100 yrd Lader Test. So much for that?

[Rick Ratzlaff]

So much for that 100 yrd Ladder test! New to me 243 Savage 110 Apex Predator. Vortex 5-25 PST Gen 2. 62 gr Barns V Grenade.
H4350 41 to 45.5 in .3 gr incraments. Varget 37 to 41.2 in .3 incraments.

I guess I gotta do it all over again and stretch to 300 yrds.


Guess I didn't learn much from that?

 

[RegionRat]

I have the opinion that there isn't much point to the shot pattern of a 100 yard ladder test for a modern centrfire design, especially one that is expected to shoot <0.5 MOA later on.

Since most centerfire cartridge designs will not "spread" very much at 100 yards due to the sweep of either the charge or the depth, you should consider the rough distance that will help with making the shotfall readable. Even 300 yards is pretty close but much better than 100 where many shots stack.

I realize lots of folks will jump into the discussion who will say 100 yards is enough cause they don't look at the holes and only measure velocity, but I would come back and say why not get both at the same time?

Unless of course access to a longer distance is an issue, then by all means you do what you can.

If you are able, I would shoot those tests at the maximum shooting distance you plan to compete with, or hunt within. You need not worry about wind calls by tracking just the vertical components during the powder charge sweep, but it helps to test on relatively calm days in general. On the other hand, OCW testing and group testing can be done at 100 without being as hard to read. Those tests use an aimpoint per test point and you can run many test points on one target.

 

[Rick Ratzlaff]

Thanks - I've experienced much wider spreads at 100, and read pretty experienced shooter say 100 is enough so I expected more info. Maybe this is the most accurate rifle I've owned??? A third powder definitely showed more spread so I'll reject it. My sun dependent chrono failed. So I guess this is just a learning TAX.

 

[Frans]

You should have also measured speed for every shot if you want conclusive results from a 100yds ladder, most of the time you will notice a flat line in velocity (constant velocity) even if powder charge is changed and that's normally in the ballpark for a good load,this touches on the OCW method. But yes you are correct if one wants to shoot a ladder and draw conclusions from impacts/consecutive shots it has to be at distance of 300+ to "see" better what's going on, on paper.

RR is spot on with his advice, shoot at max possible distance and measure velocity (not with magneto speed for obvious reasons or if it is modded to not touch the barrel then go for it)

#Edit# Saw now you mention that your Chrony failed, that's a bummer. Get it fixed and hit the range. Looking forward to results! Group seems promising like you mentioned.

Regards
Frans

 

[Straightshooter1]

Ladder test didn't work well at 100 yds for me either, until . . . I improved my reloading to where my MV SD's and ES's were low. Now that my SD's are single digits and ES are in the teens, a 100 yd ladder test tells me just about all I need to know. Though I'll then shoot further out, like just 200 yds since that's what most available to me, for finer tuning.

 

[G Liles]

I may be wrong but you need to shoot each load at a different target.

 

[ryewhiskeybent]

I may be wrong but you need to shoot each load at a different target.

That’s what I thought too. How else will you know unless you have a shot marker or some way to know which shot was which.

 

[G Liles]

This is what my ladder test looks like

 

[3Sigma]

Yup, BTDT. Here's a 5 step 3 shot ladder with 1 grain total spread. Couldn't go further than 100 yds due to crops and muddy fields.

I didn't have a chrono yet either.

Now, if I use 100 yds, I have separate POA and use the chrono.

 

[Terry]

So much for that 100 yrd Ladder test! New to me 243 Savage 110 Apex Predator. Vortex 5-25 PST Gen 2. 62 gr Barns V Grenade.
H4350 41 to 45.5 in .3 gr incraments. Varget 37 to 41.2 in .3 incraments.

I guess I gotta do it all over again and stretch to 300 yrds.

View attachment 1223400 View attachment 1223401
Guess I didn't learn much from that?

Use different points of aim for each load. Then you can see what is going on.

 

[Terry]

Example

 

[RegionRat]

It is important not to confuse OCW testing with Ladder testing as described by Creighton Audette et al.

His Ladder was intended to find the nodes by study of the vertical shotfalls. So for a Ladder test a single aimpoint at a distant target creates a non-linear result in both velocity and vertical, for a regular increment of charge. Later on, folks added seating depth to that same method as a natural extension.

Not that some rigs won't have a spread of over an MOA for the charges, the point s many will not and that is the better problem to have. The method suffers from the issues of "small sample size" so we must keep in mind that there is an "uncertainty cloud" around each shot. The general idea is to go out far enough on the speed curve that the drops between shots are at least as large or larger than those uncertainties. It helps to give the method leverage for where it lacks in samples.

The OCW test has traditionally watched for the center of low sample groups and lends itself to shorter ranges. Could be we are smearing the two concepts together now and then. I don't know.

I have tested +100 year old Swedish Mausers where a whole three grain sweep only went from the bottom of the 10 ring to the top of the 10 ring, and I have also tested sporting rifles that nearly went from the bottom to the top of the 600 yard frames. Testing efficiently takes some experience and also some luck. At first, it is hard to know how far out the Ladder test should run in order to make the nodes obvious compared to the uncertainty of any given shot.

Using a ballistic calculator with an estimated speed from a loading manual is a good starting point. If the estimates are showing drops in steps that are smaller than the expected accuracy of the rig, then push the distance out till it makes reading the spread easy.

Anyway, good luck and Happy New Year.

 

[Rick Ratzlaff]

Thanks ya'll. The sun dependant Chrono failed me as well. Double wammy. Gonna borrow a different one next time. My typical policy is to extend the distance to as far as I can go and yet see movement between scope and target. So it depends on the scope's power. I do have sheets printed 4ft wide and graphed in mm squares. So I could use a different aim mark with each shot. I'll give that some thot.

Blessed 2021. We all now have "2020 hindsight"

 

[Doom]

100yds, no chronograph, Newberry’s OCW method.

 

[JohnKielly]

Also, that is a very coarse aiming mark for 100 yards.

This is my 100 yard test target.

 

[Rick Ratzlaff]

Ya all around we weren't very committed. we were freezing our butts off. My cases are re-loaded. Maybe tomorrow.