ladder test results, advice needed

[hogslayer]

I like to tune with positive compensation.  To me it helps with any temp swing you would see in a hunting situation.  This is a ladder I shot last month.  Changes primers and the (3) powder charges ended up being 16 FPS apart when shot again.

[BULLBLASTER]

I stopped doing the “three rounds of each weight” thing when I realized I didn’t care about accuracy nodes at low velocity. Yes I realize that sometimes we want a light recoiling easy shooting load. That said, I believe most of us reload for high performance and consistency. In that case, why shoot all that powder for loads that wouldn’t interest the shooter ballistically regardless of accuracy.

Yes accuracy is the paramount factor in precise shooting. But by playing with powders and primers and seating depth a bit, it’s rare that one can’t find a spicy load that shoots tight groups too.

How do you fine tune around your upper end load then?  I do 3 or 4 shot groups around suspected upper node suggested by ladder test and quickload and watching for velocity plateau but maybe there is an easier way ?

I think the jon was saying that he won’t use up lots of components on lower velocity loads. I do the same. Work up to find max load and then fine tune from there. There isn’t a need to shoot a min starting load for groups imo if it’s 100-200 fps lower than the cartridge is capable of.
Basically the same as you but without quickload.

[Magnum_Willys]

Got It! I agree I just cant bring myself to search lower velocity rounds for a node either tho I know Im needlessly handicapping myself by being speed hungry.

[BULLBLASTER]

Got It! I agree I just cant bring myself to search lower velocity rounds for a node either tho I know Im needlessly handicapping myself by being speed hungry.

That’s because faster is always more better! 

[wooltie]

The upper end shot MOA, once LOL. 

I loaded up 5 charge weights in 3 shot groups and watched the rounds go from no group to group.

Still have to load up more rounds of that charge weight and play with seating depth to verify that load groups consistently, but it's a start.

165g accubond,  56.5 g IMR4350.

I understand and like the theory behind the ladder testing using a chrony to obtain data and ignore target impact.  Find the flat spot, load around the flat spot to verify groups, adjust SD accordingly.  I saw inconsistencies between the point of impact and the measured velocity.  Some higher velocity shots actually impacted the target lower than lower velocity shots.  I ran with the flat spot, but couldn't get the rounds to group at all after adjusting for seating depth.  I might have messed up somewhere, or my rifle just doesn't these bullets in 180g.

Can anyone explain why a higher charge weight might produce a point of impact lower than that of a lower charge weight?  I would expect the ladder to go up, up, up, flat, flat, up, etc...not up, up, flat, down, up, down, up, up.

[jasnt]

Barrel harmonics

https://m.youtube.com/watch?list=PLJUaiRIEduNXoal2_PkBZi0vDCIcEPxUn&v=ilT_U5uHJk0

[Magnum_Willys]

Imagine your barrel as a tuning fork vibrating up and down or oval like a clock face. You want round to leave just before top or 11 oclock. Rounds that are slightly faster will leave when barrel tip is lower to offset their higher impact due to higher speed.  The 12 oclock position is the node.