Powder charge and seating depth

[cajun]

I like Eric. His videos are good. He is a competition shooter shooting 1000 yds where every little thing matters. If your load shoots 1/2 " groups at 100 but has a 75 es at 1000 it's going to suck just due to vertical caused by the velocity spread. Thats why these guys do what they do. If your a hunter shooting critters with a 10" kill zone at 500 yds es matters a lot less. Cold bore repeatability and the difference between cold bore shots and subsequent shots may have more impact. Weather you do powder first or seating depth first. You should wind up in the same place. Es is going to be determined by powder charge accuracy and neck tension consistency.

 

[Mikecr]

I can't imagine someone settling with a 75fps ES.
But at normal velocity spreads, neither accuracy nor precision directly follow ES.
It's a combination of barrel node and powder node thing..

 

[SSG Graybush]

I usually seat the bullet for what it calls for from the book or bullet makers website, then I start low on charge and work up till I get good groups but what if my es is high say 30 fps it would mean my load is not good cause the high es. So Cortina says to start with seating depth 20 thousands shorter than what your bullet jams into lands, for 223 that would put me at 2.290, work up charge till you get low es and don't worry about group till you get that, once you do then go down on seating depth till groups are good and pretty much your done, besides getting at least 2 good and seating accordingly. Well the bullet manufacturer is saying to seat at 2.225 so it will take a lot of shots to get there from 2.290 if it does shoot better at 2.225 so now let's say I have a good powder charge and my bullet shoots best at 2.225, well the pressure is going to increase and is my es still gonna be good like when I started at 2.290 to find that charge. I will also say that I'm getting good groups at 2.225 and I tried making it longer and the groups fell off more the longer I made it, I went to 2.250 and stopped there cause it kept getting worse. Because of the cold and lots of snow here I haven't been using the Chrono so my groups are good at 100 and hopefully my spreads are low, if not, then what, change powder, primer? But my main question is why not seat or at least start where manufacturer recommends and if my final seating is very far from where I worked up charge will the charge stay the same, I don't think it would.

Do a 10 round ladder at book coal to find max and look for a ES of 20 fps or better across at least .4 gr of powder. At .2 gr increments. So say book max is 40 grs. I'd start at 38.7 and load 1 round of 38.7, 38.9, 39.1, 39.3, 39.5, 39.7, 39.9, 40.1, 40.3 and 40.5. So 10 rds. Say 39.7 grs is 2785 fps. And 39.9 is 2800 fps, 40.1 2802 fps and 40.3 2805 fps. And 40.5 is 2820. ES of 5 across .6 grs(39.9 to 40.3 grs) load the middle (40.1 grs), test jump in .3 thou increments.
You can use Cortina's way to find the lands. Or I just use a properly headspaced cased FL sized round with a clean chamber/bore. A long seated round. Bolt removed push round into chamber lightly with pinky and it hangs, the ojive hangs in the rifling, remove and shorten by 2 thou, repeat till you feel shoulder bump the chamber and bullet doesn't hang in the lands/rifling. Back up 5 thou and Repeat. Now you know 0 jump. I do this first and depending on the bullet stat at 10 or 60 thou to test ladder. So find lands, ladder test at your best guesstimate of the correct jump, find a low ES node during ladder (and maybe max charge weight safety), to test jump with. Test jump at 3 thou increments, like Cortina says. And I go back and forth as needed between charge weight and jump to get a moa of .5 or less and a ES of 15 fps, or less. Thats my way. Hope it helps. Only other advice I'd add is get the Hornady bullet and headspace comparators and know how to bump the shoulder back 2 thou from fired/correctly set up FL sizing die, and use cbto/bbto for your measurements as cbto is much more consistent then coal. And FL size only period. As Cortina says. And start annealing. Annealezz is what I have and like it. Clean anneal trim size clean load.

