Ladder test.

[ian45662]

I am going to conduct a ladder test on Wednesday. I am going to start with a load that uses 0 compression and increase the charge on each shot by .2 grains until I get to about .300 compression. I will use my shot camera to keep track of each shot. Somewhere I am hoping that there will be 3,4 maybe 5 shots ,in succession ,that are going to be really close to each other. That is where I will start my 10 shot tests. Does this sound right? Is this how others are doing their ladder tests?

[martinibelgian]

.2 grains is way too little difference for a 1st test, I would do a 1st range with .5 grains difference. When ID'ing potential nodes, you can always revisit later with a smaller difference.
Goal is to ID points where accuracy remains good with a difference in load. .5 grains won't make a big change in MV.

[bpcrshooter62]

I agree i start to test at half a grain increases and then fine tune it from there saves on primers and powder butt i shoot 5 shots of each to find the nods

[martinibelgian]

I agree i start to test at half a grain increases and then fine tune it from there saves on primers and powder butt i shoot 5 shots of each to find the nods

Now, then it wouldn't be a ladder test...

[bpcrshooter62]

Well it works for me lol do you put your gun in a vise ? I dont trust one shot differences things change or maybe not every shot so to me 5 is better than 1 to determine the best places to start to each there own lol Keep shooting and having fun

[Clarence]

I've had pretty good results from single shots in 0.5 grain increments, picking the middle of a node where several shots are close vertically and then testing that node with 5 & 10 shot groups, ala Rick Moritz. Good chance of finding a good load in 25 rounds or so, instead of 50-?? rounds.

Clarence

[desert deuce]

Well Ian, since it is you. Deana thinks you are special, you know?

Anyway, If I were starting with Swiss 1 1/2 and anywhere between a 40-45 Caliber BPCR I would determine the desired COAL, first.
Then establish the volume of powder necessary to fill the case to the bottom of the bullet to hold the bullet at that COAL. Next.
I would weigh that volume of powder, (write that weight down), subtract one grain from that weight and add a .025 card & .030 poly.
Waxed card against the base of the bullet. That is your starting load. Change nothing but the weight of powder in increasing 0.5 grain increments.

Yeah, I know all about the whizz kids wanting to know about the wads, well, when you start upping the compression they will come in handy. AND, sometimes, not always, I have to fall back a bit and substitute a .060 poly for the .030 poly in the big boys.

I have to do this in 10 shot increments because I plot shots on paper using a spotting scope at 200 yards. You are not so restricted.

So far, this has worked on every BPCR I have used. No exceptions. BTW, this is 40-45 caliber. This is for Swiss 1 1/2.

You have a problem when all ten shots print, more or less are touching, well within a 3" circle. It happens. Not saying it will happen for you.

[TexasMac]

I agree with martinibelgian. A ladder test with increments of 0.5grs is sufficient to identify the velocity sweet spot.

Firing several rounds at one target then repeating the process on additional targets with incremental powder charges is not a ladder test, it's referred to as Optimum charge weight (OCW) testing.

When using the ladder test or OCW test it’s common to identify a couple of potential sweet spots given sufficient number of loads. They’re usually separated by several grains of powder. Assuming two sweet spots are identified I use Brent Danielson's “The 2-shot Way” to determine the better of the two.

I hope everyone had a great Christmas.
Wayne

[ian45662]

When making a test with .5 grain adjustments how many shots will you usually make in a season ? And DD …. Deans does think I’m special but maybe not in a good way.

[desert deuce]

Yeah, well....I will leave that "SPECIAL" determination/classification up to you two.

A little heads up though, and I presume you probably already have or soon will find out, the OCW or ladder test is basically a starting point. As Texas Mack alluded you may encounter more than one sweet spot as you travel up in charge weights WHICH SUGGESTS don't stop at the first sweet spot.

This, for you, may prove important because you shoot silhouette to 500M and target out to 1,000 yards. A harmonic velocity at the lower charge weight may be sufficient in velocity for excellent vertical to 500M yet may not have enough horsepower to maintain vertical out to 1,000. Here is where I have found the chronograph useful. True it is that the general consensus is a 500-540 grain .45 cal bullet travelling 1300-1330 fps is optimal for long range. Well, yes and no. What is optimal is what the combination of shooter, load and rifle perform best at 1,000 yards and single digit ES is a strong predictor of which load in a particular rifle wielded by a particular shooter scores highest. Maybe coincidence, BUT, usually that single digit ES seems to fall frequently into that velocity range.

