acceptable over/under for COAL and powder charges?

[davsco]

so i'm new to this.  using a dillon 750 and their 38 super dies, what is an acceptable +/- for overall length of the cartridge?  i adjust the seater die to 1.235 by trial and error with hornady hap 125g and i get a couple +/-.001 or .002 but then i start getting lengths from 1.230 to 1.242.  is that in the range of acceptability or do i have a problem?  i will say i hate their dies with the clips on top, what a pita vs others where you tighten down the die and then screw in the seating stem as needed.

 

related, what is an acceptable powder measure (again the dillon 750 one) drop variation?  i know powder shape/profile comes into play.  so how about 3n38 which seems pretty fine-grained?

 

thanks!

[GringoBandito]

I would be fine with that OAL variation as long as my rounds passed the plunk test at 1.240. If I new the max OAL was 1.230 and I had rounds load to 1.240, I would shorten my OAL to 1.220 knowing that my longer rounds (1.230)  woudn't have a problem passing the test. 

 

Regarding load weight variation, I load n320 and see the occasional variation of .5 grains. With CFE, It was always spot on without any variation to speak of. 

 

I hope this helps. 

[zzt]

I cannot speak to Dillon dies, but I don't get that much variation with my Hornady dies.  With 115 HAPs I get no variation.  With Montana Golds I get a tiny bit.  With Precision Delta a get more.  A .012" range is too much, so you may be doing something wrong.  I seat and crimp at different stations.

 

I load 3N38 and get no variation that I can measure.  My scale is only accurate to .1gr, so there may some variation less than that.  Also I use a Hornady powder measure which is considerably more accurate than the Dillon.  I hated the Dillon powder measure.

[Farmer]

I like to keep things within .003

[davsco]

well i ordered another seating die, redding competition, we'll see if that fixes things, at least it will make it a lot easier.  maybe there's some runout in the dillon shellplate?

[4n2t0]

1) Which end of the seating stem are you using?

2) All stations must be filled to get consistent seating.

3) I use Dillon dies exclusively. When the shellplate is tightened properly on my 650 I get very little variation in length.

[davsco]

1 hour ago, 4n2t0 said:

1) Which end of the seating stem are you using?

2) All stations must be filled to get consistent seating.

3) I use Dillon dies exclusively. When the shellplate is tightened properly on my 650 I get very little variation in length.

yeah just checked and my shellplate was a little loose.  if i crank it down then it won't cycle.  so i cranked it down and loosened it just a tad.  it doesn't cycle as easy as when loose but it does cycle with a little force and seems to have lost the wobble.

 

i am using the seating stem side that is closest to my bullet profile.

[4n2t0]

Slowly loosen the shellplate until it JUST starts to move with very little/no resistance. Also, I don't load HAP's but you might want to flip the seating stem over to see if it will produce a more consistent overall length off the ogive (if even possible???)

Edited January 30, 2021 by 4n2t0
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[Kokeman]

The instructions from Dillon on my 550 says OAL within .016" is normal. That is ±.008. I am ±.003 with 9mm in my 550.

 

[stick]

Same headstamp on the brass?  I will allow .03 +/- on my XL650 will Lee dies because of mixed brass.  With the same brass, I would expect much better results. 

As for the powder, I don't see many variations on my drops.  Acceptable for me on powder drops would be .01 +/- but the powder I use on my XL650 meters extremely well.

[rooster]

If your seat die is seating off the bullet ogive, then the amount of bullet inside the case is pretty much spot on. 9mm oal variations can be due to a lot of reasons. Measure your bullets your probably going to get at least .005 right there, add in other factors and that’s why 9mm gets around .010 variations in oal.

[Darrell]

I did an experiment the other day with my Precision delta 124 JHP and Redding competition seating die. I notice my OAL changing by +/- .009" measuring of tip. I used my Hornady OAL checker that measures off the ogive and my variation was only .0015 on the same bullets tested earlier. So if I'm measuring off the tip I set one for what I want and let the rest vary and don't worry about it because the ogive from the rifling will be what matters.