Powder charge and seating depth

[6pakzak]

There's no single way that works best per se, if it works it works. Some processes are more deliberate though, and use fewer components. It seems like people earlier were talking about parts of the process and not the whole thing though.

I personally have been using:

1. Coarse seating Depth
   1. Typically start at 0.020" off, back out in 0.040" increment (if needed, honestly for comp rifles where I single feed anyways I typically start here and don't do coarse testing unless 0.020" off doesn't work)
   2. Include book COL in the test if it's way short
   3. Look for overall group, specifically horizontal dispersion
2. Charge Weight
   1. Typically shoot at 100-200-300 yards with a chrono
   2. Look for minimal vertical dispersion (hopefully maintaining horizontal)
   3. Look for chrono flat spots
   4. Look for overlaps between the two (change powder here if needed)
3. Fine tune seating Depth
   1. 0.002" to 0.004" increments around the coarse depth (depending on how tight the coarse depth was and far I need to go)
   2. Confirm fine tune seating doesn't wreck the vertical/muzzle stats
4. Tuner
   1. Pick a bad part of the ladder and reshoot to see if the tuner moves the groups
   2. If it does, take the tuned setting and run the load from #3
   3. Tweak if needed

There are different seating depth testing processes being discussed here potentially because there's not a lot of details being provided. As many methods as I can think of off the top of my head in in a minute:

1. Start at X.xxx" off and back up at 0.xxx"
2. Start at 0.000" or some jam and back off
3. The Berger "Big Jump" Method - 4 intervals that are 0.040-0.050" off, then fine tune
4. Start at mag length and back off 0.xxx"
5. Use book COL
6. Seat bullet base to neck junction
7. Seat to a cannelure

I got it between .3 and .4 groups now at 2.230, so maybe I should just work length up from there, I'm using 25gr 4166 cause I got it and ar doesn't seem to like it but fine in the bolt, maybe I I'm not gonna get much better out of factory gun, wanted to work up load cortina way but maybe I stumbled on it using seating before charge.

 

[6pakzak]

So finding the powder charge for a custom or semi custom gun would probably work pretty well if you start close to the lands since your final seating is probably gonna be close to that where as a factory gun is made knowing most people are gonna buy factory bullets which are seated further back so made to operate in that range or am I over thinking it. I think I will try what cortina says anyways and see where I end up.

 

[WildRose]

So finding the powder charge for a custom or semi custom gun would probably work pretty well if you start close to the lands since your final seating is probably gonna be close to that where as a factory gun is made knowing most people are gonna buy factory bullets which are seated further back so made to operate in that range or am I over thinking it. I think I will try what cortina says anyways and see where I end up.

The safest way is to always start well off of the lands to avoid pressure spikes.

I always start with bullets seated well short of mag length, find the most accurate charge and then if need be tweak the seating depth. It's the safest and shortest way I know of to get there.

 

[WildRose]

I got it between .3 and .4 groups now at 2.230, so maybe I should just work length up from there, I'm using 25gr 4166 cause I got it and ar doesn't seem to like it but fine in the bolt, maybe I I'm not gonna get much better out of factory gun, wanted to work up load cortina way but maybe I stumbled on it using seating before charge.

You aren't going to get substantially better than .3-.4 MOA groups with 99.9999% of hunting rifles no matter what you do.

 

[6pakzak]

You aren't going to get substantially better than .3-.4 MOA groups with 99.9999% of hunting rifles no matter what you do.

I think you're right, maybe tiny powder tweaking, it is a heavier barrel but it's still a factory gun. I think next gun will be barrel and action but I want to have a good system to use without guessing.

 

[WildRose]

I think you're right, maybe tiny powder tweaking, it is a heavier barrel but it's still a factory gun. I think next gun will be barrel and action but I want to have a good system to use without guessing.

If you are getting .3-.4MOA you're already beating what 99.999% of hunting rifles are going to get.

.1's, 2's, and 3's are bench rest territory.

