Help me interpret this data! (Picture Heavy)

[bluedixon]

Hey nutters,

Ive recently started reloading. In fact, this is the first 50 rounds Ive ever loaded. I'm hoping some expert reloaders can help me figure out where to go from here.

Data:

Target:

This is 40.8, and 41.0 brass. Notice the faint ejector marks.

A closeup of 41.0

All targets are shot at 100 yards. Ignore the 39.2, as I needed to zero the rifle with the magnetospeed on it, however I forgot my factory fouling sight in boxes.

You'll also notice that the chronograph didn't catch any 40.2 data. Apparently it works better if its plugged in. Grr.

As you can see, there is some pressure sign when I hit 40.8 grains, but faint.

41 grains produced more noticeable ejector marks. It appears from the targets that 40.6 had the least vertical dispersion, and groups stayed nice as I went all the way to 41. The 40.8 flyer was me. 100 percent.

Is this the wheelhouse I should concentrate my efforts? 39.6 shot awesome, but .2 grains either way and they open up heavily. Not as consistent as I would like.

These are loaded for 0.026" jump, and 0.002" neck tension

Any help would be appreciated!

Blue

 

[Ganderite]

The case head is sold brass. When it starts to extrude into the ejector hole on the bolt face, you are up to proof round pressure.

Unless this is a bench rest rifle, I would not test at 100 yds, because grouping at 100 does not translate at all to down range performance.

The shortest I test at is 300, and I prefer 500. And that does not tell me much about long range performance.

Your ES &SD numbers are very good. If it was me, I would try .003 neck tension and repeat at a useful distance.

And get a black square to aim at. The crosshairs will line up very accurately on the corner.

At short range I use a patch.



For 500 yards I cut black paper into 3" squares and glue them on a big sheet of paper.

 

[bluedixon]

Thanks for the reply, Ganderite. I figured 100 was a poor choice.

I'm using redding competition bushing dies, so neck tension changes are easy. Should I chrono these 0.003" tension rounds also?

I had some POI shift with the chronograph attached, so I hoped to proof my velocities and hone in on a velocity node which is consistent, has little vertical dispersion and has no pressure signs.

Once I have my powder charge chosen, I would then shoot for groups at say 300 or further as you recommend. I could then adjust bullet jump to further tighten groups. Would you say this is an efficient method?

 

[bluedixon]

I forgot to mention that in the interest of science, I loaded up another 50 rounds utilizing the same charge weights, but with 130 grain Berger Hybrids. I stretched the jump to 0.040", with 0.002" neck tension. Would you say 2 thou tension is too little?

I'll be sure to test them as you recommend at longer distances.

 

[220]

I would say your 40.8 load is the good one but take off chronograph and try again, measure that one hole against size of your bullet ie: measure hole subtract bullet dimension.

 

[bluedixon]

40.8 looked promising, but I hesitated loading any more at that due to the light pressure signs. I had considered loading 5-10 rounds of 40.6, 40.7, 40.8 and testing those.

 

[Lead hammer]

40.6 has no verticle, load it and on either side of it. 40.4 impacts the same position, and 40.8 is just slightly higher, so 40.7 May line up with 40.4, 40.5, 40.6, and 40.7. Test those. at 100 still. Then test the middle node at 300. 100 still can work for testing OCW.

 

[Ganderite]

Does the chronograph touch the barrel? I am not familiar with that model.

I suggested 003 of neck because I found more neck tension improved ignition.

 

[bluedixon]

Ah, its interesting you mention ignition. I'm currently uniforming my flash holes.

Yes, the magnetospeed pictured below straps to the barrel.

 

[Lead hammer]

Wow I wish my weather looked like that today. I almost got stuck in the snow driving into the range, the wind was blowing full plastic boxes of ammo over on the shooting bench along with closed gun cases.

