Variable weight throws on 550B

[Youngeyes]

I load 38spl,44 mag and 45acp on the dillon 550B. I've noticed more variation on throw weights in the 4gr throws vs the 10-12 gr throws. I use similar powder, 700X and unique. The other difference is that I use the large powder bar for the 10-12 and the small bar for the 4 gr throws. Is it just the low weight of powder or do the powder bars make a difference? The unique on the 44 is the most consistent. I appreciate your thoughts on this.

[LPatterson]

You didn't mention the degree of variation or the method you used to determine that variation. Is it weighing each charge individually vs average weighing? First there must be a case in every station. Second I hope the 10-12gr charge is only in the 44 Mag. Third the powder bar may indeed be causing the variation because volume becomes weight and there are different size openings and depths to deliver the volume.

[atbarr]

First there must be a case in every station.

Why?

Thanks,

A.T.

[Alan550]

The shell plate has to have "some" play in it in order for you to rotate it. Consequently, all stations must have a case in them to get a consistent movement on the powder measure. Otherwise, the shell plate will tilt ever so slightly. Same thing applies for setting each station on there. If you set the bullet-seat die with the other stations unoccupied, the seating depth will change when all stations are full. Same with the powder measure. You may not get the full stroke of the bar without the other stations full, and if you set it with them empty, then you'll probably end up with more case-mouth expansion than you want once you get running.

Alan~^~

[Youngeyes]

You didn't mention the degree of variation or the method you used to determine that variation. Is it weighing each charge individually vs average weighing? First there must be a case in every station. Second I hope the 10-12gr charge is only in the 44 Mag. Third the powder bar may indeed be causing the variation because volume becomes weight and there are different size openings and depths to deliver the volume.

I use both a digital ( the one BE sells) and a beam. All station full. To check, I was looking at every other rd. I use 3.4gr 700x with a 158 XTP jhp bullet on the 38 spl, 4 gr 700X with a 230 FMJ for 45acp, and 10gr unique with a 240 gr xtp jhp with the 44 mag. I get 3.2-3.6gr on the 38, 3.8-4.2 on the 45, but only9.9-10.1 on the 44 mag. Usually I'm pretty dead on at 10 gr. I only use the large bar on the 44 mag. Do you think if I try a powder requiring a larger throw it might settle down? I don't usually load very hot stuff, so I don't normally us a lot of powder. Do you load heavier and get a more consistent throw? Thanks LeRoy,and thanks for your service.

[atbarr]

if you set it with them empty, then you'll probably end up with more case-mouth expansion than you want once you get running.Alan~^~

That answers a lot.

Thanks for taking the time to answer this.

A.T.

[bdpaz]

So you are +/- 0.2 grains with 700x in the small bar and +/- 0.1 grains with Unique in the large bar. I'd try testing (as in using fired cases without removing the old primers so you can't accidentally load functioning rounds!) Unique at 4.0 gr in the small bar and 700X at 10.0gr in the large bar. See if the variation follows the powder, charge bar, or amount.

Edited January 5, 2010 by bdpaz

[benos]

Also, I copied this from my Which Dillon:

Here's a technique that works well if the cartridge case will hold two charges of your target powder charge. Clear all the empty cases out of the Shellplate, and remove the Locator Buttons from the powder dropping station and the bullet seating stations. Put an empty, primed case in the powder dropping station. Cycle the handle so it drops one charge in the case. Remove the case, place it back in the powder dropping station and cycle the handle again. Remove the case and dump the (two charges of) powder in the scale's pan. Repeat that procedure. Now you have four charges in the pan. Say your target powder charge is 4.0 grains; your scale should read 16.0 grains. You might make a sticky for your reloading bench that has 4x totals for your favorite charge weights. Example:

4.6 = 18.4

5.2 = 20.8

Calibrating the Powder Measure using this technique is not only considerably more accurate than the "drop-one-charge-then-adjust-the-Powder-Measure" method, it will save you quite a bit of time, in the long run, as well.

