+32fps) 1.5MoA (starting to show pressure),
45.5gn 3264fps (+20fps) 1.5MoA (showing pressure).
The groups went from 5mm high to 45mm high, but from 42.5 to 44.0gn the vertical change in impact was only 10mm. So within that window is where this load shoots well in this rifle even across 120fps variation in velocity. For example, if I shot 25mm groups at 100 yards with loads of 42.5gn, 43.0gn, 43.5gn and 44.0gn, and then shot a group with one round from each of those loads, it'd still be a 35mm group, at least in elevation.

From that, I shot groups from 42.8gn to 43.6gn at 0.2gn increments and settled on 43.4gns as the most accurate.
I still need to test seating depths, but it's shooting well enough (0.5-0.7MoA is the norm off a bench) that I haven't gotten around to it yet. I'm about ready to do all this again as I'm switching all my loads across to benchmark 8208, I'm seeing more consistent velocity with it in the .204.

Although I might fire 100 rounds developing a load for a specific bullet, I don't consider any of that to be "wasted" or "burning out the barrel". Every round I fire is just more practise time :-)

I keep a shot log for every firearm too.
Last edited by bladeracer on 19 Aug 2016, 6:16 pm, edited 1 time in total.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by MalleeFarmer » 19 Aug 2016, 6:04 pm

Ok so I liked Gwions system so I'm going with that for now. Loaded up 12 starting from the minimum of 42gr or AR2213sc up to .5 below max at 43.5gr just have to wait till my pillars are back so I can finish bedding my rifle and my leg is sorted so I can start testing.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Strikey » 19 Aug 2016, 8:41 pm

I think first we need to define if you are doing load development as opposed to ladder testing which comes after load development and with your chosen cartridge would be worthwhile, there is a very good article on Accurate Shooter.com that explains the process, sorry I don't know how to link it. I prefer to shoot 5 shot groups working up •5 grain increments, with 3 shot groups operator error may confuse results whereas a 5 shot group should discount that. Once a node is found you work either side in •1 or • 2 increments then fiddle with seating depths, personally with this cartridge/ projectile combination I would test at 200yds, some of these long projectiles need that bit extra distance to settle and can group better than at 100yds, food for thought, have fun :thumbsup:
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 19 Aug 2016, 10:58 pm

Strikey wrote:I think first we need to define if you are doing load development as opposed to ladder testing which comes after load development and with your chosen cartridge would be worthwhile, there is a very good article on Accurate Shooter.com that explains the process, sorry I don't know how to link it. I prefer to shoot 5 shot groups working up •5 grain increments, with 3 shot groups operator error may confuse results whereas a 5 shot group should discount that. Once a node is found you work either side in •1 or • 2 increments then fiddle with seating depths, personally with this cartridge/ projectile combination I would test at 200yds, some of these long projectiles need that bit extra distance to settle and can group better than at 100yds, food for thought, have fun :thumbsup:



I don't follow. What would be the point of doing a ladder test after you've already developed a load? Any data you get is not much use if you aren't going to further develop your load to use it.
Agreed for hunting rifles, three shots doesn't tell you enough to warrant the cost of the ammo, five shots is more useful. Precision rifles though should be putting every shot into one hole so the original ladder test should work fine with single rounds. At 300 yards or more, not at close range, you need enough range to be able measure the elevation shift between shots.
I leave seating depth for last, after I've developed the load.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by MalleeFarmer » 20 Aug 2016, 9:10 am

A ladder test is purely the first steps of load development To find an initial accuracy node. Once you have found the most accurate initial load you can start varying .1-.2 either side to fine tune an accurate load. And from there pick the most accurate of these and then start adjusting seating depth. Because this is primarily a field rifle not a range or Comp rifle I'm starting on the lands and working back. As I cannot afford having a bullet stuck in the lands and then trying to extract unfired.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Gwion » 20 Aug 2016, 1:10 pm

As Strikey says, a ladder test is, strictly speaking, a range of charges fired in sequence to determine a 'window' that offers consistent elevation (read: velocity/low extreme spread). It needs to be shot at a distance that allows small changes in velocity to show up. Best performed with a chrony as back up.

http://www.6mmbr.com/laddertest.html

Most of us ameteur dumbarses tend to refer to any initial load development as a ladder test, though.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 20 Aug 2016, 2:32 pm

MalleeFarmer wrote:A ladder test is purely the first steps of load development To find an initial accuracy node. Once you have found the most accurate initial load you can start varying .1-.2 either side to fine tune an accurate load. And from there pick the most accurate of these and then start adjusting seating depth. Because this is primarily a field rifle not a range or Comp rifle I'm starting on the lands and working back. As I cannot afford having a bullet stuck in the lands and then trying to extract unfired.



Yes, a ladder test is a test to determine in what velocity range the rungs of the "ladder" are closest together, that's exactly how I do it, and is what I described. I use it to find that sweet spot where variations in my load have minimal effect on elevation, and thus the greatest accuracy at long ranges. That way I can expect other minor variations in my load or environmental conditions to also have minimal effects. Then I focus my load development within that zone and refine it for maximum accuracy. Then I play with seating depth to hone it further.

Strikey is saying the ladder test comes _after_ you've already developed a load - that makes no sense at all.

