Powder Measure Bridging

[joeb33050]

Sometimes powder doesn't come out of the measure on one operation, but lots of powder comes out on the next operation. The series of events varies, Ex none-lots, or none- none-lots, or none-little-none-lots.
I've seen this with SR4759 for years, never recorded what happened until recently. I have reports on bridging with surplus 4831, Red Dot?, and 700X.
I would like additional experiences including exactly what happened with what powder and measure.
Thanks;
joe b.

[Wayne Smith]

It happens in my RCBS measure with 4831sc (!) and (of course) with 4064 and 4831. That's why I weigh each charge of those powders and put them in the case with a funnel rather than through the measure.

[eka]

I'm like Wayne, I set my RCBS Uniflow to throw the charge close and then trickle up with my digital scale. I can tell if it doesn't drop the whole charge, so I tap it a little to get the remaining powder to fall. Slow, but I'm not going for any reloading speed records.

Take care,

[felix]

Since 1974 I have been rough on my one and only measure, and it still works as advertised. It is the RCBS Uniflow using the pistol size cavity. I have never used the rifle sized cavity, using two throws with the pistol size cavity instead. I slam it down backwards to gather the powder, and slam it down foward to dump. I wait for a half second or thereabouts to initiate a throw into either direction. Bridging is almost non-existant when using such a sharp blow in both directions. ... felix

[Char-Gar]

I bought a used Hollywood measure in 1959 and still use it today. I have used it with just about any kind of powder you can think of. I do like Felix and make certain I bump the handled of the measure both ways with a uniform feel.

From time to time, with long stick powder I get a hesitation in the throw. I just pitch the charge back in the hopper and do it again until I get a nice smooth throw.

I have never hand any of the problems with not all of the powder coming out as mentoned above.

Ten years ago, I was gifted with a Redding measure and I put in a pistol chamber. Charges of less than ten grain of pistol powder are throw with that measure. All of the rest are done by the Hollywood. It is not needed, but I use it in memory of the friend who had it. His widow gave me all of his reloading equipment.

I have had the hollywood 47 years and it was at least ten years old when I got it. It show no signs of wear or loosing accuracy or repeatability. It was the most costly measure on the market when I bought it. It does pay to buy quality equipment.

[Trailblazer]

I use the same technique as Felix does-seems to work.

[StarMetal]

One more reason I and Carpetman use the Belding & Mull, not bridging...and either that powder is full or not before it's transferred to the case. No double charges with the B&M.

Joe

[fourarmed]

Responded to the SEE thread before I read this one. I use the Redding measure most of the time. It will bridge occasionally with any of the bad actors mentioned, though I've never noticed it with the flake powders. With powders that I know are prone to bridging, I double-tap the handle at top and bottom. The double-tap at the dump end just about eliminates the problem. I still look, though.

Incidentally, double tapping at the fill end of the stroke gives noticeably more uniform charges with the flake shotgun powders. It does require a different micrometer setting than when single-tapping

[Harry O]

I would like additional experiences including exactly what happened with what powder and measure.
Thanks;
joe b.

I have two powder measures, an old, old RCBS and a newer Lee micrometer one. The behavior is about the same.

I have found three types of powder behavior. The "chunk" type powder (such as any of the IMR rifle powders) will not feed reliably thorough either one. My solution is to set it to less than what I want and trickle in the rest. Since I am using it to load large rifle cartridges, that does not slow me down much. I also have a couple of sets of Lee scoops and they are more reliable than the powder measures with chunk-type powder.

The next type of powder is "flake" type (like Red Dot or Unique). Sometimes it works and sometimes it doesn't. I have found that humidity makes a big difference with these types of powder. In the winter the humidity is very low and they meter reliably for me. In the summer when the humidity averages 80-90%, it does not meter very well at all. I do the same as above then. Since I am doing this with handgun cartridges (a larger quantity), it does slow me down when I have to trickle. The Lee scoops are about equally reliable as the powder measure with these powders.

The third type of powder is "ball" type (like 2400 or WW231 -- a flattened ball). That works well in the powder measures regardless of the time of year. The powder measures are more reliable than Lee scoops with them.

When I try a new powder, I run a simple test. I pour out a bunch and then put an ordinary handloading funnel on top of the container it came in. Then I pour the funnel full. If it drains out without touching the funnel, it will work in the powder measures. If it occasionally stops and I have to tap it, it will probably not be reliable enough for me through a powder measure. If I have to continually tap it, I have to use the trickler for sure.

I don't believe that any powder measure is reliable enough for progressive loading with some powders. I don't progressive load, but would only do it with ball-type powders.

[NVcurmudgeon]

I've been using the same RCBS Uniflow measure, with rifle chamber, for 35 years or so. I give it two vigorous taps at each end of the cycle and never have trouble with bridging, not even with IMR 4064 and IMR 4350. I load almost everything using loading blocks and the flashlight. I also load some pistol ammo using the Hornady pistol measure, again with loading blocks and flashlight. The two high-volume ammunition productions around here are .45 ACP and .44 Magnum. Both of these are loaded on my Dillon Square Deal using WW 231 and Green Dot powders. This is the only loading where I have to trust the equipment, but both of these powders meter well.