Then just forget about individual charge weights.

be

[Youngeyes]

So you are +/- 0.2 grains with 700x in the small bar and +/- 0.1 grains with Unique in the large bar. I'd try testing (as in using fired cases without removing the old primers so you can't accidentally load functioning rounds!) Unique at 4.0 gr in the small bar and 700X at 10.0gr in the large bar. See if the variation follows the powder, charge bar, or amount.

Simple. Easy. Safe. Methodical. Always the best. Good advice.

[Youngeyes]

Also, I copied this from my Which Dillon:

Here's a technique that works well if the cartridge case will hold two charges of your target powder charge. Clear all the empty cases out of the Shellplate, and remove the Locator Buttons from the powder dropping station and the bullet seating stations. Put an empty, primed case in the powder dropping station. Cycle the handle so it drops one charge in the case. Remove the case, place it back in the powder dropping station and cycle the handle again. Remove the case and dump the (two charges of) powder in the scale's pan. Repeat that procedure. Now you have four charges in the pan. Say your target powder charge is 4.0 grains; your scale should read 16.0 grains. You might make a sticky for your reloading bench that has 4x totals for your favorite charge weights. Example:

4.6 = 18.4

5.2 = 20.8

Calibrating the Powder Measure using this technique is not only considerably more accurate than the "drop-one-charge-then-adjust-the-Powder-Measure" method, it will save you quite a bit of time, in the long run, as well.

Then just forget about individual charge weights.

be

That works on average, but I'm not changing settings in between throws, only weighing them. If it keeps up this way I'll be shooting one rd at 3.2 gr and one at 3.6. The heavier weight is more stable, or seems to be. I'm still well below max but can actually feel a difference when shooting some shots vs others from the same batch. I actually use your technique. Read it when I first started reloading. Started checking more closely when I got experienced enough to feel the difference in my loads.

[benos]

That works on average, but I'm not changing settings in between throws, only weighing them. If it keeps up this way I'll be shooting one rd at 3.2 gr and one at 3.6. The heavier weight is more stable, or seems to be. I'm still well below max but can actually feel a difference when shooting some shots vs others from the same batch. I actually use your technique. Read it when I first started reloading. Started checking more closely when I got experienced enough to feel the difference in my loads.

Okay cool.

One thing - you mentioned Unique Powder. I've never used Unique in a Dillon Powder Measure, but I thought I remember more than one person saying it didn't meter well in a Dillon Measure, in the "what powders / Dillon Powder Measures" thread.

Gotta run for now... I'll look for more details later.

be

[Brian1911]

What I have noticed is that if you cycle the press with out brass in the powder station after a few times I think the powder gets condensed and I get heavier throws. In other words when you are setting your powder drop cycle the handle up and down but be sure every time there is brass in that station. If you were setting things like crimp and cycling the handle up and down then went back to check your powder drop it would meter heavier.

[SCV]

I have had the same thing happening with Clays....... Untill I saw my stations were not full.

Edited January 7, 2010 by SCV

[LPatterson]

This may have absolutely no bearing on your problem but when I checked my 9mm&40S&W toolhead powder measure I discovered I am using an X-small powder bar while the powder measure for the 44 mag - 223 is the large bar, the Arrendondo bar in the 45 powder measure has the same x-small type cavity. I remember seeing a post about the amount of powder dropped by each bar but the search foo is frozen this morning. I can say that x-small bar will throw +/- .1 3.8 gr loads of Clays consistantly.

[Youngeyes]

This may have absolutely no bearing on your problem but when I checked my 9mm&40S&W toolhead powder measure I discovered I am using an X-small powder bar while the powder measure for the 44 mag - 223 is the large bar, the Arrendondo bar in the 45 powder measure has the same x-small type cavity. I remember seeing a post about the amount of powder dropped by each bar but the search foo is frozen this morning. I can say that x-small bar will throw +/- .1 3.8 gr loads of Clays consistantly.

I looked at those posts on the search(good idea by the way). It's looking like my problems are powder related. I'm going to try several other powders along with the unique and 700x. I also just bought a chronograph. It should be interesting to see how much speed variation is connected to the powder throw variations. Could be I'm just OCDing for very little reason. I've noticed that the more I reload, the more I get into the tinniest details. I'll post any meanigfull results.Thanks again.