Load development: Seating depth VS Charge weight

[Lonewolf74]

Ok so just something I've been thinking about. I typically start out my load development with all my rounds seated to touching lands then once I find the most accurate charge I test different seating depths working back from touching lands.

But I have heard a few people say they do it the other way around.

So my question is what is your process for load development, charge weight or seating depth first?

If you start with seating depth how do you go about it?

 

[Trnelson]

I suppose it's kind of dealers choice. Especially if you are working up as you are supposed to. Generally I have the best luck testing seating depths with minimum charges to find what the rifle shoots best. It also gets me a safe baseline of how that barrel compares to known book data. I usually start at ~0.050" off the rifling and work outward at 0.005" incriments. Once I have the depth pretty well figured out I set my seating die and I break out the magnetospeed. I start adding powder usually between 0.2g incriments in smaller and shorter cases and 0.5g in larger cases until I find the best safe velocity that the rifle delivers. Then I start working on primer changes and very small seating changes and lastly small powder charge changes to make sure the load is delivering the best accuracy it can. Along with best safe velocity and the lowest SD possible. There's certainly more than one way to skin a cat...

 

[coyotezapper]

If you are using a chronograph then charge weight first looking for velocity flat spot. Once flat spot is found then adjust seating depth.

If no chronograph then do seating depth first.

 

[Lonewolf74]

If you are using a chronograph then charge weight first looking for velocity flat spot. Once flat spot is found then adjust seating depth.

If no chronograph then do seating depth first.

By flat spot do you mean a point where velocity doesn't rise or rises very little with powder increases?

 

[coyotezapper]

By flat spot do you mean a point where velocity doesn't rise or rises very little with powder increases?

Yes. This is where you want to be for a good consistent load. These loads will give you a wide powder charge window and usually a wide seating depth window also.

 

[Rich Coyle]

Charge weight first.

 

[Doc88]

Long range load development at 100 yards. | Shooters' Forum

Found this to be a very interesting read.

 

[RockyMtnMT]

Long range load development at 100 yards. | Shooters' Forum

Found this to be a very interesting read.

I think this is a very good load development practice. I do a couple of things differently. I do not load touching the lands as it will create higher pressure and I do not like it for hunting. Once had a primer failure and when I ejected the bullet stayed in the lands and I lost a giant mulie. I load and shoot up in charge weight 1 shot at a time watching the group and the vel as well as pressure signs. Depending on the size of the cartridge I will do this in 1 or .5g increments. Once I find the upper end then I will shoot several over the chronograph to verify that ES is good. Then I will shoot for group and make seating depth adjustments shorter until group tightens up. In adjusting seating depth I will not shoot a 3rd shot if the first two did not group. No point in continuing the group if it starts out poor. It won't get better unless it was shooter error. I don't see any point in wasting the resources. Once you find the group that is tightest then you can work on finer seating depth adjustments. At this point the rifle should be shooting quite well and would probable need 300y or more to be able to see the changes.

When it comes to hunting accuracy it may not be worth the extra rounds to shave off a fraction of an moa. That you have to ask yourself.

With our Hammer Bullets we very rarely ever make a seating depth adjustment and are able to shave dozens of shots off load development. We are usually done finding our top end load in 6-8 shots then another 6-8 shots to verify velocity and zero. If we are not happy with the first powder we try it may take an extra 6-8 shots to work another powder. I like loads that are as close as we can get to full load density at top end. We only switch powders if we run out of case capacity before pressure or if pressure comes too soon. Rarely we will switch powder on the work up if the group as we work up is not consistent.

That is how we do it. If we were smart we would tell people to shoot the method that takes hundreds of shots as we would sell more bullets. I would rather use the extra bullets shooting something more fun than paper.

Steve

 

[Mikecr]

I do a version of Berger's seating testing(full) while fire forming brass.
Then with coarse best seating, and stable capacity brass, I move to powder development(ladder), then a final tweak of seating(just for group shaping).