 

[6pakzak]

If you are getting .3-.4MOA you're already beating what 99.999% of hunting rifles are going to get.

.1's, 2's, and 3's are bench rest territory.

Don't get me wrong, I tried a lot to get there and kept my rounds the most the same I could keep them, but I think I can learn more from these savages and I'm having fun working with them

 

[WildRose]

Don't get me wrong, I tried a lot to get there and kept my rounds the most the same I could keep them, but I think I can learn more from these savages and I'm having fun working with them

Well keep the law of diminishing returns in mind or you're just going to get frustrated burning up hard to replace components for little or no gain.

 

[6pakzak]

Well keep the law of diminishing returns in mind or you're just going to get frustrated burning up hard to replace components for little or no gain.

I get it, so far returns have been good, sometimes it feels like I hit the wall, but so far I've been able to move past it, looked at what I'm doing and see where I can improve with what I got, look at results and do something different and see what happens, groups are worse well that's the wrong way, and probably doesn't make sense to search for good group when I got it, waste of components. Doing the same thing time after time and expecting a different result makes you crazy

 

[WildRose]

I get it, so far returns have been good, sometimes it feels like I hit the wall, but so far I've been able to move past it, looked at what I'm doing and see where I can improve with what I got, look at results and do something different and see what happens, groups are worse well that's the wrong way, and probably doesn't make sense to search for good group when I got it, waste of components. Doing the same thing time after time and expecting a different result makes you crazy

Been there, done that, went nuts trying to chase fractional returns that made no practical difference in the field.

That's why I try to help others avoid doing the same things.

 

[cajun]

During the component shortage pre covid my methods changed to conserve resources. With a new rifle or bullet I load 10 or so rounds .3 grains apart at max mag coal or 20 off. I shoot at 100-300 yds depending on the rifles potential. I look for flat spots on the chrono which usually will mean consistent vertical down range. I also go to see what max pressure is. I will then load 3 for groups at the node closest to max. If that group looks good I may or may not play with the seating depth. I will then shoot a few groups to make sure the cold bore shots are consistent and there are no random flyers. I have found solid 1/2 to 3/4 moa loads in as little as 20 rounds. Now obviously you can do all sorts of tweaking burning components to make it better but for the hunting I do it's just not worth it. If I was shooting F class or benchrest and every little bit mattered that would be a different story.

 

[QuietTexan]

I used to do a powder node first using 20 thou off. Then I ran seating depth testing in 10 thou steps, then finer to tune it in.

Now I just start with 3 thou seating depth steps from either max mag length or the lands (alex wheeler method of finding lands).
I find the spot where I find 2-3 seating depth steps give me the best 100y groups. Then seat in the middle of that and move to powder testing, usually I go from mid-book up to one or two grains over book max in .2gr steps. Stop if I hit pressure.
Most times that will give me a couple nodes, depending on the rifles use I go one down from or the highest node.

I take the middle of the powder node and the middle and +2 thou of the seating depth node. I load up 10 of each and see how they group. Shoot each 10 shot group at 300y. Usually that nets me a solid load.

There are a few things to start with where I agree with Erik's videos. Start with brass in a blue box whenever possible, pick bullets known for consistency.

I meant to reference this in my longer post last night as another example of a rational, well thought out and complete process that shows both the seating and charge sides of the ledger This is more proof that multiple processes work.

I got it between .3 and .4 groups now at 2.230

You have arrived! Getting those consistently is why hand loading is so addicting. You know you can do it and nothing else will ever be quite as good, you'll never trust factory ammo quite as much, and everytime you shoot something you didn't load you'll always have this nagging feeling that a bad target was the ammo's fault.

So finding the powder charge for a custom or semi custom gun would probably work pretty well if you start close to the lands since your final seating is probably gonna be close to that where as a factory gun is made knowing most people are gonna buy factory bullets which are seated further back so made to operate in that range or am I over thinking it. I think I will try what cortina says anyways and see where I end up.