Now, in a sincere effort to inform further, the concept of a BALANCED LOAD applies to the application or the intended purpose. You don't need a 540 grain bullet travelling 1300 fps in a 11.5 pound rifle to knock over a Ram regardless of how much you may enjoy recoil therapy. Loading that same rifle and bullet to 1120 fps for best silhouette and midrange performance probably will fall short of optimum performance at 1000. And, the fly in the ointment here is the prevailing conditions when the trigger is pulled and it takes a lot of trigger pulling in different conditions to figure that out.

For instance. You are second shooter on your relay. You are spotting for your partner first relay and he posts a 96x4 on the 1000 yard target and you only give him 3 minor sight corrections for his ten record shots. Now it is your turn on the mat. As cease fire is called for relay one a 9 O'clock wind picks up, the flags start pointing upward and it starts with blowing dust and transitions into blowing fine gravel as the 3 minute prep period is called. FIRE is called. You put a rock on your patch container to keep it from blowing away. Based on a SWAG you put on 32 minutes left and hold on the left side of your target for your first sighter and hit the center of the pocket of the target frame to your right. You know you have 44 minutes windage on your rear sight but that is not enough to hold on your target and hit it. Ten sighters later and running low on time you adjust windage to 30 minutes left windage and hold on the target to your left you cut paper, a 7 at 2 o'clock. Going for score and shooting fast you end up with a 46 and the uninformed look at the match results and wonder why you scored so low? But, they don't know that was high score on that relay, or, that was the last relay that day. However, the informed have a pretty good idea what happened because they have been there and done that. And, on that relay that day the wind was your friend.

[Kurt]

I think we all do a different way to develop a good load for the rifle we use and the distance the test target is setup. I'm limited to 200 yards so I do the best I can with the loads I take to the match.
I tried Brents 2 shot ladder load test and it works. But I like to use three or a five shot test so I have a better average and to eliminate the possibility for a bad break and I look at the closest shots in that load.
I start at zero compression with three shots and increase the next three by a 1/2 or a grain for the next three but usually I don't see any difference between the 1/2 grain loads and the one grain load but this could be my error with a bad break that is why I like three or 5 shots. And still I only shoot 12 or 25 shots before the compression gets at the max.
Below is a typical test shot targets I shot with my .38-50 Hepburn when I got it using different types of powder and primers.
The orange pasters are 2" I can see with a scope.

IMG_0765.jpeg

This target I try a different primer with the load that was the best for the first test to see how different primers affect the load I used on this target 2.5 Rem LP, Fed 210 GM LR and of all things CCI LR Mag Primers.

IMG_1401 2 3.jpeg

And the final test will be at least 10 or more shots to see if the load will stay together for a 10 or 15 shot relay.

IMG_1325 2.jpeg

All of the shots fired are not a waste spending time with the rifle learning to use the sights and controlling the rifle.

[ian45662]

I am going to test a couple of bullets and powders in the 38-50. .5 grain made the compression jump pretty fast. I did .3 grain adjustments for this. I will do .5 for the 45. My first sample is 25 shots. Starting with 55 grains and 0 compression up to 62.1 which gives me .240 compression. Baco 360 grain money bullet with 2 reduced bands. Swiss 3F powder. I will do this with 1.5 also. Then test 3F and 1.5 with the same rifle and a 365 grain Creedmoor bullet.

[desert deuce]

Interesting, as I know comparatively nothing about loading the 38-50 Hepburn.

[ian45662]

Interesting, as I know comparatively nothing about loading the 38-50 Hepburn.

I can’t imagine that it would be much different than what you’re already familiar with ….. just a little smaller. Less volume. Kurt I am just going to try the one shot stuff for now and if we find some potential loads I think I will load up some 10 shot loads of what might look best and then try and get back out on Friday and verify. Normally I just make a bunch of 10 shot loads and vary each change by a grain. Might make 5 loads if that for a total of 50 shots. Hopefully this will work out for me and I won’t have to do that.

[Kurt]

Let us know how things work out.
I seldom shoot less than 50 rounds when I'm at the range. D: But I well say this little shooter is not fussy what the load is I feed it.