 

[BallisticsGuy]

I think this is a very good load development practice. I do a couple of things differently. I do not load touching the lands as it will create higher pressure and I do not like it for hunting. Once had a primer failure and when I ejected the bullet stayed in the lands and I lost a giant mulie. I load and shoot up in charge weight 1 shot at a time watching the group and the vel as well as pressure signs. Depending on the size of the cartridge I will do this in 1 or .5g increments. Once I find the upper end then I will shoot several over the chronograph to verify that ES is good. Then I will shoot for group and make seating depth adjustments shorter until group tightens up. In adjusting seating depth I will not shoot a 3rd shot if the first two did not group. No point in continuing the group if it starts out poor. It won't get better unless it was shooter error. I don't see any point in wasting the resources. Once you find the group that is tightest then you can work on finer seating depth adjustments. At this point the rifle should be shooting quite well and would probable need 300y or more to be able to see the changes.

When it comes to hunting accuracy it may not be worth the extra rounds to shave off a fraction of an moa. That you have to ask yourself.

With our Hammer Bullets we very rarely ever make a seating depth adjustment and are able to shave dozens of shots off load development. We are usually done finding our top end load in 6-8 shots then another 6-8 shots to verify velocity and zero. If we are not happy with the first powder we try it may take an extra 6-8 shots to work another powder. I like loads that are as close as we can get to full load density at top end. We only switch powders if we run out of case capacity before pressure or if pressure comes too soon. Rarely we will switch powder on the work up if the group as we work up is not consistent.

That is how we do it. If we were smart we would tell people to shoot the method that takes hundreds of shots as we would sell more bullets. I would rather use the extra bullets shooting something more fun than paper.

Steve

For hunters, ^^^ this. Using that method has saved me tons of powder/primers/bullets/time.

 

[Doc88]

When you're shooting 1 shot at the time going up in powder charge, what are you settling on as an ideal powder charge? Is it the 2-3 shots that sort of group together. Always looking to learn. Thanks.

 

[Rich Coyle]

When you're shooting 1 shot at the time going up in powder charge, what are you settling on as an ideal powder charge? Is it the 2-3 shots that sort of group together. Always looking to learn. Thanks.

Two things. 1. Maximum charge without any pressure issues. 2. At least three close together.

 

[coyotezapper]

I think this is a very good load development practice. I do a couple of things differently. I do not load touching the lands as it will create higher pressure and I do not like it for hunting. Once had a primer failure and when I ejected the bullet stayed in the lands and I lost a giant mulie. I load and shoot up in charge weight 1 shot at a time watching the group and the vel as well as pressure signs. Depending on the size of the cartridge I will do this in 1 or .5g increments. Once I find the upper end then I will shoot several over the chronograph to verify that ES is good. Then I will shoot for group and make seating depth adjustments shorter until group tightens up. In adjusting seating depth I will not shoot a 3rd shot if the first two did not group. No point in continuing the group if it starts out poor. It won't get better unless it was shooter error. I don't see any point in wasting the resources. Once you find the group that is tightest then you can work on finer seating depth adjustments. At this point the rifle should be shooting quite well and would probable need 300y or more to be able to see the changes.

When it comes to hunting accuracy it may not be worth the extra rounds to shave off a fraction of an moa. That you have to ask yourself.

With our Hammer Bullets we very rarely ever make a seating depth adjustment and are able to shave dozens of shots off load development. We are usually done finding our top end load in 6-8 shots then another 6-8 shots to verify velocity and zero. If we are not happy with the first powder we try it may take an extra 6-8 shots to work another powder. I like loads that are as close as we can get to full load density at top end. We only switch powders if we run out of case capacity before pressure or if pressure comes too soon. Rarely we will switch powder on the work up if the group as we work up is not consistent.

That is how we do it. If we were smart we would tell people to shoot the method that takes hundreds of shots as we would sell more bullets. I would rather use the extra bullets shooting something more fun than paper.

Steve

Very good advice.

 

[coyotezapper]

When you're shooting 1 shot at the time going up in powder charge, what are you settling on as an ideal powder charge? Is it the 2-3 shots that sort of group together. Always looking to learn. Thanks.

Flat spot in velocity gain.