Yikes, my uniflow free flows

[popper]

Loading some 308 today with H4895 and uniflow started dumping powder when the handle is up or down. I took it apart and didn't find anything broken. Did find a small ring of powder gunk when I undid the nuts, I assume this just collected at the bottom of the cylinder. Like 38 gr up and 50 gr handle down. Anyone have this experience and know what causes it? Every once in a while it crunches when it cuts a grain but not this. Had been using HP-38 and then switched and dumped 5 or 6 weigh loads, noticed it when I seated a CB and a pile of powder fell out on the bench. Yes, I will pull them all.

[dragonrider]

I believe what is happening is called bridging, the powder is actually forming a bridge and not all of it is falling out at once. It is likely that some of your rounds will be over charged and some will be undercharged, but then again that could have been the first event but you can't count on that. You are correct to pull them all and check.

[popper]

The weird part is it continued until I had emptied all the powder from the container, about 25 rnds worth. Like dots and dashes dumping into the powder jug. Found 2 sticks of powder stuck to the inside of the drop tube.

[geargnasher]

Popper, you're describing the impossible here as far as I can tell. The only way powder can flow from the hopper out the drop tube is if the rotating drum has shifted to the side a LOT, the housing has cracked, there's a major groove in the drum, or the adjusting rod is out of it. The adusting rod would have to be out of it for significant lateral drum movement anyway. You have me baffled for sure.

Gear

[bootsnthejeep]

Yeah, I just had my uniflow all apart to put it back in service after RCBS sent me a new hopper. I can't figure how that's possible either. Weird.

Take it apart again and take some pictures in progress. Probably something simple.

[popper]

The only thing I can figure is that HP-38 and fine powders can glob and possibly cause a blockage. At the end the HP-38 loading I noticed the handle was kind of 'locking up' and I always dump all powder from it when finished. The blockage had to be below the rotor but I didn't find anything but 2 grains of H4895 which is a really short stick powder. I cleaned it well when I disassembled it and only got a grimy finger and rag. I mount it on my ss press and only noticed when the press clunked and powder dropped all over the WB. Yes I do look into the case for proper powder drop. Probably wouldn't have posted if I'd found the culprit for sure, I don't think there is such a thing as a powder fairy. Just another thing to watch for in the future.

[deltaenterprizes]

Static electricity ?

[3006guns]

I ran into a similar problem with my Uniflow but I'm not sure if it fits your description or not. My particular measure has been in my possession since 1972 and with care/cleaning has always given good service......until I tried Trail Boss for the first time.

I'd get a normal charge, then two light ones and finally a terrific overcharge. I immediately blamed the powder's light "fluffyness" as the culprit and started using Lee dippers. Sometime later I found the real cause.....I had the small aluminum drop tube installed and it had been in there for years. Although it worked fine with all of my other powders, the TB would bridge, drop a small amount, then pick up more from the reservoir when cycled and dump the whole mess at once. Like you, I pulled any finished round apart.

I changed to the large drop tube and it started dispensing accurately.

[Dale53]

I did a good bit of Schuetzen shooting in the recent past. One of the popular powders for 32/40 is 4759. It is quite coarse grained. I was using a Redding micrometer powder measure. Never had a single problem with any other powder. It started bridging with 4759. I talked to an "old hand" and he suggested that I take a rat tail file and make the plastic drop tube oval inside. I did this, and it never bridged again.

Not long after I decided to use finer grained powders that measured well. They also work well with any of my several powder measures.

Another thing to look out for. Spiders will occasionally build webs in orifices. I have found them in weird places including gas pilot lights. They can cause no end of problems.

When I have a problem such as this I dismantle everything completely and examine it closely. Oft times the problem becomes obvious....

FWIW
Dale53

[dmize]

From past experience I would be willing to bet its getting hung up in the small drop tube spout. When I load my 22-250 and 243 I watch the powder fall thru the tube and you can see when it doesnt all drop,I usually lift the handle up a little and bounce it off the body at bottom of stroke.

[popper]

I wondered about spiders and such, didn't find anything. I'll check that jug of powder when I open it again. Loaded another 1/2# hp-38 with no problems. I bang the handle up and down always.

[lwknight]

Try a test run thumping the drop tube after each dump.
I bet on a log jam in the tube.

[popper]

I had ben loading with HP-38 and LeverR which are both fine coated powders. When I first disassembled I found a glob of powder residue, hard, shaped like a 'C' clip in the cylinder. I think part of that dropped and stuck above the drop tube (plastic tube was clean - I checked it first), making a ledge to hold back some powder(a lot). I loaded 12 rnds before I stopped, weighed them and 1 was high, 1 was low and the rest were fine and shot OK. My conclusion is when the handle gets 'stickey' to move, it needs cleaning. Never did find that 'chunk' but loaded from the same powder can OK - I'll keep looking for it.

[BK7saum]

I get bridging routinely with stick powders. The fix for me is to slowly dump the powder from the rotor into the drop tube so that it flows into the case without bridging.

[canyon-ghost]

My powder measure stand has marks on the front from me tapping on it with the edge of a spoon. Some powders like to bridge and some are great. SR 4759 is one of those I love but, always wants to bridge. Then, 2400 never seems to bridge. The difference in granule size and shape has a lot to do with it. I like my Redding #3, it's a decent measure.