Is this a good ladder test?

[Kevin S]

Hey there folks! Like many, I'm relatively new to the reloading thing. Been reading a ton, slowly acquiring components, etc.

Anyway; I'm finally at the point where I'm going to put all the pieces together. Want to run a ladder test for some 270 WSM loads.

I'm looking at a starting load of 52.8 gr (RL-17 pushing 150 gr Nosler accubond spitzer bt), and a 'never exceed' load of 60.0 gr. (according to Lee 2nd edition).

Would a decent ladder test include five increments at (1.5 gr steps);
52.8
54.3
55.8
57.3
58.8

Trying to find a good node to work around, figure that gives me a decent spread.

Thoughts?

[mark501w]

Try a gr at a time. I've got a gun that from 46-47gr things happen fast. Alternating between ok primers & primers that are smashed. So with this gun 1gr increments are too much approaching max. Remember your loading a Hot Rod cartridge same cases ,same powder ,same bullets,same primers, if you change anything reduce your max by 5% & work back up.

[ExtremeX]

I only load for .223 and .308 right now... but most of my ladders follow 0.5gr increments for rifle loads for my initial test ladder... and I drop it down to 0.2 to 0.3gr as I get near max...

I don't know if 1.5gr is too coarse for that caliber, but common sense would suggest that as you get closer to max, you should be using smaller increments.

After your initial ladder, if you find a charge that looks to get better results, go back to that charge and do another ladder in finer increments above and below that charge to find an accuracy node.

[mark501w]

When I say change anything, I mean if you go buy another pound of powder another box of primers ect reduce your load.

[Kevin S]

Thanks guys; this is incredibly helpful! I'll shrink my increments and go slow.

Great advice on the 5% reduction with new lots of powder/primer. This cartridge eats through powder quick .

[five.five-six]

Thanks guys; this is incredibly helpful! I'll shrink my increments and go slow.

Great advice on the 5% reduction with new lots of powder/primer. This cartridge eats through powder quick .

buy bigger jugs of powder and lots of primers.

[CobraRed]

I either do 1/3 or 1/2gr increments. It REALLY helps finding the perfect recipe.

[BLR81]

Hey there folks! Like many, I'm relatively new to the reloading thing. Been reading a ton, slowly acquiring components, etc.

Anyway; I'm finally at the point where I'm going to put all the pieces together. Want to run a ladder test for some 270 WSM loads.

I'm looking at a starting load of 52.8 gr (RL-17 pushing 150 gr Nosler accubond spitzer bt), and a 'never exceed' load of 60.0 gr. (according to Lee 2nd edition).

Would a decent ladder test include five increments at (1.5 gr steps);
52.8
54.3
55.8
57.3
58.8

Trying to find a good node to work around, figure that gives me a decent spread.

Thoughts?

When running a ladder test your looking for consecutive powder charges that group close together. That way you don't have to weight every load when your loading. If your off by a tenth or even two tenths of a grain your still going to group your shots close to your POA.

If you start in 1.5 gr increments, your sample size is too small, and more than likely most will evenly spaced. Eventually, your going to want to finish your testing in at least 0.2gr increments, so you need to start with at least 0.5 or less. The lower you start the less refining you'll eventually have to do.

Where you go from there depends on what your loading for. When I load for my long range target rifle, I'm looking for the group that's closest to the max load. If I'm loading for my hunting carbine, then I'll look for something a little less powerful.

I load in 0.3gr increments from just around 85-90% of max. So starting at 52.8gr is fine. Now, the problem with shooting in 0.3gr increments, is that you will be shooting 24 different loads. And, identifying which hole belongs to which bullet can be difficult especially if your test below 300 yds. Even at 300 yds, those 24 rounds will be spread over about 6" of vertical spread. And, the majority will cluster in about half that distance. Running down the range to mark each shot isn't practical even if your the only one around unless you use an ATV.

I buy some large poster board sheets and a package of multi colored sharpies. Hang the poster board with a small 3 inch target in the top middle. I color the bullets with the markers (usually red, green, blue, black, red/green, red/black). Now adjust the scope about 1.5-2.0 moa down, and shot your colored groups with the windage adjusted zeroed, 2moa left and 2moa right.

The poster board is thick enough that you can push the holes from the back and easily see which color bullet made the hole. You only care about vertical spread so look for a group of 3 consecutive load weights that group the closest together. I like to fine one that fits the purpose it's meant for and another in the low to mid range to be used as my practice load.

Take the nodes that group the closes and reload those in 0.1gr increments and shot 5 rounds of each at separate targets to find the most accurate. Hope that helps. Remember that a ladder test's accuracy is reliable only if your marksmanship skills are reliable. If you have trigger control or flinching problems, your going to put more vertical spread in the test than your ammo. So make sure you can group your shots well before you start.

[GeoffLinder]

Another good thing is to fire over a chronograph and chart the velocity of each charge weight. When you find a node, the velocity is the key. That way you know the velocity for a node and later if you change anything like OAL for jump tests, you can make sure you return to that velocity.

Remember that the nodes are based on a specific velocity so you should identify nodes by velocity in addition to charge value. Anything that effects velocity will change node, so charting charge weight alone is not enuff IMHO.

