Why doesn't my Dillon 550B meter consistant weights?

[teddy12b]

Hello,
I'm hoping I'm not the only guy on this forum who uses a Dillon 550B and it's likely this has already been discussed, but I would like to hear some ideas.
I have a Dillon 550B that works great for handgun cartridges because the powder measure meters consistent weights and I can really crank out the ammo.
When reloading for rifles I've always taken the brass out at the second stage and manually filled it with powder using an RCBS chargemaster combo and then I'd put the brass back into the Dillon knowing the exact powder weight every time. That works great, but it does take more time and I'd like to start using powder dispenser to speed things up for rifles.
I'm primarily concerned with reloading for 223 and I've tried using powders such as H335, H322, H4198, Varget, and none of them meter consistently. It's like every so often there is a weird charge that is .2 - .6 grains off. I use the same technique while working the press and I can't figure it out. I bought my Dillon 550B brand new about 2 or 3 years ago.

 

[7mmSendaro]

My 550B is very consistent loading .223 with Varget. I am always within .1 when I check charges.

 

[overbore]

I have the same problem with 4895 in .308's and do not have an easy answer beyond looking at each case after charging. Overbore

 

[BHP9]

I have the same problem with 4895 in .308's and do not have an easy answer beyond looking at each case after charging. Overbore

It's fine with the ball type powders but you will have problems with stick type powders.

The Short Cut powders should be OK too.

 

[overbore]

I suspect the problem may be mitigated by allowing the dispensing arm's curved arm to hit the stop thereby shaking the powder slightly. I have gone so far as to change out the entire powder unit with all new components. Overbore

 

[anachronism]

Here's what I do. After setting up the powder measure for case length, I fill it with my intended powder, them tap the side of the reservoir sevral time with a plastic screwdriver handle before setting my charge weight. I used to have a lot of trouble with inconsistent charge weights until I realized that my powder charge was getting heavier as I loaded. Since the whole powder measure moves on the 550, I feel that the constant cycling was causing the powder to settle in the reservoir, essentially making the powder charge more dense with each cycle. The type of powder used has a big effect on this too, dense, fine-grained powders like TAC meter more consistently for me than say, IMR4895.

 

[Winchester 69]

You may try adapting a Hornady powder measure with their case-activated load system, or simply using the funnel loader with an off-system powder measure. Price to be paid with stick powders.

 

[overbore]

Have been able to improve powder weight accuracy by adding grounding wire and adding more Knock to the charge bar arm. Many thanks, Overbore