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Old April 7, 2012, 08:49 PM   #1
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powder bridging

What exactly is "powder bridging"? What about this problem in the Dillon 550B?Any truth to this?
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Old April 8, 2012, 08:52 AM   #2
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Powder Bridging- A Rare Occurrence

When dropping any powder from the measure, bridging may happen. The speed that the measure is operated at has an effect. Fast dropping of the powder may bridge at times. Slower moverment of the measure handle will have more of a trickle affect, no bridging. Some measures have a Handgun Metering Drum for loading small amounts of powder. The optional drum will give less weight variations & slower drop. A drop tube for 22 caliber can restrict the powder drop more then the larger caliber one. Lube remaining in the case neck (223 Rem) can slow powder drop if the expander has not removed the wet lube. Undersize brass neck wall thickness will not let the expander drag the excess lube out of the mouth. Do not lube with a Qtip, use a nylon brush or a dry lube. Powders that have bridged for me are 800X & Blue Dot when loading 45 acp. Other Example > When it happens, the first case gets less then the required amount, but enough to work the action of a 40 S&W. The next case gets the normal powder change, plus the remaining bridged powder. The maximun load of 11.2 gr of Blue Dot goes into the case, plus the bridged amount of 3.5 gr. When fired, KABOOM. Always look into the case to check powder levels before seating a bullet. Not easy to do using a progressive press. A single stage press, use loading blocks. Very easy to check the powder levels this way. [IMG][/IMG]

Last edited by 243winxb; April 8, 2012 at 09:17 AM. Reason: add title
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Old April 8, 2012, 03:55 PM   #3
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Station 4 on my dillon 650, I can see in my case, always look plus I have powder check. I am afraid of just that, kaboom! Also frequent scale checks
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Old April 9, 2012, 08:31 AM   #4
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I think it was Uncle Nick who posted something you could print out and cut different size baffles to help prevent this. I think I used a piece of plastic from a one gallon bleach container.

I have not had the problem yet, but I did put a baffle inside my RCBS Uniflo-powder measure.
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Old April 9, 2012, 10:51 AM   #5
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I had AA2520 "bridge" in my Dillion 550B powder funnel.

AA2520 is a ball powder. I would never have believed ball powder could clump in a measure, but it did.

Accurate Arms buys their powder from a different vendor so the physical characteristics of each lot can be very different. I believe the particular lot of AA2520 that gave me troubles was from Czechoslovakia. This lot had a lot of dust and that dust coated the interior of the powder funnel and clogged up my .223 powder funnel. I had to weigh and disassemble a number of .223 rounds. I had some light charges followed by a powder dump when the funnel cleared.

I loaded some more .223 ammunition, sticking a Q-tip up the funnel on a regular schedule, to keep the dust level down in the funnel.

You can expect long stick powders to bridge, the smaller the caliber the more likely you are to get powder bridging.

Incidentally, I have several kegs of Chinese made AA2520. That powder is particularly clean, dust free, and throws well.
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Old April 9, 2012, 02:01 PM   #6
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I've never heard of powder bridging being a problem on any of the Dillon loaders...all of their powder measures have baffles in them...and they're there to prevent any clumping...or bridging.....

I have buddies that use Dillons SDB's, a few with 550's, some with 650's and one with a 1050 .../ and others using RCBS, PW, Hornaday ...and nobody has ever mentioned any kind of a powder bridging...issue / on any kind of a handgun powder....but 90% of my buddies that are reloading for handgun calibers from 9mm to .44mag ...are using one of the Hodgdon powders...Universal, TiteGroup...and a couple use Clays...

Personally, I've loaded tens of thousands of handgun rounds on Dillon 650 ...with no powder bridging issues...and I don't think the powder measures on the 550 and the 650 are significantly different / maybe identical ...but you can call Dillon and ask them.

Static electricity / is a big deal ...and can affect the way a powder drops in any powder measure....but powder bridging, I don't believe its even a remote issue. I realize one response said he had it happen ...and I'm not saying he's lying.../ but I am saying I cannot imagine it happening ...and I'm wondering if there were other things that contributed to it ...( humidity, something loose on the powder measure, not fully cycling the handle on the press, the dust he was finding ( which is very odd ), why there is a variation between batches of that powder, etc......) ...but if the powder he was using had a lot of dust ...I can see that dust jamming any powder measure / not just a dillon system.../ but to me - a dusty powder a powder quality control issue ...not a press issue.
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