Powder charge or seating depth first

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Leatherstocking

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Wanting to develop a new hunting load in 308Win.
150 grn Barnes TTSX, IMR 4895, new Lapua brass, CCI 200 LRP
Should I go with a minimum powder charge and try adjusting seating depth?
 
I know people say always start at minimum. I generally start at just below the middle powdercharge wise and seat the bullet 10-15 thou shirt of the lands if the mag is long enough. Keeping in mind that copper bullets are longer than lead for their weight so have more bearing surface against the rifling. I found I had to reduce my powder charge 2 grains in the 30-06 when switching to the same weight copper bullet from lead.
 
I set my seating depth .025" from lands with lead-based bullets and .050" with copper bullets.
I haven't needed to change those unless the COAL is longer than the mag length. If that's the case I seat them as long as possible to fit the mag.
Other than that all load development is done with powder selection and charge weights.
 
With lead core bullets I start at 20 thou off the rifling and develop the powder charge. Then I play with seating depth to see if anything improves.

With a copper bullet, you want more jump than 20.
 
first seat bullet at factory/manual recommended depth.

research online for known accuracy nodes
start 0.5 grain lower, end 0.5 grain higher, 0.2-grain increments, 3 round each.
stay away from max loads, wears out brass and barrel, and typically not worth it for non-competition use.

use magneto/labrador/chrono to measure muzzle velocity, shoot 3 separate times, 1st time lowest to highest load, 2nd time highest to lowest load, 3rd time lowest to highest load.
cool off the barrel between each run.

If you don't have anything to measure the muzzle velocity, shoot at 300 yards and do 3 runs. video record the target. note the vertical positions to determine relative muzzle velocity.
find the load with the most consistent muzzle velocity, (small extreme spread, also minimal velocity change with powder weight) plot a graph makes it easier.

tweak bullet seating depth to find the tightest group.

typically, tweaking powder weight alone gets you under 1 moa.

remember to record muzzle velocity at different temperature or altitude/pressure for your DOPE book.
 
xingyc said:
first seat bullet at factory/manual recommended depth.

research online for known accuracy nodes
start 0.5 grain lower, end 0.5 grain higher, 0.2-grain increments, 3 round each.
stay away from max loads, wears out brass and barrel, and typically not worth it for non-competition use.

use magneto/labrador/chrono to measure muzzle velocity, shoot 3 separate times, 1st time lowest to highest load, 2nd time highest to lowest load, 3rd time lowest to highest load.
cool off the barrel between each run.

If you don't have anything to measure the muzzle velocity, shoot at 300 yards and do 3 runs. video record the target. note the vertical positions to determine relative muzzle velocity.
find the load with the most consistent muzzle velocity, (small extreme spread, also minimal velocity change with powder weight) plot a graph makes it easier.

tweak bullet seating depth to find the tightest group.

typically, tweaking powder weight alone gets you under 1 moa.

remember to record muzzle velocity at different temperature or altitude/pressure for your DOPE book.
Click to expand...

The seating depth in the book is not a "recommendation". It is just a note of the depth they used for their rifle. A Remington needs a longer round than a Winchester, for example, because they use different chamber reamers. (Remington have much deeper throats). If you are loading for a new Savage, the "book" OAL might put the bullet hard into the rifling. Not good.

I don't care what Hornady used. I am loading for my rile - and I start 20 thou off.
 
Um first off, if it is for hunting, it has to fit in the mag. So You find the powder charge it likes in the size that fits the mag and then tweak it to the best group.
All these recommendations of X's thou off the lands means chit if it gets stuck in the mag.
Just my humble opinion.
 
To add on tigrr's post.

A method, which I MAY switch to, is finding the powder charge first with the lowest deviation , that is your most consistent burn for that barrel.

Then you work away from that seating in small increments to find the depth/width of your accuracy node.It could be a node that has acceptable accuracy for a run of depth's so you pick the deepest seating depth in that node then as the rifle loses accuracy you can seat out farther to to get closer to the lands again as the throat wears to maintain your original or close to original accuracy.

Erik Cortina has videos on it and I did a VERY brief summary and hopefully I got it right.He goes into great detail about it but it isn't exactly complex and to me the method makes sense.

Again too many ways to skin a cat but that is for precision rifles.

OR

For acceptable hunting accuracy I'd pick a functional seating depth and work up 3 shots groups from minimum to maximum and settle on one that is consistently in the MOA range.The Barnes do always seem to shoot, I load for many others that use them,I just don't use them myself but they do shoot most times.
 
xingyc said:
first seat bullet at factory/manual recommended depth.

research online for known accuracy nodes
start 0.5 grain lower, end 0.5 grain higher, 0.2-grain increments, 3 round each.
stay away from max loads, wears out brass and barrel, and typically not worth it for non-competition use.

use magneto/labrador/chrono to measure muzzle velocity, shoot 3 separate times, 1st time lowest to highest load, 2nd time highest to lowest load, 3rd time lowest to highest load.
cool off the barrel between each run.

If you don't have anything to measure the muzzle velocity, shoot at 300 yards and do 3 runs. video record the target. note the vertical positions to determine relative muzzle velocity.
find the load with the most consistent muzzle velocity, (small extreme spread, also minimal velocity change with powder weight) plot a graph makes it easier.

tweak bullet seating depth to find the tightest group.

typically, tweaking powder weight alone gets you under 1 moa.

remember to record muzzle velocity at different temperature or altitude/pressure for your DOPE book.
Click to expand...

Very good advise..thats the way to do it.
 
There are different ways for doing it and they are all valid as long as the final result is an accurate and consistent load.
I realized after reading these posts that what I do is a combination of all the methods described above. I am a hunter not a benchrest shooter. My goal is 1 moa or better.
I first decide what bullet to use. I consult then the loading data from the manufacturer. I always start with the primer they indicate. If they have a 'most accurate load', I will use it as a reference. I load +/- 1 grain around it in groups of 3 and 0.5 increments. If there is a 'PET load' for a caliber I do the same. If there is none of the above, I start with max load minus 2 grains and increments of 0.5 grain. I measure the COL in my rifle. My original seating depth is 30 thousands less than OAL except when the magazine can not take it in which case I start with max magazine length.
Then I head to the range with 5 loads of 3. I chronograph all my shots. I watch for speed and groupings. Quite often with this method I have sub moa groups with low SD. I am a hunter, so I am happy with that. Usually for me this is the end of load development. A second situation is when I have low SD with big group, this is when I work on seating depth, by deepening 10 thou each time. A third situation is big SD with a reasonable group. In this case I first try different primers. This can make a big difference. And if all that does not work I try tweaking the 'best' powder charge up or down by 0.5 grain again. This has worked every time for me in all my rifles. As a result, I do not shoot any load that is above one moa. Nosler and Sierra are the easiest to load for as they always mention their most accurate load with most accurate powder. With Nosler, I had sub-moa grouping using one load only (their most accurate), it worked each time in my Sako 270 win and Tikka 6.5x55.
I find Lapua cases to be the best, followed by Norma and Nosler. I have also used Hornady, Federal, Winchester and PPU.
 
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Don't waste your time playing with different seating depths. I like close to 1 caliber of bullet shank/neck contact, .030" off the lands or more (.050 with Barnes monometal) and tune accuracy with powder charge.
 
Pointy, VLD type bullets - start at 10 thou off the lands

Roundish ogives - start at 20thou off the lands.

Adjust powder charge.... if the set up will shoot, you will see very good results out of the gate. I rarely play with seating depths anymore

Jerry
 
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