Input on reading a ladder test/final load

[roklock]

Hello,

Did a ladder test yesterday, three different times with very confusing results. Thinking I may have to redo but wanted some opinions. Some background, rifle is a custom Fclass open rig. It has a fresh barrel and before I started yesterday 124 rounds have been shot. It is a 284 win, 32" straight 1.25", bullets are Berger 180 hybrid targets. All rounds are +0.010 into the lands.

I did have a tail wind (7-9 mph) become pretty consistent around shot 5/6 in the 2nd ladder. Distance is 300 yards (max for my range). I don't think I can trust shot 2 on the third ladder, maybe I am wrong, due to a tougher bolt close than the rest. It also produced a spike in velocity

Also, string two showed a couple of pressure signs at the last few shots but none of the other strings did.

Looking for input on a redo or if someone see's something worth focusing on.

Couldn't figure out how to embed without photobucket's add pasted right in the center of it so I have attached them below.

Thanks for any help.

Steve

 

[Mulligan]

Does the third (on right)ladder only have 6 shots?
CW

 

[roklock]

Does the third (on right)ladder only have 6 shots?
CW

good call, yes on paper. I got a chrono result for shot 6 but can’t find it on the paper anywhere. There is a possibility but I don’t feel comfortable calling it.

 

[Mulligan]

good call, yes on paper. I got a chrono result for shot 6 but can’t find it on the paper anywhere. There is a possibility but I don’t feel comfortable calling it.

it looks like 6 and 3 are friends.
CW

 

[Mulligan]

Jim is right, I would look at charges between 3 and 4.
CW

 

[MattPeetz]

Get them .010 off the lands and redo test

 

[gman47564]

Mine likes a mv of 2830.. 28 inch pipe with re23.. might try backing off just a little with the 4350..

 

[roklock]

I like 3
It’s not a large window though

yeah, that’s what concerns me

 

[rsmithsr50]

well I would pass.
i would reshoot with at least 10 maybe 15 rounds in .2 steps
shoot when there is no head or tail wind.
they cause elevation changes, and you are looking for elevation changes in the loads. tuff to do with the wind pushing then up or down.

 

[roklock]

If ya got a decent scale you’re ok,
Try a little seating depth testing at # 3 , window may get more forgiving as the barrel gets more rounds through it.
Maybe a couple of the experts will chime in.
J

I’m using a fx120, v3 for powder. I will try that and I think I will redo the entire test with seating .010 off the lands

 

[roklock]

Another question, minimum temp for doing testing? Been very lucky last 3 weeks with temps mid 40’s to high 50’s.

long range forecast isn’t looking so favorable right now.

 

[roklock]

I would suggest sampling several depth’s in small increments

What I meant to say was I am going to redo the entire ladder test again, just .010" off the lands. Per the suggestion from Matt above. I am also going to load up a seating depth test for the #3 load, per your suggestion. Just trying to make the most out of my range time.

 

[Ringostar]

3,4 and 6. What powder and amounts? I would take the charge from 3 and run a seating test from .010-.035 off. My current barrel likes .027 off. Once you have a preferred seating depth, then I would retest powders.

 

[David Christian]

@roklock, in my opinion you seem to be chasing a high node, which might not be the holly grail of accuracy. Most, and I mean most .284 shooters that I know to include myself will find the middle node closer to 2,790 to 2,820 speed, using the same components as you.

If nodes are 3% apart in charge weight and we assume somewhere around 50 grains might settle out at the right speed for the middle node, the high node would be around 51.5 and the low node would be around 48.5. Any thoughts on dialing the speed back a bit?

See if you can tighten up those extreme spreads.

Consider the middle node with less powder. Jump don’t jam your hybrid bullets...

 

[Ringostar]

I should explain what I did. I tested at .010, .015, .020, .025, .030 and .035 off. 25 and 30 were better than the others. I then retested at .024, .027 and .030 with .027 coming out on top. Then went back and retested powder charge at the preferred depth.

 

[Coyotefurharvester]

If head and tail wind will produce vertical poi shift, does that mean if you have wind(say less than 3 mph) at 6 or 12 and there is very little(a bullet diameter or less) vertical the load is sweet? I only hunt and pd shoot so I tune for minimal vertical at 100 and 200 yards.

 

[rsmithsr50]

within the generalities
yes.

If head and tail wind will produce vertical poi shift, does that mean if you have wind(say less than 3 mph) at 6 or 12 and there is very little(a bullet diameter or less) vertical the load is sweet? I only hunt and pd shoot so I tune for minimal vertical at 100 and 200 yards.

 

[David Christian]

If head and tail wind will produce vertical poi shift, does that mean if you have wind(say less than 3 mph) at 6 or 12 and there is very little(a bullet diameter or less) vertical the load is sweet? I only hunt and pd shoot so I tune for minimal vertical at 100 and 200 yards.

Run a few numbers through a ballistics app and see how small of a distance in drop a 6 or 12 oclock wind moves your bullet with a 10mph wind. Using all the same components as listed in the OP, and a speed of 2,820, my app shows the delta in drop between a 6 and 12 wind of .4 inches at 600 yards. Meaning you should not be thinking about changing your load due to wind conditions.

 

[Hermantk]

My experience suggests that
-you might want to try a few lighter loads as 2830+/_ seems to be where most folks have success with the 180s. It's always seductive to look for a higher MV that yields a node but in my experience, consistency rules and the node at around 2830 is stable. The next node is over 2900 and may present other issues associated with hot loads as well as less consistency.
-with h4350 you should be just fine at the temps you are running but come springtime as they rise to 70+, even though it is very temperature stable, you will want to verify. AND keep notes for future use.
-after you see what looks like a node you may wish to play with larger groups of 6 to 10 to confirm. The smaller steps like 0.2gr increments will show you the center of the MV range that gives you the node. I have even done 0.1gr
-I do my ladders at 300 meters and on days with 7-10mph tail or headwinds, I find that the nodes are still easily identified. On the odd occasion when i get to the range and things are very windy I might do my ladders at 200M and then validate at a later date at 300M.

 

[Hermantk]

in looking at the MVs, it seems to me that you might also want to look at your reloading practices as well. Your ESs are pretty wide for such small groups. Hard to get consistent elevation when your velocities are varying by 20 to 40 fps. You may actually have walked by a node at 50.5gr or 50.8gr