Reloading: A look at the Big Picture

[GetReal]

I contacted a major well reputed bullet manufacturer for some specific load data with a specific powder. They quickly emailed it to me (love this company) along with some recommendations for the process.

I emailed back , as a big picture clarification, as follows:
____________

To clarify....start on the lowest powder charge, and 0.015 off the lands. In 5 shot groups, work "out" or "away" from the lands in 0.015" increments, to find the small (est) grouping. Test +0.005 or - 0.005 for a better grouping. Once seating depth is settled, dial in powder charge for small (est) grouping, watching for signs of pressure, in 0.2 grain increments, while also testing muzzle velocity, for low (est) S.D. and E.S. Further testing may be done in 0.1 grain powder increments.

Does that sound right?

_____________

They replied:

"I would wait until I found my velocity accuracy node to do the CHRONOGRAPH stuff. But that's just me. The rest sounds good! "


QUESTION: What are your thoughts of my process. I've had good tho not perfect success with it. It prolly takes me about 100 - 150 rounds to find a re-re-repeatedble load that groups good with good SD / ES.

 

[HTSmith]

I'm far from an expert but it would be good to know what game you are shooting and what cartridge. For a hunting round that sounds about right to me. For target use, I'd say the space from .015 off to .015 in is where many rifles shoot their best--you aren't testing there if I read right.

 

[GetReal]

I'm far from an expert but it would be good to know what game you are shooting and what cartridge. For a hunting round that sounds about right to me. For target use, I'd say the space from .015 off to .015 in is where many rifles shoot their best--you aren't testing there if I read right.

Yer reading it right, far as I can tell. I'm told some cartridges like being a little jammed into the lands. I suspect no major bullet / powder manuafcturer will recommend this due to liability issues.

The relaoding manual this company publishes maxxes out its powder loads WELL below where most everyone I know shoots.

 

[JASmith]

also - - .2 gr in a 25 gr charge looks like 0.4 gr in a 50 gr charge.

So, the advice might be couched in terms of .1 gr for case capacities less than 25 gr, 0.2 gr increments for 26 to 50 gr cases, 0.3 gr for 51 to 75 gr capacities, and so n.

 

[jelenko]

In this video Litz proposes [he says it's the approach he takes] to find the powder charge where pressure signs start to show, back off 1/2 grain and do a seating dept test.
He says as long as the rifle is put together well, you'll get a 1/2 MOA load.

He is talking about PRS, not BR.

The next time I do load development, this is what I'm going to do. [Note: My rifle is an AR set up as a 'match rifle'. But, if the approach works, it should work for an AR]

 

[big5ifty]

My method :

Pick a primer. Pick a powder. Pick a bullet. Have good brass.

Start with seating depth 10 thou off the lands.

6 loads 0.3 grains apart, 3 rounds per load. Decide what the max load will be, and work down from there.

If your cartridge can use Sta-Ball and you can find Fiocchi primers, you're off to an excellent start.

Shoot over a chrony, you're looking for the lowest ES.

You may need to repeat this a few times with different powders and primers to get a low ES. 15 fps is very good, 10 and under is excellent. If you can achieve 25, it's a good start.

That's 18 rounds per combination of powder and primer. If you're not sure where to start, copy the components others are using with good results. Not from random people on the internet - find info from well known competition shooters who shoot your caliber.

Once you have the low ES, load up 3 rounds each at 10 thou off the lands, 12, 14 to 18. That's five loads to shoot five groups at 100.

Best group wins.

There are a couple of points to note :

1. You have to have good brass. Good brass is Norma or Lapua. Mileage will vary with other makes.
2. You have to have good bullets. Berger is a good bullet, so is Nosler. Others may be good, these I know.
3. It's a good idea to run these tests with a properly clean barrel.

Addendum :

Most importantly, if you can't shoot a good group, you will never know if you have a good load.

 

[big5ifty]

To clarify....start on the lowest powder charge, and 0.015 off the lands. In 5 shot groups, work "out" or "away" from the lands in 0.015" increments, to find the small (est) grouping. Test +0.005 or - 0.005 for a better grouping. Once seating depth is settled, dial in powder charge for small (est) grouping, watching for signs of pressure, in 0.2 grain increments, while also testing muzzle velocity, for low (est) S.D. and E.S. Further testing may be done in 0.1 grain powder increments.

Does that sound right?

What you are effectively doing is load tuning by seating depth for the lowest powder charge.

Then you change the load, but continue using the lowest powder charge seating depth.

When the powder charge is materially different, the optimal seating depth changes with it.

