Ladder Test for finding powder charge

[Forkyfinder]

Unless you're doing 10-round+ samples size at each charge, you're kidding yourself...

Obligatory post:

Yup. You dont really have enough data to have any statistics that you should have any confidence in.

The people who are talking about their ES/Std dev with 5 shots make me laugh .

 

[Wind Gypsy]

You sure don’t need 10 rounds to find out what’s NOT good. JFC. Ladder test is to get a starting point without shooting a ton of ammo, right?

If you shoot a 2 shot “group” that sucks - why waste 8 more?

I don’t disagree. It’s just seems that seldom does a little tweak in charge weight take something from lousy to good repeatably unless it’s on the extremes of high or low pressure.

 

[Wind Gypsy]

Unless you're doing 10-round+ samples size at each charge, you're kidding yourself...

Obligatory post:

The follow up to this about how they’d do load dev is a good one. Not really what i do but close enough.

 

[Frequently Banned Troll]

I don’t necessarily disagree. It’s just seems that seldom does a little tweak in charge weight take something from lousy to good repeatably unless it’s on the extremes of high or low pressure.

So what’s the best route? New bullet, powder, primer, etc. Fastest way to get to a good place to hone in, with fewest of amount of fired rounds? In the past, I’d pick a 3-4gr spread and load up a pile of 3-5 round groups to hone in, this way seems like I can get to a better place, quicker.

 

[Frequently Banned Troll]

Like I said - my fist try at this and hope it’s useful for intended purpose. For me accuracy is more important than velocity.

 

[It’s Bucky]

Like I said - my fist try at this and hope it’s useful for intended purpose. For me accuracy is more important than velocity.

Curious GH, what’s your accuracy goal? How many rounds do you shoot to establish your cone of fire and zero?

 

[mtmuley]

Like I said - my fist try at this and hope it’s useful for intended purpose. For me accuracy is more important than velocity.

After today I bet you will have a better idea if it works for you than just advice from others. mtmuley

 

[Frequently Banned Troll]

Curious GH, what’s your accuracy goal? How many rounds do you shoot to establish your cone of fire and zero?

I’m pretty happy with a “true” 1” or less rifle at 100m. A couple 5 shot groups all inside that are good enough evidence for me with some proof at long range.

 

[slatebuilder]

I'll ask a dumb question, what else are you guys doing if not ladders?

Everyone has a process that works for them, and that’s cool. Here’s mine for bullets with adequate known data. I’ll preface this by saying that making sure action screws are torqued, bases and rings have the correct screws and are torqued correctly on the rifle is important. I have had several rifles now that were not done correctly by either the factory or people that should know better.

I load one at book max for the given powder and bullet.

Seat it to mag length or put the boat tail junction at the neck should junction.

Shoot into the bank behind the garage. If it shows any sign of pressure at all, back off either 1/2 or 1 grain, depending on case size. If it does not show pressure I load 10 more and go to the range and shoot it at 100.

If it meets my needs, then I load the rest and go shoot. Most of the time that gives a load that is usable for our hunting and shooting purposes in 11 shots.

If it does not meet my needs, I change powder and repeat. If a rifle and bullet will not shoot adequately on two different powders I try a different bullet. If it will not shoot on two bullets and four powders, there is something wrong with the firearm.

If there is little or no data available for a given bullet, then a pressure ladder is absolutely necessary. And once I find pressure, I follow the steps above.

 

[Carl]

So what’s the best route? New bullet, powder, primer, etc. Fastest way to get to a good place to hone in, with fewest of amount of fired rounds? In the past, I’d pick a 3-4gr spread and load up a pile of 3-5 round groups to hone in, this way seems like I can get to a better place, quicker.

I won't claim to have "the" way, but I'll tell you what I do.

With something I'm very familiar with, like 6 Dasher, I just pick a load based on experience. I might only load 20 to confirm, or depending on circumstances I might load a couple hundred. I've competed with three loads out of my current match barrel and this is what I did for all of them, and the few barrels before that haven't looked much different.


If I'm working with something I'm less familiar with, there's a little too much uncertainty with that approach. I pick the bullet and powder I want to use, find where the bullet sits ~ .030" off lands (assuming it fits in the magazine there), and take a press and powder thrower to the range. I'll load and shoot single rounds over the chronograph, watching velocity and looking for pressure signs. Once I find where I want to be (usually not close to pressure), I'll start loading rounds and shooting a group. Will probably shoot a 10 shot group, but if the first few show it's unacceptable there's no need to continue.

If that doesn't shoot, I might tweak seating depth deeper and try again. Then try a new powder. Then try a different bullet or two. If I still don't have acceptable accuracy, new barrel time.

There's plenty of details and nuance, but that's the general idea. Good luck with your shooting.

 

[schmalts]

Ever done that? Was it a good use of time?

I’m trying it for the first time this weekend. Two rifles, same caliber (6.5prx) 2 separate loads - every component is different. I’m hoping I can hone in on a good recipe in 2 times out shooting. Will see.

I’m going to shoot at 300m because parallax is that for the optics but will plot both impact and velocity.

Yes. time consuming. but it worked out. It's not all about the group size when looking at your 5 round samples. You also want to look at the change in elevation. Key in on a powder charge that has a pause in elevation change as well. The idea is about having the bullet exit the barrel in the turn around time where it dwells before it changes to go the other direction. This gives you more room for error when it comes to temp changes.

 

[slatebuilder]

Like I said - my fist try at this and hope it’s useful for intended purpose. For me accuracy is more important than velocity.

Looking forward to hearing what you learn. This thread might be a good place for some of us to learn some new things.

 

[WapitiBob]

Like I said - my fist try at this and hope it’s useful for intended purpose. For me accuracy is more important than velocity.

The one thing that affected accuracy the most for me was to put the bullet boat tail jct at the top of the case neck/shoulder radius; night and day difference in two different 7's. No idea what bullet you're loading but the prc is made to seat the bullet long.