vary powder charge first or seating depth first?

Varmit

Varmit

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I've always varied my powder charge first and when I found a good group at the highest I then different seating depths to try and improve the groups I was getting.
I found these comments below on another discussion forum wondered if anyone here does it the other way around, finding the best seating depth first.

Bryan Litz, chief ballistician at Berger, talks about seating depth during load development: "In general, the seating depth of a particular bullet in a particular rifle tends to be more static than what powder charge will work best. In other words, it's probably best to start with a low to medium powder charge and find the best seating depth. Then, using that established seating depth, start working on changes in powder charge."
 
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Varmit said:
it's probably best to start with a low to medium powder charge and find the best seating depth. Then, using that established seating depth, start working on changes in powder charge.
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Hadn't thought of that. Awesome.
 
I have always set the depth of the bullet as close to the lands as possible until it is within .005 in of touching. In bench rest rifles, the bullets are usually touching the lands. Once this has been done, I start with the powder adjustments.

One thing to understand, when a chamber is sloppy it's a pretty good indication finding the sweet spot with full length resized ammo very likely won't happen. That's when you start neck resizing only and start checking to see if your hand loads are true to center.

Recently a new hand loader came over with his new "custom" rifle. His uncle in Ontario had put it together himself as a project. He did a pretty good job over all but the reamer he used was oversized. Not by a lot but enough to cause accuracy issues. It also had about .250 in of freebore. Another recipe for inaccuracy if the chamber isn't dead on true to center and tight. This is a normal situation for some of the old Weatherby chamberings. The saving grace was the leade to the lands was tight. Even then, until we only partially sized the necks of the cases we loaded, the accuracy came into reasonable parameters.

There is much more to accuracy than bullet depth or powder charge.
 
Depends on what kind of load you're after. Mucking around with the seating depth is usually not done for hunting loads because the degree of accuracy target shooters want isn't required.
 
"I've always varied my powder charge first and when I found a good group at the highest I then different seating depths to try and improve the groups I was getting. "

Me too.

Some bullets do best when touching the rifling, some do better about 20 thou off the rifling. In my experience, most do better off the rifling.
 
I guess if you're changing the volume by adjusting the seating depth, you're also changing the pressure dynamics of the burn. Saves energy to tune the powder once instead of twice.
 
sunray said:
Depends on what kind of load you're after. Mucking around with the seating depth is usually not done for hunting loads because the degree of accuracy target shooters want isn't required.
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Once a target shooter always a target shooter. Accuracy becomes an addiction.
 
Always play with one variable at a time. With my f-class load I always start of 10 or 20 thou of the lands depending on the bullet so that extraction isn't a issue. Vary the charge weight using the same seating depth, find your OCW load or ladder test node. Then play around with the seating depth to find the optimal seating depth. I usually test 5 jam, 5 off, 10, 20, 30 to see which ends up tightening up my group from my decided charge weight.

The thing is with Litz is he loads his match loads pretty hot from what I hear through the grape vine, hot enough that he has throw his brass out after one or two firings.
 
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Ganderite said:
"I've always varied my powder charge first and when I found a good group at the highest I then different seating depths to try and improve the groups I was getting. "

Me too.

Some bullets do best when touching the rifling, some do better about 20 thou off the rifling. In my experience, most do better off the rifling.
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this
 
Both changes effect pressure , which one do you want to play with is the big question.

Personally , I would look at use/purpose of that rifle first.Must the rounds fit a mag? Is it single feed?Semi-auto? Target rifle? Manufacturers recommendations for seating depth?

I go with a seating depth first and base that on my usage of that rifle.

Once I get my depth figured and confirm function I will do my powder tests.Typically for most real world use and needs no further tweaking is required.

If wanting to squeeze every smidge of accuracy then yes , play a bit with the depth.Mind you at this stage you are dealing with rifles that aren't exactly SAAMI minimum machines.
 
Will not go into all the ins and outs but bullets don't care where they are relative to the lands - as long as they bullet engrave the rifling BEFORE leaving the case neck. Tested all shapes off, near, jammed, etc.

I seat for proper function and wrt F class, extraction of the loaded rd in case there is a cease fire.

Seating depth, powder charge, primer are just a few ways that we tune the kaboom to suit the harmonics of the barrel. As long as we hit the right "note", how you vary the options is entirely up to you.

So I use powder to tune my ammo and use very precise quality scales to ensure I am holding my powder charges to a high degree of accuracy.

I feel it is easier to hold powder charge precise then trying to control seating depth for an object with varying shape.

Jerry
 
I've always worked up loads using powder charge as my major variable, and only fiddled around with seating depth as a secondary factor (if at all). I do always try to seat bullets as far out as possible, though; just seems like a very good general rule to follow.

Maybe I'll do some more work with seating depth in the future...
 
I fired some 270 win all loaded with 58 grains of H4831 and 130 gr Nosler B Tips at varying seating depths. At 80 thou setback I got a 5/8" group at 100 yds which was way better than any of the others which were at 20, 60, and 100 back from the lands. Featherweight M70. I am going back to range to try it some more to make sure it is repeatable and to go up with the charge to see if it holds at higher velocities.
 
If its a hunting rifle I will always run the cases through the mag and check for feeding at different lengths or at least the length I intend to shoot. Some rifles just wont feed right if the COL is to long or short. IF it feeds all lengths fine, if not I don't even bother testing for accuracy at the problematic lengths. This step is often overlooked, to bad because this is an important part of tailoring your reloads to your hunting rifle.
 
Republic of Alberta said:
If its a hunting rifle I will always run the cases through the mag and check for feeding at different lengths or at least the length I intend to shoot. Some rifles just wont feed right if the COL is to long or short. IF it feeds all lengths fine, if not I don't even bother testing for accuracy at the problematic lengths. This step is often overlooked, to bad because this is an important part of tailoring your reloads to your hunting rifle.
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I near drove myself crazy while trying to make a hunting rifle into a target rifle. Hey it is very accurate hunting rifle but its not a target rifle. I can shoot bugs at a hundred with it but the rounds won't fit in the magazine.
 
DFB Plinker said:
I near drove myself crazy while trying to make a hunting rifle into a target rifle. Hey it is very accurate hunting rifle but its not a target rifle. I can shoot bugs at a hundred with it but the rounds won't fit in the magazine.
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with mine 80 thou back is fairly short like factory ammo
 
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