I've very rarely not found a good seating depth in what I'll call the first "major" depth interval of 0.000' to 0.050" off the lands. Doesn't mean I always use it, but when I've gone looking it's been there.

I'll qualify that by saying good means good, not perfect, and that I do believe all of Cal Zandt's evidence supporting Berger's recommendation of coarse seating intervals to identify multiple nodes - specifically wider, jump tolerant nodes that will work longer in high volume or fast firing schedules. A load that requires constant land chasing isn't in a wide enough node for what I'm asking it to do, and I should adjust seating to match the firing schedule I'm doing that makes the lands move like that.

And I also think that absolute precision doesn't necessarily sit in the middle of the widest node (or said another way, the most useable depth might not be the one that makes the smaller groups), so seating depth decisions are a constant trade off between finding the absolute smallest possible groups from a barrel and finding the most resilient load that works in the widest range of conditions. I've gotten some great loads, but they're super finicky and not practical. I've also accepted some loads y'all would call terrible because they do what they need to inside the constraints of that use.

For a hunting load I'll accept a sub-1 MOA group that shoots consistently in whatever conditions I'll be in over a load that shoots .3 MOA but I have to single feed, or it doesn't work over 50*, or I can't get the case wet, or if the bullet sets back in the mag it'll shoot way off, or if groups blow without my suppressor, etc.

Target loads worst that happens is I can't shoot the paper and I go home, those I can be a lot more precise with.

The safest way is to always start well off of the lands to avoid pressure spikes.

I always start with bullets seated well short of mag length, find the most accurate charge and then if need be tweak the seating depth. It's the safest and shortest way I know of to get there.

I'm not disagreeing with how you do this, if it works it works and it's at least as good as any other process that produces good results. I do somewhat disagree about having to start off the lands. I've started at and even into the lands just fine by using a powder charge from the low end of the chart and working up. I don't take a book COL load that's hot and seat it out and jam it, it's a deliberate process aimed at avoiding exactly what you said - a pressure spike. It also wasn't my first time with the chambering or powder, so I had experience to pair with Hodgdon's pressure data. For example if H4350 maxes out in a 6.5CM at 40.0gn compressed for 59k, below the 62k SAAMI max, and the starting load of 36.0gn is 49k of pressure, I'm not necessarily worried about creating a spike with a starting load at the lands. And if I am worried I can work out that way from the book COL, I don't have to start at a jammed seating depth if it's a new chambering, powder, bullet, etc. I've never had a problem, but that's because I'm conservative and careful about loading and not doing stupid things hopefully.

I admit I'm basically saying I can do this because I'm careful, so I'll add the disclaimer of "don't be stupid" to the random people on the internet who might read this

Don't get me wrong, I tried a lot to get there and kept my rounds the most the same I could keep them, but I think I can learn more from these savages and I'm having fun working with them

Along the lines of what Mike and I were saying about getting a load out of a node - you know you can produce a consistent .3-.4" group now, so have confidence in branching out and experimenting with different powders, seating depths, bullets, processes, etc because you know you can always road map back to a load that works well.

I'm a big believer in you have to climb the mountain yourself at least once, but once you're been there you know it's possible and (at least to me) it got a lot easier to do different things without any frustration. If something I was working on ended up sucking, no big deal just drop in a known load and make one little hole and feel good about going back to the drawing board.

I agree with the above that sometimes it's nice to have guidance on when to stop going down the rabbit hole, or be able to lean on people who've been there and seen something not work, but sometimes you have to buy the ticket and take the ride yourself.

 

[WildRose]

I meant to reference this in my longer post last night as another example of a rational, well thought out and complete process that shows both the seating and charge sides of the ledger This is more proof that multiple processes work.


You have arrived! Getting those consistently is why hand loading is so addicting. You know you can do it and nothing else will ever be quite as good, you'll never trust factory ammo quite as much, and everytime you shoot something you didn't load you'll always have this nagging feeling that a bad target was the ammo's fault.