You may get better results quicker, in fewer iterations, if you switch finding the seating depth first to finding a good ES first.

 

[FeMan]

Your approach sounds fine. The seating depth adjustment is something I would tighten up though.

I start with a quick powder ladder looking for max velocity/pressure. Once I see that I dial it down a little and go to seating depth. In my experience, seating depth is the single most determinant factor in group size. I use 0.003 increments rather than 5k, especially when I am that close to the lands. Once I get a seating depth I like I go back to powder and see if velocity changes improve things.

The chrono readings are simply an input into my Kestrel for me. I have loads that shoot 0.1 moa (or less) that have SDs of 15 or so. The target looks amazing so I turn the chrono screen off and go to shooting x's.

 

[GetReal]

When the powder charge is materially different, the optimal seating depth changes with it.

Not sure what you consider "materially diffferent" but they were talking within a single caliber, with maybe a 10% max variance in lowest vs. highest charge.

They were saying once you've settled on a searing depth, it should hold for the range of powder charges e.g. from 24.0 grains to 26.0 grains.

 

[mikecr]

When the powder charge is materially different, the optimal seating depth changes with it.

I disagree. Seating and powder are independent.
Coarse-Optimal seating holds, regardless of powder changes.
That's part of why I do coarse seating, and primers, before I even begin to work up a powder load.
Now there is the fine group shaping available with seating. That will tweak seating a tiny bit from one load to another. But this can be done just the same with neck tension adjustment (through sizing LENGTH).

As far as putting best barrel tune on top of best powder burn, the only way I can think of to ensure that is with use of a barrel tuner.
It is common that best overall accuracy is not reached at lowest ES. This is because barrel tune slightly overrides powder tune (on target). This is one of the reasons that OCW testing does not get you to cutting edge best accuracy.
Primers/primer striking, and seating are just prerequisite to tuning, and not actual tuning in themselves.

IMO, it is a mistake to attempt tuning with primers or seating.
Best to use powder (right to the kernel) and neck tension (via sizing length) for tuning.

 

[PracticalTactical]

If I'm reading the Op correctly it sounds like you are talking about testing multiple variables at the same time. It's always easier to slow down and test one thing at a time starting with powder charge.

Obviously the last thing you want is a hot load so work your way up to find where that is, then stay below that charge weight. I would do this with a seating depth somewhere around the 0.015" off the lands value as suggested but that is just a ball park value.

Then with the same seating depth, start looking for a charge weight you like, or more importantly that the chronograph likes.

Once you have the charge dialed in, start testing seating depth from a soft jam and working your way back from there to find where you get the most consistent velocity spreads with the best groups.

In my experience, there is an obvious result you can expect when changing seating depth...

Too far from the lands will provide poor accuracy and wide velocity spreads.

Moving forward, you can expect the groups to shrink and velocity spreads to tighten up.

Once you start seating too far forward, everything starts going the other way again and fast.

I like to be on the long end of this seating depth node because it anticipates throat erosion.

As for the question about jam vs jump, I would suggest you consider the five whys of root cause analysis... Just keep asking why, then why that etc until you get to the bottom of it.

What does jamming the lands really do?

It stops pressure from leaking around the bullet and it centers up the front of the bearing surface to the center line of the bore.

That still leaves the butt end of the bullet hanging in the breeze, so how do you control that little bit of wiggle?

You have three controlling factors... the free bore diameter clearance in your chamber, free bore length, and the neck clearance in the chamber. If those are optimized, then the bullet will always start into the rifling on the correct axis.

If the bullet is so well guided into the rifling that it has no angular offset, then you can expect both accuracy and a low velocity spread by virtue of consistent resistance in engraving the bullet into the rifling.

So to address the question as to why one shooter believes one thing is best and another follows a different path, you have to consider the the full picture of bullet, brass and chamber. One solution does not apply to all variations and each has to find his own balance based on his control of those variations.

 

[GetReal]

If I'm reading the Op correctly it sounds like you are talking about testing multiple variables at the same time. It's always easier to slow down and test one thing at a time starting with powder charge.

They were saying to start with the lowest powder charge , leaving it unchaged for the entire seating deth testing. Then test seating depth ONLY until you find what you regard as optimal before testing / changing anything else.

 

[PracticalTactical]

They were saying to start with the lowest powder charge , leaving it unchaged for the entire seating deth testing. Then test seating depth ONLY until you find what you regard as optimal before testing / changing anything else.

Well that's one way to go, but I have tracked my POI change more radically based on powder charge changes than by seating depth.

