Load Development

[choprzrul]

Where should load development start?

1. Powder type/powder weight/bullet choices done in ladders?

2. Pick a powder/charge weight/bullet combo and then do ladders with seating depth changes?

2.1 For a hunting platform, is 0.010" off the rifling a sufficient safety margin to prevent potential stuck bullets in the rifling?

2.2 If doing ladders with seating depth, do you use increments of 0.005" or 0.010"?

Which comes first....the chicken or the egg type thing??

I've always chased group sizes via powder, bullet, and charge weight testing and used the OAL length listed in load data manuals. Recently I have read where I should find a rifle's sweet spot for the jump to rifling and then pursue powder/bullet combos.

What says the CGN reloading community?

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[mjmagee67]

Load development sucks. I've gotten to the point where I pick an upper middle load. Load 10, shoot them over my chrono if the velocity is fine and they group fine......screw that's what I use. 10 out 10 times upper middle loads give me velocities under max with no pressure signs. 9 out 10 time they group .5 to .75 inch with 5 to 10 shot groups at 100 yards. I'm lazy...

[Rg422]

I’m fairly new to reloading, but had great success following Berger’s recommendation...

http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

I initially used the above to find a load that worked well for a 6.5 Creedmoor rifle (140 VLD) and subsequently succeeded with my 308 and 223 (both using Sierra bullets)

[JackEllis]

I develop loads by starting with charge weight, but I also have a specific bullet in mind. For hunting, I choose bullet types and weights based on what I plan to shoot. For varmints, I choose bullets based in part on suitability and in part on price since I plan on shooting a lot of them. I'll prep one or two rounds at .5 grain increments across the manufacturer's recommended range, shoot them, plot the muzzle velocities, then take a charge weight from the middle of a plateau in the plot that has acceptable muzzle velocity (faster is better with copper, but I'll use smaller, slower charges for varmints).

Once I have a charge weight that seems to work well enough, I experiment a bit with OAL. I'm after groups that are 1 to 1-1/4"inch, which is plenty good enough for large game and close enough for small game.

I'm sure you're going to get a bunch of different opinions (this is CGN after all).

[nedro]

I would develop a couple of repeatable good/precise loads and then play around with the jump.

I would do jumps in a maximum of 0.002 increments. Maybe even 0.001.

[choprzrul]

http://www.bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

I initially used the above to find a load that worked well for a 6.5 Creedmoor rifle (140 VLD) and subsequently succeeded with my 308 and 223 (both using Sierra bullets)

Thank you for that link. Very interesting. It reads, in part:

I do take issue with the testing depths based upon the premise that an accuracy band runs .030" to .040" wide. If the band is 30thou wide, centered at 0.030" off the rifling, it would range from 0.015" to 0.045". The testing ladder showing 0.010" and 0.050" would completely miss this accuracy band.

I'm thinking I might use this protocol:

0.010" off rifling start point
0.030"
0.050"
0.070"
0.090"
0.110"

If one of the above shows promise, I'll move 0.010" to either side and test again.

Just out of curiosity, once I find a sweet spot, I'll switch bullets/powder and see if the sweet spot is repeatable. The assertion being that every barrel has a particular sweet spot for jump regardless of bullet/powder choice.

Thoughts?

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[JackEllis]

Just out of curiosity, once I find a sweet spot, I'll switch bullets/powder and see if the sweet spot is repeatable. The assertion being that every barrel has a particular sweet spot for jump regardless of bullet/powder choice.

Thoughts?

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Let us know what you find out.

[choprzrul]

Let us know what you find out.

I hope you are the patient type.....I don't get in a hurry + the wife just decided to start remodeling the kitchen :-(

But.....I have no problem sharing results :-)

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[scotty99]

[choprzrul]

Yes, I do have a chrony and I record every shot placement and velocity in my PointBlank Ballistics program (I carry the laptop to the range with me).

To a degree I align with your velocity statement....but we must recognize that different powders have different pressure curves and will effect barrel harmonics. I generally use QuickLoad to find powders with a gentler pressure curve if possible. If it is a temperature stable powder, all the better.

An interesting thought comes to mind.....after finding an accuracy node at a particular seating depth, I wonder if one could adjust the headspace on a Savage to make changes that would ultimately allow a load that was particularly long to end up shorter, fit the magazine, and then set the 'jump' again? Hmmmmm....

[JackEllis]

I hope you are the patient type.....I don't get in a hurry + the wife just decided to start remodeling the kitchen :-(

But.....I have no problem sharing results :-)

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I'm patient when it comes to receiving gifts.

[LynnJr]

Choose the bullet you want to use first as it needs to work with your twist rate and the game you will be hunting.
Next pick a powder or two that work well with your combination.
Usually you would want 85% or more case fill and good velocity.
Primers are a tuning tool and very cheap so get several different ones and let the targets and chronograph decide which ones you will use.
When you first start out you are only looking for your powder charge so set the seating depth at its longest usable length which in your case is 0.010 off of the lands and leave it there.
You run the ladder test and the only thing you are looking for is vertical stringing. You pick the load or loads with the LEAST amount of vertical.
Now that you have a baseline for your powder charge you can vary the seating depth in 0.005 increments looking for a tightening up of the group's.
If your shooting VLD bullets follow there recommendations.
You should see patterns in your groups that point you to the best load for your combination.

[choprzrul]

Thank you sir for the thoughtful and intelligent response. It sounds like a logical protocol to follow.

In a nutshell....

1. pick my bullet
2. pick several powders
3. work thru load development searching for least vertical stringing
4. work thru seating depth to find accuracy node
5. smile throughout at the smell of burn gunpowder?

[jwfire25]

Yes, I do have a chrony and I record every shot placement and velocity in my PointBlank Ballistics program (I carry the laptop to the range with me).

What chrono you running?


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[choprzrul]

What chrono you running?


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ProChrono

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