I've very rarely not found a good seating depth in what I'll call the first "major" depth interval of 0.000' to 0.050" off the lands. Doesn't mean I always use it, but when I've gone looking it's been there.

I'll qualify that by saying good means good, not perfect, and that I do believe all of Cal Zandt's evidence supporting Berger's recommendation of coarse seating intervals to identify multiple nodes - specifically wider, jump tolerant nodes that will work longer in high volume or fast firing schedules. A load that requires constant land chasing isn't in a wide enough node for what I'm asking it to do, and I should adjust seating to match the firing schedule I'm doing that makes the lands move like that.

And I also think that absolute precision doesn't necessarily sit in the middle of the widest node (or said another way, the most useable depth might not be the one that makes the smaller groups), so seating depth decisions are a constant trade off between finding the absolute smallest possible groups from a barrel and finding the most resilient load that works in the widest range of conditions. I've gotten some great loads, but they're super finicky and not practical. I've also accepted some loads y'all would call terrible because they do what they need to inside the constraints of that use.

For a hunting load I'll accept a sub-1 MOA group that shoots consistently in whatever conditions I'll be in over a load that shoots .3 MOA but I have to single feed, or it doesn't work over 50*, or I can't get the case wet, or if the bullet sets back in the mag it'll shoot way off, or if groups blow without my suppressor, etc.

Target loads worst that happens is I can't shoot the paper and I go home, those I can be a lot more precise with.


I'm not disagreeing with how you do this, if it works it works and it's at least as good as any other process that produces good results. I do somewhat disagree about having to start off the lands. I've started at and even into the lands just fine by using a powder charge from the low end of the chart and working up. I don't take a book COL load that's hot and seat it out and jam it, it's a deliberate process aimed at avoiding exactly what you said - a pressure spike. It also wasn't my first time with the chambering or powder, so I had experience to pair with Hodgdon's pressure data. For example if H4350 maxes out in a 6.5CM at 40.0gn compressed for 59k, below the 62k SAAMI max, and the starting load of 36.0gn is 49k of pressure, I'm not necessarily worried about creating a spike with a starting load at the lands. And if I am worried I can work out that way from the book COL, I don't have to start at a jammed seating depth if it's a new chambering, powder, bullet, etc. I've never had a problem, but that's because I'm conservative and careful about loading and not doing stupid things hopefully.

I admit I'm basically saying I can do this because I'm careful, so I'll add the disclaimer of "don't be stupid" to the random people on the internet who might read this


Along the lines of what Mike and I were saying about getting a load out of a node - you know you can produce a consistent .3-.4" group now, so have confidence in branching out and experimenting with different powders, seating depths, bullets, processes, etc because you know you can always road map back to a load that works well.

I'm a big believer in you have to climb the mountain yourself at least once, but once you're been there you know it's possible and (at least to me) it got a lot easier to do different things without any frustration. If something I was working on ended up sucking, no big deal just drop in a known load and make one little hole and feel good about going back to the drawing board.

I agree with the above that sometimes it's nice to have guidance on when to stop going down the rabbit hole, or be able to lean on people who've been there and seen something not work, but sometimes you have to buy the ticket and take the ride yourself.

You aren't wrong in your method however especially for the novice loader it's always safest to start further off of the lands to avoid dangerous pressure spikes.

There are eccentricities in every chamber, be they factory or custom barrels and starting off too close can be a recipe for disaster.

We accept a certain level of risk as individuals when we reload and in many ways an even greater responsibility when advising others in how to load.

I'm always going to err on the side of caution for those reasons and because I damaged some guns and probably came very close to blowing one up many years ago failing to be cautious.

 

[Tech4]

Not that I would ever encourage anyone to do anything unsafe but keep in mind that all our load manuals pass through the hands of the liability lawyers before they go to print so their maximums are usually 10-15% reduced over what is actually safe.

Caveat: If you are loading into the lands very close or even jamming pressure spikes will be much greater with a given load than if you give the bullet some jump.

With the scopes, we have today what is gained by hot-rodding our ammo?