Does a ladder test verify what the objective muzzle velocity will be?..

[PlinkIt]

As I understand it right now a ladder test will help me time the bullet to muzzle at a node of flex in the harmonic sine wave of the barrel.. Now assuming I have done that with the method in the precision instructions in the sticky set above.. I learned my node point with oal set to max.. Now if I make any changes to the load will my objective be to match that muzzle velocity I learned to be right.. Or when any variable in the cartridge is changed I will have to complete test again?..

 

[TimeWillTell]

I am also interested in the answer to this...

 

[Niles Coyote]

I don’t shoot ladders, OCW is what I usually do or a hybrid of the two, then fine tune at distance. What I can say is once I have found a node, small changes like primer brand or bullet brand (still within the same weight class) don’t have much effect on the node. The best powder charge may not be exactly the same (may need to +/- a tenth or two to get centered again) but I don’t remember ever needing to start over or make a large change... the difference tends to grow with the bullets bearing surface difference in my experience. This assumes jacketed lead core bullets are being used.

 

[PlinkIt]

I don’t shoot ladders, OCW is what I usually do or a hybrid of the two, ...

Thanks, I will try to do some more reading on the OCW test I remember reading something about it but really don't remember the principles and process.. Perhaps it will fit my situation a little better thanks

 

[Welch]

Yes, when changing seating depth, your node will likely change. The amount this changes will depend the distance between the bearing base of the ogive to the lands of the rifling. For example, if your initial load was developed with the bullet seated 0.020" from the lands then you change the seating depth to 0.010" using the same bullet and charge weight, the pressure will increase. This increase in pressure will change the magnitude of the impulse and change the location of the node.

The link below has a section about seating depth and it effect on pressure.

http://m.hornady.com/ballistics-resource/internal


Hope this helps


Sent from my iPhone using Tapatalk

 

[rcamuglia]

Audette's Ladders are my preferred development tool. If you change anything on a load you have derived from an Audette, I would re-shoot the Audette with the changes.

Here's one I shot on Thursday with the Creedmoor at 600 yards. New lot of H4350 from 41.3 to 43.1 in .3 gr increments, 139 Scenar...




Load 5 at 42.5 grains was the middle of the giant node, so I loaded 4 and shot them at another aimpoint at 600...




group measured 2" with the one shot giving the group 1" of vertical. The rest was wind.

As you can see from the ladder itself, it was windy.


Shot 5 at 100 to confirm:

 

[M36]

Audette's Ladders are my preferred development tool...............

Correct me if Im wrong, it looks like you have done a reverse OCW. Shoot for distance but verified at 100 yards. Very interesting, nice shooting!

 

[rcamuglia]

It is not a reverse ocw. It is an Audette Ladder or Incremental Load Development.