If you can do so, using a portable powder measure and press allows you to charge primed cases and seat bullets right at the range and makes the process easier than loading at home and having to go back later to run finer tests.

I like to use large targets with 5-10 aiming points and work with separate aiming points per charge weight. I number each aim point with a marker so I can keep track of things easy. This allows you to shoot 5-10 tests before going downrange to check target face.

More good info on ladder testing here: http://www.frfrogspad.com/loaddev.htm

[Bill Steele]

Another good thing is to fire over a chronograph and chart the velocity of each charge weight. When you find a node, the velocity is the key. That way you know the velocity for a node and later if you change anything like OAL for jump tests, you can make sure you return to that velocity.

Remember that the nodes are based on a specific velocity so you should identify nodes by velocity in addition to charge value. Anything that effects velocity will change node, so charting charge weight alone is not enuff IMHO.

If you can do so, using a portable powder measure and press allows you to charge primed cases and seat bullets right at the range and makes the process easier than loading at home and having to go back later to run finer tests.

I like to use large targets with 5-10 aiming points and work with separate aiming points per charge weight. I number each aim point with a marker so I can keep track of things easy. This allows you to shoot 5-10 tests before going downrange to check target face.

More good info on ladder testing here: http://www.frfrogspad.com/loaddev.htm

Great advice right there.

I use .5gr increments first pass. When bolt lift gets sticky or primers start flattening you are getting close (to max) pressure wise. After I find a couple of promising nodes, the second pass is .2gr increments around the nodes.

[Kevin S]

Hey there folks! OP checking back in after my first ladder test. Ended up doing .5 gr increments and found a couple of promising nodes to play with next time.

Thanks so much for the advice. Given how narrow the nodes were, my original idea would have completely missed them

On a final note; I have to say it was a great experience all around from prepping brass, setting the dies, loading - and ultimately shooting the loads I developed. Aside from the practical notions (cost, quality control, accuracy), the reloading experience has added a certain additional emotional attachment to my shooting.

Thanks everyone for their help, support, and all the great info CG provides in allowing me to expand into this great hobby!

[koehn,jim]

I use half grain increments than once close, use a tenth of a grain ladder. I also photo copy targets so I can put 6 on the back board at the range. I shoot in 10 shot grps so there are fewer false readings. Some times you may get a load that seems to group fine for 3 shots and the rest are all over the place, 10 shots will give a true idea. Just my thoughts.

[Whiterabbit]

I actually prefer the OCW method, rather than tuning to velocity. Reason being I want discrepancies in thrown charges to result in relatively little change in the vertical dispersion downrange.

Then, when that load is found, I shoot for groups by shrinking the OAL till the groups tighten up.

So far, so good.

-------

Then I have a load that is not sensitive to charge weight in case the powder drop introduces variance (otherwise I have to trickle every case). I can load a bunch and start measuring the speed to check for reasonable consistency (I don't chase tight uniformity) and get a sense of the data input that goes into the trajectory calculators for shooting long range.

[LynnJr]

To the original poster.
When your working up a load using a ladder test use the 1% rule on your powder charges.
If your round is a 6BR which typically uses 30 grains of powder your incremental change would be 0.3 grains
On a 30-06 which typically uses mid 50 grain loads your incremental change would be 0.5 grains.
300 Weatherby would be 0.7 grains and 50 bmg would be 2.5 grains depending on powder used and bullet weight these may need to be adjusted up or down.

Also on a ladder test you are not looking for best groups you are looking for the least amount of vertical dispersion between subsequent shots.If you have 3-4 shots in a 2 inch wide group with 1/8 inch of vertical that would be a better load than a 1 inch high by 1 inch wide grouping.

You will fix the groups with your seating depth.

[GeoffLinder]

To the original poster.
When your working up a load using a ladder test use the 1% rule on your powder charges.
If your round is a 6BR which typically uses 30 grains of powder your incremental change would be 0.3 grains
On a 30-06 which typically uses mid 50 grain loads your incremental change would be 0.5 grains.
300 Weatherby would be 0.7 grains and 50 bmg would be 2.5 grains depending on powder used and bullet weight these may need to be adjusted up or down.

Also on a ladder test you are not looking for best groups you are looking for the least amount of vertical dispersion between subsequent shots.If you have 3-4 shots in a 2 inch wide group with 1/8 inch of vertical that would be a better load than a 1 inch high by 1 inch wide grouping.

You will fix the groups with your seating depth.

Barrel nodes are not just vertical stringing. When a barrel vibrates, it does not always vibrate up and down. Barrel nodes are entirely velocity controlled.

A barrel can be moving in a figure eight, a small oval, or in a straight line back and forth and this motion can be in any direction depending on that barrel and it's harmonic characteristics. Timing the bullet to exit at the point of least motion is what this is all about.

OAL tuning is done AFTER you eliminate barrel harmonics by finding a node where barrel motion is minimized. Then you keep the velocity at the node and vary OAL to tighten groups even more. This involves changing powder charge after an OAL change to restore velocity to the node point.

Just changing OAL alone will actually take you out of the node because you are changing case volume which changes pressure which changes velocity.