ES and seating depth.

[DustThroughaFan]

Some go after seating depth first then go after powder charge and some go after the charge first then go after seating depth. I'm in the latter category.

I started out at .020" jump, 2.920" base to ogive, and I'm working backwards. 300winmag, 215 berger hybrid, federal 215m primer, 79gr of N570 in a Norma case.

This load went 2913 fps (three shot average) and had an es of 12 but grouped about ¾"
Okay, seating depth time.

Pushing in .003" at a time and at .012" deeper I've gained 47 fps and ES is now 39. As I started pushing the Buller back it grouped about the same ¾" then it opened up a little more but it's going back in the right direction now. Hovering a little over ½"
I've got two more groups loaded at 2.905" (-.015") and 2.902" (-.018")

Can I just back off the charge a little to get the es back or should I go ahead and find the seating depth then go over the charge again? Starting to show a little pressure now.

 

[Dmagna]

How many 3 shot groups did you do to establish a 12es?

 

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[.300 Dakota]

The fact that you gained velocity was a sure sign your pressure was increasing, even before you saw other indications. I typically see ES narrow as I go closer to the lands. In your situation, since the ES was fine further off, I'd back the bullet down to about .030" off and increase charge by .3 - .5 grains and see what happens. That increases your load density, which sometimes improves consistency in a load.

 

[MagnumManiac]

You're doing it wrong, tuning seating depth should be done first because it will change the node, as you discovered, far too much trying to tune seating depth after tuning powder.
Doing it your way will repeat, groups will close then open and powder is a course tune, which is why it's doing what it's doing now.
I was once a believer in powder first, then seating depth, but after many attempts at seating depth first with a middle of the road load, the outcome has always been easier to tune powder with a tuned seating depth. Also, you may find .010" off the lands where it all comes together. I have always found .005" increments to work better than any other number, .010" is course, .005" is fine in regard to tuning and .003" is almost negligible.
In the 300WM, which I have 5 hunting rifles, one of which is a 5R and unfired, have all got SAAMI chambers, however, my comp barrels and 1 custom have the A191 chamber, which is far easier to tune across the board.

Cheers.

 

[Longtine88]

With the 215:
I start .003" off lands
Pressure ladder on powder at .003"OL and pick a flat spot. I'm generally 10 shots in now
I pick a charge close to my target velocity
Seating depth going away from lands .003" at a time 3 shot groups at 500.
90% of the time my seating depth will show before I get past 0.025" OL. Worse care I'm 24 shots in.
Then powder charges below 1.5 grains 2 shots at a time going up at 500 yards or more and look for my vertical dispersion. Just by experience I rarely shoot more than 5 combos. 44 shots in now max. Tweak seating and I'm done. 215's are very predictable to me.

 

[Laguna Freak]

I've found nosler, swift, and even cheap bullets group best between .055 to .075 off lands in 3 different rifles. I usually start around .060 to .065 off and do powder charge tests, then fine tune seating depth.

 

[DustThroughaFan]

How many 3 shot groups did you do to establish a 12es?

That was just one group out of five I think, all different charges. That one was the best. Small sample I know. I typically load three and if I come across something that shows promise, I'll load five to verify. This time I skipped that for some reason and went straight to seating depth.

 

[DustThroughaFan]

The fact that you gained velocity was a sure sign your pressure was increasing, even before you saw other indications. I typically see ES narrow as I go closer to the lands. In your situation, since the ES was fine further off, I'd back the bullet down to about .030" off and increase charge by .3 - .5 grains and see what happens. That increases your load density, which sometimes improves consistency in a load.

I'm already at a point with pressure where I think I'm going to have to back off. I don't think I can increase charge at this point.