 

[yodave]

pick a middle powder weight, seat the bullet with a 40 thou jump and work into a 10 thou jam in 5 thou increments, when you have the least amount of vertical then change your powder weights and work them up in .3 of a grain increments till you get the sweet spot, then fine tune the seating depth again to ring out any vertical. Playing with the VLD bullets without testing seating depth first is a real waste of time, they are more finicky about seating depth then they are with powder load, given the cooler temperature you were shooting in I would back down at least a half a grain and concentrate there because in the warmer days of summer your going to be back up at pressure signs if you don't

 

[bluedixon]

pick a middle powder weight, seat the bullet with a 40 thou jump and work into a 10 thou jam in 5 thou increments, when you have the least amount of vertical then change your powder weights and work them up in .3 of a grain increments till you get the sweet spot, then fine tune the seating depth again to ring out any vertical. Playing with the VLD bullets without testing seating depth first is a real waste of time, they are more finicky about seating depth then they are with powder load, given the cooler temperature you were shooting in I would back down at least a half a grain and concentrate there because in the warmer days of summer your going to be back up at pressure signs if you don't

Great advice, Dave. I hadn't considered this. I also noticed that I couldn't let the rounds sit in the chamber for any amount of time, or it affected the FPS.

Just finished loading these. Interested to see if the 39.6 will maintain its accuracy. Currently these sit at 0.025" jump, but I could seat them deeper if need be.

Wow I wish my weather looked like that today. I almost got stuck in the snow driving into the range, the wind was blowing full plastic boxes of ammo over on the shooting bench along with closed gun cases.

Ugh, gross! If it makes you feel any better, I was falling some timber in Moses Inlet and this was our weather last week.

 

[yodave]

I'd take the 39.6 and play with different seating depths, if you can get the desired accuracy with a mid range load just think of how long that barrel will last

 

[bluedixon]

Appreciate that, Dave. Especially considering that from 39.6, to the first pressure signs at 40.8 there was only a difference of 80ish FPS. I had read that seating depth is where it counts, but have yet to test any appreciable differences.

 

[ydg]

Wow I wish my weather looked like that today. I almost got stuck in the snow driving into the range, the wind was blowing full plastic boxes of ammo over on the shooting bench along with closed gun cases.

You sir did not choose a great day to go shooting >_<

 

[Lead hammer]

Lol I have 2 young boys, gotta do what you can, when you can.

 

[Ganderite]

Accuracy is a function of barrel quality, bedding, action screw torque, bullet quality, powder charge, seating depth and BARREL HARMONICS with all the forgoing.

You can check velocity, but not when shooting groups. That chrony strapped to the barrel ruins everything.

All that test did was confirm that 2 loads were too hot (around 70,000 psi, my guess) and give you velocity, SD and ES readings.

Repeat the test, leaving out the top 2 loads. Shoot for accuracy at a better aiming mark at longer ranges and see how the rifle shoots.

 

[nevanevan]

I would.go 39.6 as all the sd numbers between 39.4 and 40.0 are all less than 7 which is excellent

 

[bluedixon]

Apologize about the delay. Spent all morning in this ugly thing.

I probably should have held off on shooting today. It was brutally windy. 75 shots took me 3 hours waiting for the wind to die down enough to shoot. Not to mention the .338 Lapua 3 tables over giving me brown stains in my underwear.

I took your advice, Ganderite and set up as far as the range would allow. A measly 250 yards. No chronograph either.

As you can see, 39.8's 5th shot is the X a foot below due to a major flinch on my part from that muzzle brake 3 tables over. 40.7 looks good, but again into some light pressure signs.

I still feel as though my sweet spot is going to be around that 39.6 weight. I should try a few loadings around it with alternating seating depths as suggested.

I figured while I was out, Id blow off some 130 Berger Hybrids at 100 to see what they would do. Not surprising that they want to get pushed a little harder.

Ignore the 39.2. I had some zero stop shim issues. Appears 40.0-40.2 is promising with these 130's. I didn't hit any pressure signs until 41.0.

Next time, I'll do as you suggested Ganderite. The red circles work great for me at 100, but at 250, the center of the crosshairs make them all but disappear.

 

[Ganderite]

You are looking for consistent, repeatable accuracy. Is the action bedded into the stock?

Do you know the torque on the front and rear action screws?

If it is not pillar bedded, I suggest 35 in front and 25 on the rear. If pillared, 65 for both.

In a calm day, pick the promising load range, aim at a black square (at the corner), and fire 10 shots of each. Shoot slowly, so as to not get the barrel too hot. My experience is that a 5 shot group can be very deceiving. I have fired lots of 10 shot groups in which the first 5 were nothing like the end result.

If you put the 10 rounds in your shirt pocket, the ammo will be summer temp when you test it. Otherwise you are developing cold weather loads. Different in the summer.

I take the ammo to the range in a picnic cooler with a 2 litre Coke bottle full of hot tap water. keeps in nice and warm until it goes in to my short pocket.