10 shot ladder question

[sleeplz]

I conducted a satterlee method load development using 6.5 creedmoor, magnetspeed v3, 140 berger hybrid match, hornady brass, and H4350. My question is, would 42.8 be my sweet spot?

 

[Deleted member 113831]

The Saterlee method is inappropriate for your combination. Scott was using heavy for caliber bullets (147's) and slow for caliber powders (4831 burn rate). He was packing them to 100+% load density at max pressures.

You are at least a grain over pressure. See that spike going from 42.3 to 42.6? That is what's called a clue.

 

[ToddKS]

For that combination I would expect the "sweet spot" to be found somewhere between 41.0 and 42.0 grains.

 

[A&8's]

Going with the charges in the OP, personally I would load 3ea of 42.6, 42.7, 42.8 and 42.9. At 200y, shoot for group size, ES and SD. Once smallest vertical has been established, change seat depth in 5 thou increments to shrink horizontal.

 

[Deleted member 113831]

For that combination I would expect the "sweet spot" to be found somewhere between 41.0 and 42.0 grains.

Yep, based on where pressure showed up, I would guess 41.5 or 41.7 grains.

 

[sleeplz]

I shot 41 through 42 grains of powder but was getting 2600. My brass looks fine at 42-43. For those saying I should stick between 41-42, is it because my sd's will be lower? I'll try graphing those results and seeing what I get.

 

[Deleted member 113831]

I shot 41 through 42 grains of powder but was getting 2600. My brass looks fine at 42-43. For those saying I should stick between 41-42, is it because my sd's will be lower? I'll try graphing those results and seeing what I get.

Your graph shows 2775 at 42.3. Are you saying 0.3 grains showed an increase of 175 fps?

 

[sleeplz]

I'll have to redo it again. But when I was in the 41s it was in the 2600s. I'll try to graph it once I get back in town

 

[ToddKS]

You really need to stop trying to rely on a singular data point to establish velocity. You need to fire multiple rounds. I understand what you are trying to do, I just have not found that approach to be effective personally. I would start by loading 5 rounds each at 41.0, 41.5, and 42.0. Report back with the average velocity and SD for those charge weights. Fire them round robin.

I have used the components you are using in 3 different 6.5 Creedmoor barrels. The information in your chart aligns roughly with what I would expect at those charge weights. 2600 between 41.0 and 42.0 does not. Something is not right.

 

[spife7980]

I would quit trying to figure out how a load shoots without seeing how it shoots. Use the velocity numbers in addition to the target, not in place of.