 

[6pakzak]

You can do it either way in reality, there is no magic load. There is a big discussion on this over on the Hide. Bryan Litz basically said neck tension doesn't matter, etc etc. to summarize, there are several loads that will just work with all guns, look at the FGMM bullets... they shoot in almost 98% of rifles, from .223 to 338. goes to show that this isn't super magical. do seating depth sure, then find a powder charge that works best for you. often times you shoot a node and go back and shoot it and you will find other nodes or it is not repeatable. Also one big take away was the 200 rounds until they found bad nodes outperformed the good nodes. lot to digest there [/QUOT

Do a 10 round ladder at book coal to find max and look for a ES of 20 fps or better across at least .4 gr of powder. At .2 gr increments. So say book max is 40 grs. I'd start at 38.7 and load 1 round of 38.7, 38.9, 39.1, 39.3, 39.5, 39.7, 39.9, 40.1, 40.3 and 40.5. So 10 rds. Say 39.7 grs is 2785 fps. And 39.9 is 2800 fps, 40.1 2802 fps and 40.3 2805 fps. And 40.5 is 2820. ES of 5 across .6 grs(39.9 to 40.3 grs) load the middle (40.1 grs), test jump in .3 thou increments.
You can use Cortina's way to find the lands. Or I just use a properly headspaced cased FL sized round with a clean chamber/bore. A long seated round. Bolt removed push round into chamber lightly with pinky and it hangs, the ojive hangs in the rifling, remove and shorten by 2 thou, repeat till you feel shoulder bump the chamber and bullet doesn't hang in the lands/rifling. Back up 5 thou and Repeat. Now you know 0 jump. I do this first and depending on the bullet stat at 10 or 60 thou to test ladder. So find lands, ladder test at your best guesstimate of the correct jump, find a low ES node during ladder (and maybe max charge weight safety), to test jump with. Test jump at 3 thou increments, like Cortina says. And I go back and forth as needed between charge weight and jump to get a moa of .5 or less and a ES of 15 fps, or less. Thats my way. Hope it helps. Only other advice I'd add is get the Hornady bullet and headspace comparators and know how to bump the shoulder back 2 thou from fired, and use cbto/bbto for your measurements as cbto is much more consistent then coal. And FL size only period. As Cortina says. And start annealing. Annealezz is what I have and like it.

Sounds good, I'll try that, I bump shoulder and anneal, how do you FL size, with bushing die? I was wondering what Corrina is doing.

 

[6pakzak]

Do a 10 round ladder at book coal to find max and look for a ES of 20 fps or better across at least .4 gr of powder. At .2 gr increments. So say book max is 40 grs. I'd start at 38.7 and load 1 round of 38.7, 38.9, 39.1, 39.3, 39.5, 39.7, 39.9, 40.1, 40.3 and 40.5. So 10 rds. Say 39.7 grs is 2785 fps. And 39.9 is 2800 fps, 40.1 2802 fps and 40.3 2805 fps. And 40.5 is 2820. ES of 5 across .6 grs(39.9 to 40.3 grs) load the middle (40.1 grs), test jump in .3 thou increments.
You can use Cortina's way to find the lands. Or I just use a properly headspaced cased FL sized round with a clean chamber/bore. A long seated round. Bolt removed push round into chamber lightly with pinky and it hangs, the ojive hangs in the rifling, remove and shorten by 2 thou, repeat till you feel shoulder bump the chamber and bullet doesn't hang in the lands/rifling. Back up 5 thou and Repeat. Now you know 0 jump. I do this first and depending on the bullet stat at 10 or 60 thou to test ladder. So find lands, ladder test at your best guesstimate of the correct jump, find a low ES node during ladder (and maybe max charge weight safety), to test jump with. Test jump at 3 thou increments, like Cortina says. And I go back and forth as needed between charge weight and jump to get a moa of .5 or less and a ES of 15 fps, or less. Thats my way. Hope it helps. Only other advice I'd add is get the Hornady bullet and headspace comparators and know how to bump the shoulder back 2 thou from fired/correctly set up FL sizing die, and use cbto/bbto for your measurements as cbto is much more consistent then coal. And FL size only period. As Cortina says. And start annealing. Annealezz is what I have and like it. Clean anneal trim size clean load.

How exactly does cortina FL size, what kind of die does he use.

 

[Philward]

I think he just neck sizes...

 

[6pakzak]

Ok quiet texan I know you know, I know he don't neck size only, please save me the trouble of looking through all these videos of his, I'm guessing collet FL die or custom FL die, probably custom?

 

[QuietTexan]

He makes his own dies from sizing reamers ground to his specs. At least that what he shows on his channel, maybe there are others I've missed.

Honed dies are arguably the best if you know the specs to get it honed to. A bushing die is going to be the most flexible to experiment with if you don't know what spec to get.