Barrels have oscillation nodes and you want the bullet to exit while the barrel is at one end of that oscillation node or the other.

 

[mikecr]

The lowest powder charge recommendation is not really for safety. It's to ensure that you can see the result of seating changes without interference from a powder node.

For every aftermarket barrel I've tuned, seating is by far the single biggest affect. No amount of powder change affects grouping like worst seating. Similar with primers. If you're using the wrong primer, you can reach a 'good' load, but you can forget reaching 'best' with it. Ain't gonna happen.

A major problem we have here is that almost nobody does actual full seating testing, and does it correctly.
Instead, people pull some initial seating out of their butts, and go right to fine tweaking from a powder node.
And yeah, when you fine tweak seating far enough, that powder timing is affected, and you're just chasing tail at that point.

 

[GetReal]

The lowest powder charge recommendation is not really for safety. It's to ensure that you can see the result of seating changes without interference from a powder node.

Good info....thanx !!

 

[GetReal]

Well that's one way to go, but I have tracked my POI change more radically based on powder charge changes than by seating depth.

Barrels have oscillation nodes and you want the bullet to exit while the barrel is at one end of that oscillation node or the other.

All I can say is the company I was talking to is the 800 lb gorilla in the industry. Others have told me the order doesn't matter, whether you do seating depth or powder charge.... as seating depth will remain constant thru a 10 - 15% powder charge range.

That said, I've settled on powder charge first and then dialed in seating depth and found that to work. And I've heard others say powder charge (which determines velocity) is the major factor where seating depth is fine tuning.

 

[mikecr]

Yep,, that +100yr notion still prevails.
Yet, in all that time, we have not reached consensus on anything.. No credible method has been settled on.

I watched on these forums for ~20yrs, all the gorillas claiming that VLDs had to be [in the lands] to shoot.
Well, the root cause of their utterly wrong declarations was that they NEVER actually did full seating testing.
None of them, not once.
What were they doing? No more than same as done for the past century..

 

[GetReal]

Yet, in all that time, we have not reached consensus on anything.. No credible method has been settled on.

Truer words never spoken.

 

[BoydAllen]

What rifle, and caliber? If a bolt action, and you are not concerned about magazine length, this is what I have done for years.

I seat the bullet so that there are there are very light marks, about half as long as wide.
I do a powder charge/pressure test, one shot per charge, .3gn increments, .5 for 22-250 and larger. I do this on a morning when the wind is easy, at 100 yards shooting over a couple of flag using the same target, and hold, shooting all shots in the same wind condition. At the end of my test, I will know what my top charge weight is for my rifle (that day's ambiennt conditions), based on bolt lift, and I will usually see some clustering. I pick the best looking cluster, load a three shot test with the middle or average charge weight, and if that looks good, make any small charge adjustment that the group shape suggests, and then play with seating depth, usually staying in the rifling, with changes of no more than .002, remembering that there are depth nodes, so I do not assume that if the group gets worse that I should stop moving in that direction. My neck tension starts out at .002 but may be played with later, depending on the groups. I don't bother with bad barrels or unbedded actions. I have excellent rests and bags and access to benches that do not move at all. Using this procedure with a likely powder and good bullets, I can usually come up wiht a good load in a couple of hours, loading at the range. If velocity is a consideration, I set up a chronograph and do all of my shooting over it. It seems to me that many are attracted to the idea that this should be a lot more complicated than it really has to be.

 

[PracticalTactical]

The lowest powder charge recommendation is not really for safety. It's to ensure that you can see the result of seating changes without interference from a powder node.

For every aftermarket barrel I've tuned, seating is by far the single biggest affect. No amount of powder change affects grouping like worst seating. Similar with primers. If you're using the wrong primer, you can reach a 'good' load, but you can forget reaching 'best' with it. Ain't gonna happen.

A major problem we have here is that almost nobody does actual full seating testing, and does it correctly.
Instead, people pull some initial seating out of their butts, and go right to fine tweaking from a powder node.
And yeah, when you fine tweak seating far enough, that powder timing is affected, and you're just chasing tail at that point.

Interesting thoughts Mike...

I do not disagree that seating depth affects group size, but so does a bullet leaving the barrel in a bad place in the harmonic which is affected by powder charge. So in this sense the powder charge is going to either positively or negatively affect the group size and overall location on the target.

Certainly both jump and powder charge interact to form the group.

So this is a what comes first, the chicken or the egg kinda thing.

Change the seating depth and it will affect group size, but changing the powder charge changes the group size and location.

Depending on how heavy the barrel is, mileage will vary certainly.