Inconsistent powder drops with Dillon 550B

[razorsharptokill]

I still consider myself fairly new to reloading but have loaded around 700 rounds of various ammo on this press and more than that on an old Lee pro 1000. I am working on a .308 Win. load and using TAC. While setting the powder measure I noticed that the amounts seemed to be off on each drop. I weighed ten drops and had a .5 grain difference from lightest to heaviest and only two repeated weights in the ten drops. I think the cause may be that I only had the powder filled up to t he bottom of the tube. Thoughts? Half full is recommended I see but a half of a grain off at times?

 

[Laelkhunter]

Never had really good luck using the extruded powder through any powder measure. I have the Ohaus Duo Measure, and also a Dillon RL550B. I got to the point where I use Winchester 748 ball powder for my .308, and BL C2 or WW 748 powder for my .223 For blasting ammo, shooting out of a rack grade battle rifle, you probably won't see to much change in anything if the load varies .5 grain. For precision shooting or hunting ammo, I weigh each powder charge on my scale to ensure accuracy.

Also I replied to your request for the RL550 tool head, check that thread for my reply.

 

[BFR]

This comes up a lot on the Dillon forums, the most common solution is to take the powder assembly apart and clean the throat of the aluminum part. I guess they get an oily residue from the powder. Another is to polish the throat and funnel to a mirror finish so the powder flows easier. Stick powders tend to bridge so polishing should help stop that. The wildest trick was some guy rubber banded a battery toothbrush to the bottle, claims the vibration helped the powder to flow consistently. I’ve never been bothered by an inconsistent drop because my OCD makes me weigh every charge anyway unless I’m running low or mid range charged target rounds.

 

[dla]

I still consider myself fairly new to reloading but have loaded around 700 rounds of various ammo on this press and more than that on an old Lee pro 1000. I am working on a .308 Win. load and using TAC. While setting the powder measure I noticed that the amounts seemed to be off on each drop. I weighed ten drops and had a .5 grain difference from lightest to heaviest and only two repeated weights in the ten drops. I think the cause may be that I only had the powder filled up to t he bottom of the tube. Thoughts? Half full is recommended I see but a half of a grain off at times?

I'm just guessing here, but TAC is one of the nicest metering powders on the planet, so I would look at two basic things with your setup.
(1) Is your press steady?
(2) Does the Dillon dispenser return to closed or not?
What I'm imagining is that vibration is settling the powder while the charge slide is in the open position. This happens a lot to folks who forget and run their bench mounted dispenser backwards, i.e. throw open->dump->open, instead of dump->open->dump.

One other thing, on my SDB,(which I believe uses the same style powder dispenser), when I switch powders I usually have to throw at least 20 charges before it settles down. It could be as a previous poster noted that there is some sort of coating taking place. And of course I should mention that if you are reloading in a cold garage you going to see more variation.

Like I said, just guessing.

 

[AKDoc]

I have a Dillon 550b...primarily for high volume 45ACP and 10mm handgun reloading for the past ten years or so and some 223 (these are all modest charges for range practice). I've not had any problems with the powder throws, but I only use ball/spherical powders with it, which I think is what Dillon has recommended (but I could be remembering that incorrectly)....e.g., Accurate 5, 7 & 9, W748, etc.

With extruded powders I use my single-stage press. I'm one of those compulsive guys who weighs every throw and trickles to get it just right, which I enjoy doing with rifle loads and high power pistol (44mag and 454 Casull)...but for high volume reloading like mentioned above I sure prefer the Dillon.

 

[hereinaz]

If you want long range capable loads, vast majority use a scale and dump, even on the progressive.