IMO start with a bushing and move on from there. Don't get wrapped up in concentricity while you're messing with the die, figure out how the neck sizing changes actually impacts what you're shooting, and make decisions then. You'll know when you need to get a honed die, it'll be when you know what spec to get it cut to. Or at least are willing to commit to a spec for what the die will cost.

 

[WildRose]

I agree, but one thing I now question is about Harmonics...
Let's take FGMM loads, .308 or 300WM to keep it simple. They shoot so well out of all sorts of shapes and sizes. Meaning different barrel lengths, barrels, stocks, how the rifle is shot , and it all prints nice little groups.... there's no way harmonically that FGMM ammo or even Prime ammo is tuned to everyone's rifle unless Harmonics aren't as important than we think.
It makes you pause and wonder if Harmonics is not as big of a deal as we think... then you get the barrel tuners involved. Crazy to think about. According to some they say it's too hard to measure

The thinner the barrel the more of a difference it's going to make.

The Ammo Manufacturers obviously have some proprietary secrets they are not letting the rest of us in on because particularly in various 30 cals I've seen a lot of factory ammo that shoots amazingly well that nobody seems to quite be able to duplicate in their handloads.

 

[6pakzak]

How exactly does cortina FL size, what kind of die does he use.

This is the method I used for my 6.5 creedmoor except I went up in .1 increments with powder

 

[QuietTexan]

FGMM is based on work specifically aimed at finding large, forgiving nodes for 300 meter .308 WIN loads to beat the Europeans. It's also slow, something like 2650 on the box when a handloader can push that bullet 250 FPS faster easily. But that pushes it out of the nice fat harmonic node it sits in. Compromises all around.

This is why I say get speed with a bigger case, don't push something faster than it needs to be just to get speed from it and deal with the associated compromises.

 

[6pakzak]

He makes his own dies from sizing reamers ground to his specs. At least that what he shows on his channel, maybe there are others I've missed. Honed dies are arguably the best if you know the specs to get it honed to. A bushing die is going to be the most flexible to experiment with if you don't know what spec to get. IMO start with a bushing and move on from there. Don't get wrapped up in concentricity while you're messing with the die, figure out how the neck sizing changes actually impacts what you're shooting, and make decisions then. You'll know when you need to get a honed die, it'll be when you know what spec to get it cut to. Or at least are willing to commit to a spec for what the die will cost.

He makes his own dies from sizing reamers ground to his specs. At least that what he shows on his channel, maybe there are others I've missed.

Honed dies are arguably the best if you know the specs to get it honed to. A bushing die is going to be the most flexible to experiment with if you don't know what spec to get.

IMO start with a bushing and move on from there. Don't get wrapped up in concentricity while you're messing with the die, figure out how the neck sizing changes actually impacts what you're shooting, and make decisions then. You'll know when you need to get a honed die, it'll be when you know what spec to get it cut to. Or at least are willing to commit to a spec for what the die will cost.

Trust me I don't think concentricity is the end all be all but in my rifles it has been a definite improvement, no crazy fliers anymore, other rifles may not be so sensitive, from what I can gather it seems like neck tension is the biggest factor and I'm sure with what Cortina is using he don't have to worry about runout. That's why I got the mandrels you suggested, to work on neck tension, my 223 shot it's best group using them, AR-15 and bolt. Keeping it straight is just another part of keeping it the same and it really makes me happy when the gauge hardly moves and I like to be happy, lol.

 

[WildRose]

Trust me I don't think concentricity is the end all be all but in my rifles it has been a definite improvement, no crazy fliers anymore, other rifles may not be so sensitive, from what I can gather it seems like neck tension is the biggest factor and I'm sure with what Cortina is using he don't have to worry about runout. That's why I got the mandrels you suggested, to work on neck tension, my 223 shot it's best group using them, AR-15 and bolt. Keeping it straight is just another part of keeping it the same and it really makes me happy when the gauge hardly moves and I like to be happy, lol.

If you're trying to go from a +1 MOA rifle to a sub half MOA rifle, the smallest things can make a really big difference.

Concentricity is certainly one of those small things that can have a big effect.

 

[6pakzak]

If you're trying to go from a +1 MOA rifle to a sub half MOA rifle, the smallest things can make a really big difference.

Concentricity is certainly one of those small things that can have a big effect.

I read tests on this, many, and in most cases it's been an improvement, IDK for sure but I'm thinking probably makes more of a difference if bullet has a longer jump to lands