[versifier]

This is a repeat of my post on the SEE thread. It's relevant here, too and will save you the trouble of going back. My technique is very similar to Curmudgeon's, but I use the smaller chamber in it. I don't use progressive presses (nothing against them, though).

As to powder bridging with extruded propellants, I have a simple technique that I use with my Uniflow, and it will work with any steel drum type measure. I tap hard twice on the filling stroke, then tap hard three times on the dispensing stroke. It yields measurably more consistant charges, and it minimizes the bridging phenomenon. You can see its effectiveness through the transparent plastic of the drop tube, and the measure does bridge with only one and sometimes with only two taps when measuring IMR powders. It has become a learned reflex after years of doing it, and I do it automatically even with Alliant and othe easy to meter powders.
I use loading blocks and visually check each case every time, and I can honestly say that in more than thirty years and god alone knows how many thousands and thousands of rounds, I have never had powder bridging cause a partially/overcharged case. I have, when interrupted during the case charging operation, both missed a case and restarted on the wrong one and double charged, but visual inspection with a bright lamp has always caught the empties, and the overflow has clued me in to the doubles. I am very paranoid when using pistol powders in handgun and rifle cases in charge weights that fill less than half the case volume, and I usually check them twice with the bright lamp. I am a creature of habit, and I rely on my habitual routines help to keep me safe.

[Wayne Smith]

Gentlemen

When using 4831sc, 4831, and 4064 in my rifle sized cavity in my RCBS Uniflow - over 20 years old - I am getting as much as a half a grain variation in my thrown charges before trickling. Granted, it's usually much closer than this, but the few low or high ones do confirm to me that I need to weigh and trickle these powders. I'll probably get some 4350 to try in my 7x57, so I imagine I'll see how consistent that one throws, too.

Intrestingly enough, FFG and FG flows fine through my Lyman 55.

[Blacktail 8541]

Since 1974 I have been rough on my one and only measure, and it still works as advertised. It is the RCBS Uniflow using the pistol size cavity. I have never used the rifle sized cavity, using two throws with the pistol size cavity instead. I slam it down backwards to gather the powder, and slam it down foward to dump. I wait for a half second or thereabouts to initiate a throw into either direction. Bridging is almost non-existant when using such a sharp blow in both directions. ... felix

I use the same method and rarely have a problem with powder bridgeing.

[Woolybooger]

Another double tapper here. Two on the up stroke and two on the down stroke. It's an old uniflow also.

[Urny]

I have been experimenting with the Johnson Design Specialties Quickmeasure, learning as I go. So far two powders give signs of bridging, Trail Boss and 4831, but that may be more a problem with technique than the measure itself. No such problems with the Lyman 55 or Accumeasure, or the old Redding side drum measure. I quit using the thimble measures, an RCBS, Lee, and a newer Redding because of the bridging problem. Only the JDS and Accumeasure were purchased new.

[Blackwater]

CAn't remember whether it was Warren Page or Jack O'Connor who was the first I read to recommend it when metering coarse grained powders, but I also use one, two or three "knocks", always using the same number of knocks on both the up and down throws of the handle, since that sets up a better rhythm. Besides, if they're coarse going out the nozzle, they're just as coarse in the hopper, and probably need the same number of knocks on both up and down strokes to be sure everything's settled and consistent.

One other thing:

I early on decided that using the .22 cal drop nozzle on the powder measure would allow me to never have to change it. Once when having trouble dropping 4064, I believe it was, in an '06, I thought going back to the larger .30 cal drop nozzle might prevent the bridging. Danged if it didn't, too! [smilie=p:

Try using the largest caliber nozzle that will fit your case necks. This also helps reduce or eliminate bridging, and the knocks (the coarser the powder, the more knocks) also help eliminate bridging and keep the powder charges more consistent in wt. as well. Over the years, I accumulated some extras, and used drills to make dedicated nozzles for .27, .35 and .45. I know of NO powder that'll bridge with a .45 cal nozzle. Maybe cannon powder? But then the grains would be big enough to handle with fingers, and count individually right out of the bag, so ..... ;-)

[StanDahl]

This may or may not relate, but if you're experiencing bridging in powder-through dies, you can file the drop tube into an oval shape and any powder problems there will disappear. Stan

[lovedogs]

That Versifier and I must be related. We do a lot alike. I use the RCBS Uniflow, and do taps. With any extruded powder I set my measure low, weigh each charge, then trickle to finish. With some flake types that is needed, also. But with ball or spherical it's never been needed.

[Lead pot]

A little tip:

I mounted a small sewing machine motor with a small counter weight on the shaft on the shelf that holds my powder drop, the vibration settles the powder for a uniform drop and the bridging is none existing.
When the lever is in the up position just let the powder settle for a few seconds and the drop is consistent even with 1F.

Kurt

[versifier]

Kurt,
Never fail to praise a brilliant idea, and the motor with the offset weight is a stroke of genius. It reminded me of the shaker motors that are put on concrete forms to settle the mix and eliminate voids. It occurs to me that there are other kinds of small vibration-inducing doohickies (yes, I know, but I'm being serious and I'm not going there :razz: ) that could be easily made to work in similar situations, especially with powder measures like Lee's that aren't made of heavy steel.

Dogs, do you keep springers, setters, or Rotties?