You're doing it wrong, tuning seating depth should be done first because it will change the node, as you discovered, far too much trying to tune seating depth after tuning powder.
Doing it your way will repeat, groups will close then open and powder is a course tune, which is why it's doing what it's doing now.
I was once a believer in powder first, then seating depth, but after many attempts at seating depth first with a middle of the road load, the outcome has always been easier to tune powder with a tuned seating depth. Also, you may find .010" off the lands where it all comes together. I have always found .005" increments to work better than any other number, .010" is course, .005" is fine in regard to tuning and .003" is almost negligible.
In the 300WM, which I have 5 hunting rifles, one of which is a 5R and unfired, have all got SAAMI chambers, however, my comp barrels and 1 custom have the A191 chamber, which is far easier to tune across the board.

Cheers.

I got the .003" increments from watching too many F class reloading videos. I figured it was negligible also until I tried it in my 308. Made a believer out of me. They say nodes come in .006" increments. .005" I believe would still work fine, any more than that I also believe would be too course.

This rifle was cut with a saami reamer and then throated to run the 215's at max length. Knowing what I know now, I'd have gone another route. The rifle has shot in .3" territory with a 212eldx so I know it will shoot. It's got 297 down the tube right now. It's shot some decent groups with a 215 and magpro but a friend gave me some of this N570 to try so I started over. I actually had decent luck jumping .060" with that powder but like I said, figured I'd start from scratch.

 

[Tiny Tim]

As Magnum pointed out, your finding that seating depth changes are affecting your speeds, possibly pushing you in and out of powder nodes. You end up chasing your tail.

I used to do it this way until other members pointed me toward seating first. With a chronograph you see these different variables interacting with one another. Do the seating depth test first, and do it outside of a good node. You will find a definitive depth. Then powder charges changes will only change velocity.

Last rifle I did this with started at .010 off and saw on average, a reduction of 10 fps for every additional .015 increase in jump.

 

[DustThroughaFan]

I'm going to shoot these last four that I've got loaded and if nothing shows up I'm going to change my ways.

I had asked a question on another forum about a generic good load for a 215 and a guy shared one with me that he said had worked in several of his winmags. That load was close to .100" jump and shot under ½ moa but it was terribly slow. Something like 2700 fps.

I just went back over my targets/notes and the exact load was .114" jump, 76gr of h1000 with a federal 210m which I loaded in Norma cases. Averaged 2748 fps, sd was 3.3, and es was 7. Shot a .365" for three shots. Maybe I should just pour a little more powder in this one and see what happens.

Something else I've noticed. Looking back over my 212eldx targets, there are several loads with slightly different charges, primers and seating depths that I was trying but the ones that are at the same depth I selected for the final load all shot pretty good despite what the es/sd was doing.

 

[Mike6158]

Concerning seating affecting the powder charge. I just tested that earlier in the week. I hadn't intended to but I had the data so I took a look. .20PPC seating depth test with 55gr Berger BT Varmint and N133. It's kind of a mental jump but the Chronoplotter software didn't care that I shot the test longest to shortest. To match the powder charge trend you'll have to mentally flip the seating depth chart. I can flip it in software but text is displayed backwards. Either can be flipped btw.

Note that powder charge is a single value along the X axis. ES / SD / Average velocity are what changed.

And for the people that can read backwards (I can, a little). The seating depth trend flipped to match the powder charge test.

 

[L.Sherm]

Bergers are a completely different animal than nosler and swift bullets.
It is absolutely untrue about seating depth first, I always do a powder node first and seating depth second and have been very successful on probably 75 rifles.
I know some successful BR shooters who do it exactly that way too.

 

[MagnumManiac]

Bergers are a completely different animal than nosler and swift bullets.
It is absolutely untrue about seating depth first, I always do a powder node first and seating depth second and have been very successful on probably 75 rifles.
I know some successful BR shooters who do it exactly that way too.

How can you say it's untrue…it works for me and many others, it simplifies tuning powder, and there are many powder nodes, and there are many seating depth nodes, some overlap and some don't…just like all aspects of handloading.

Cheers.