If you're doing this with a hunting rifle then you'll probably get better results by shooting five-shot groups and working to their mean points of impact rather than scew your results by using single shots, unless your rifle is shooting 0.2MoA or better of course. If you're shooting 0.5MoA, or 38mm groups at 300 yards and two bullets strike within 38mm of each other in elevation, how do you know if they're striking the same mean PoI or if the upper is in the bottom of its 0.5MoA ability and the lower in the top of it's? If you shoot groups then you can see if their mean PoI's fall on top of each other, or if you have two 38mm groups with a 38mm gap between them - then you have meaningful data you can work with.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 20 Aug 2016, 2:42 pm

Gwion wrote:As Strikey says, a ladder test is, strictly speaking, a range of charges fired in sequence to determine a 'window' that offers consistent elevation (read: velocity/low extreme spread). It needs to be shot at a distance that allows small changes in velocity to show up. Best performed with a chrony as back up.

http://www.6mmbr.com/laddertest.html

Most of us ameteur dumbarses tend to refer to any initial load development as a ladder test, though.



That seems to be exactly what I described...

"The groups went from 5mm high to 45mm high, but from 42.5 to 44.0gn the vertical change in impact was only 10mm. So within that window is where this load shoots well in this rifle even across 120fps variation in velocity. For example, if I shot 25mm groups at 100 yards with loads of 42.5gn, 43.0gn, 43.5gn and 44.0gn, and then shot a group with one round from each of those loads, it'd still be a 35mm group, at least in elevation."

I specifically don't use the term "ladder test" when referring to hunting rifle load development because then somebody is likely to Google it and waste their day shooting single shots from their 1.5MoA-capable rifle, and then almost certainly focusing their load development in the wrong place - that helps nobody. The strict one-shot ladder test is only useful for very, very, very accurate rifles and shooters.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Gwion » 20 Aug 2016, 4:40 pm

Was really just pointing out that my approach is not technically a ladder test, even if I some times refer to it as such.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 20 Aug 2016, 5:34 pm

Gwion wrote:Was really just pointing out that my approach is not technically a ladder test, even if I some times refer to it as such.



Understood, and I'm the same, as I stated before explaining what I do.
"I don't do a ladder test per se, primarily because I don't shoot precision rifles that have the required accuracy or the limited barrel life."

In practical terms it's a "ladder test" in as much as I'm looking for that elevation window, but it doesn't comply with the precision shooting definition so I never refer to it as such.

Strikey's comment is the only confusing thing which is why I mentioned it.
"...we need to define if you are doing load development as opposed to ladder testing which comes after load development..."
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Strikey » 20 Aug 2016, 6:21 pm

Bladeracer, as I stated in my post have a read of Accurate shooter, Gwion thank you for providing the link, I may not be totally comfortable with computers but I do know a little about extracting the best from reloads. Getting a little bit fed up with people arguing about something they don't understand, if what you are doing reloading works for you, Bladeracer, I'm happy for you, I will stay with what I do as I know I usually find good accuracy without burning a lot of consumables or barrel life and I was passing on some info for the OP that I assumed might be helpful without turning into a s**t fight :drinks:
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Re: Ladder Test 105amax .6mmslr (.243)

Post by MalleeFarmer » 20 Aug 2016, 6:30 pm

Can't we all just get along!!!! :friends: Thanks for the replies guys I did read that post from Accurate shooter a while back but you guys have only now explained correctly what a ladder test is. Cheers for that info. I should have just said load development in the title of the official post anyway when my rifle is all built I'll start getting to it then.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 20 Aug 2016, 6:41 pm

Strikey wrote:Bladeracer, as I stated in my post have a read of Accurate shooter, Gwion thank you for providing the link, I may not be totally comfortable with computers but I do know a little about extracting the best from reloads. Getting a little bit fed up with people arguing about something they don't understand, if what you are doing reloading works for you, Bladeracer, I'm happy for you, I will stay with what I do as I know I usually find good accuracy without burning a lot of consumables or barrel life and I was passing on some info for the OP that I assumed might be helpful without turning into a s**t fight :drinks:



There's no s**t fight on my part :-)
I don't understand what you posted so I mentioned it hoping you would explain what you said.
I don't see any difference between how both of us work up our loads, our methods seem to be identical.
But if you could explain why the ladder test is not part of load development, or how you could do a ladder test after developing a load I'd certainly appreciate it.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by bladeracer » 20 Aug 2016, 6:43 pm

MalleeFarmer wrote:Can't we all just get along!!!! :friends: Thanks for the replies guys I did read that post from Accurate shooter a while back but you guys have only now explained correctly what a ladder test is. Cheers for that info. I should have just said load development in the title of the official post anyway when my rifle is all built I'll start getting to it then.



No angst here :-)
Just endeavouring to make sure you are getting good, clear information you can use.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by MalleeFarmer » 20 Aug 2016, 7:33 pm

Can't we all just get along!!!! :friends: Thanks for the replies guys I did read that post from Accurate shooter a while back but you guys have only now explained correctly what a ladder test is. Cheers for that info. I should have just said load development in the title of the official post anyway when my rifle is all built I'll start getting to it then.
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Re: Ladder Test 105amax .6mmslr (.243)

Post by Norton » 25 Aug 2016, 11:09 am

MalleeFarmer wrote:Can't we all just get along!!!!


You do realise this is the internet, right? :mrgreen:
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