Seating die/stem for 20 P

[Bachekermooni]

My CZ 527 build is nearing completion (in my hands late next week). So I tested my modified once-fired 223 Hornady cases with 34 dogtown, 32 and 40 V-max to see the runout.

I used my Hornady 223 seater with micrometer and Forster 223 seater with ultra micrometer. Before using them I checked to see if the bullets fit in the stem - they did. There was a better fit (much less, if any, slop with the Forster). So I did the seating. In all cases the runout was the same, 3-4 thou. Meter tip was set just below the metal-plastic junction).
I also spoke to Hornady Tech guys. Their 204 Ruger sleeve and seating stem fit their 223 seater. So I ordered them. Hopefully I can get better runout. Waiting to see the wobble with the .20 stem.

Like to hear about your experience with 20 P seating HW.
Cheers

 

[jepp2]

So I did the seating. In all cases the runout was the same, 3-4 thou

Is that runout or TIR? What is your case neck runout after necking down?

 

[Bachekermooni]

Is that runout or TIR? What is your case neck runout after necking down?

Not sure what TIR is. I did not measure what the case neck runout is. Should I check on the loaded case or unloaded one? Usually the case neck thickness varies by 1-2 thou on Hornady cases. That is why I always use a sizing button. That way I get consistent inside neck diameter and tension.

 

[jepp2]

Not sure what TIR is.

TIR is total indicated runout. It is the total swing of the needle on the indicator. If you needle swings say 0.006" TIR, then you runout is half of that.

The case neck runout will affect the bullet runout.

I always like to size a few cases with the expander removed and measure runout on them. Then size a few cases with the expander in place and measure the runout on those. I've found that if your expander has to open the case neck more than 0.002", it will pull the case neck off center. And that is even using a carbide expander, lubing the inside of the case neck, and setting the expander high so it passes through the case neck just as the neck leaves the neck sizing portion of the die. You have to deprime in a separate step if you do this.

I also like to know the OD of the case neck sized without the expander, and sized with the expander.

You might measure your runout on the bullet closer to the ogive, rather than the bullet tip. You are making the runout more extreme by measure that close to the tip. Just some suggestions.

 

[Bachekermooni]

Thanks Jepp2.
I always decap on a separate operationcreep as well.
Based on your def of TIR, my measurements were TIR.
I make sure to minimize case neck squeeze. It helps with eliminating shoulder creep as well.
I will measure the TIR at closer to ogive.
I agree about case neck measurements with and w/o expander. Unless one turns necks, there is always case neck thickness variations.

Back to original question, any better way to seat 20 P?

 

[GLShooter]

I've used Hornady seating with no issue. I've also swapped some parts in a Redding 223 and done well with it.

Greg

 

[AWS]

I use a 204 Hornady for mine. It works well. I don't chase runout, if it kills coyotes as far as I care too shoot that works for me.

 

[jpx2rk]

I use the Hornady 20 cal seater along with a LEE 223 seater as well. I try different seaters with different bullets as it seems a LEE may/may not seat the 32 or 40g bullet a bit better than the Hornady, so I try anyways.

What powder and load data are you going to try with the 34g DT's??

 

[Bachekermooni]

I use the Hornady 20 cal seater along with a LEE 223 seater as well. I try different seaters with different bullets as it seems a LEE may/may not seat the 32 or 40g bullet a bit better than the Hornady, so I try anyways.

What powder and load data are you going to try with the 34g DT's??

I have AA2230 and TAC. Hodgdon had AA2520 availability a couple weeks ago. I took too long to order. I hear that is the best powder speed and accuracy wise. But I am sure the two I have will work.

 

[TheCZKid]

For seating I use a Redding Competition Series in 204 Ruger, with micrometer top. I purchased a used AR upper and that came with the dies they got, but it's worked well. TIR is between .002 and .004, and that's dependent on how much runout my case has after I size them down. I think my runout is getting less with two things: after shooting the case in my chamber compared to newly transformed brass, and second is turning the necks to uniform the thickness. I talked to Redding as my TIR on the bushing die was up to .005, which is actually .0025 runout, and they said that was actually really good! They said it "sounds like a lot, but .005 runout is actually very small."
I'm currently turning the necks to .013 thickness, seems to make them uniform over the whole neck surface, and not overly thin. I'm sizing the brass with Redding 223 S series die, with 224 neck bushing. It gives enough neck tension for use in my AR, but in a bolt rifle like you have you might be able to use a 225.
Powder I've had good results with VV N133 on 32 Vmax, and on 40 Vmax 8208XBR is good. I don't know on a 34 grain, but I've been told that LT-32 works well on 32 and 40, but I haven't been able to get any to try.