RCBS Powder measure dangerous

[Waitone]

My initial thought was to check your throw a little more often.

My routine consists of several safety checks
--While pulling the handle on the press I always look down the throat of station 4. I can see the powder level and if anything is wrong, the handle does not get pulled.
--Stop and refill the brass loading pipe
--Pull a shell from station 4 (650XL) and weight the powder charge.
--While the scale is settling out I gage check every round in the bin.
--Gage checking also forces me to inspect the primer, primer seating and check the brass for damage.
--Check the powder weight on the now settled out scale
--Place the checked brass back on station 4 and continue.

If I do have a problem it is limited to 20 rounds of .45 ACP.

Its a pain of a procedure but in 40,000 rounds I've had exactly 1 squib load and no double charges.

 

[BobC]

I must endorse the previous recommendations for the Uniflow micrometer adjustment screw (I have the small size). I initially doubted if it was worth the cost, but have come to really appreciate it.

Adjusting the micrometer unit involves twisting a handle. The mechanism has enough resistance that it doesn't move after I set it.

On the wall in my reloading area I have posted a table of powder measure settings and thrown weight for various powders. Resetting the Uniflow to a new powder/charge weight is now a simple dial in procedure, followed by a weight check which is usually within .2 grain on the first try (for a typical pistol load)

I use a reloading tray for 50 rounds, drop powder into all, visually check for uniform powder height, then weigh the last charge before positioning any bullets.
-Bob

 

[Pumpkinheaver]

Never had a poblem with my uniflow. I visually check every case after throwing powder, then I weigh every 10th or 15th charge to be sure.

 

[Biff]

My Uniflow works well, but I noticed charges becoming lighter by .1-.2gr. as the powder level in the hopper got lower. I make a cardboard baffle that fits in the bottom of the tube and feeds the powder from two notches cut in the sides. This supports most of the weight of the powder column and gives me more consistent charge weights throughout the loading session.

 

[Frohickey]

My RCBS Uniflow came with a folded piece of aluminum to support the weight of the powder column.

Powder Baffle

 

[wingman]

check all screws before reloading, check wt after 25 throws, disassmble and
clean powder measure after 500 rounds. How many clean the powder measure.? It is important and does change your settings.!!!
Loading since 1967 and still learning.

 

[Ala Dan]

My RCBS "Uniflow" didn't come with a baffle; but
I made one out of a piece of scrap aluminum. All
I have too do is insert it atop the powder thats
in the hopper; and it rides down as the powder
is used. Hey, it works great; as I used it while
loading some .45 ACP's just yesterday 02-23.

Best Wishes,
Ala Dan, N.R.A. Life Member

 

[Frohickey]

How would a powder baffle that rides on top of the powder column give you consistency? Unless its the percentage weight of the powder vs the aluminum powder baffle. So, if the aluminum powder baffle is 6 ounces, and the powder column when its full is 1 ounce, and when its almost empty is 0.1 ounce, you have a variance of 6.1 ounces to 7 ounces of weight.

I think you will have better consistency if the baffle is at the bottom. That way, the 6 ounces of baffle is sitting on the metal part of the powder measure, and you have a constant powder column under the baffle thats always the same weight and pressure.

 

[Mal H]

I've gotta agree with Frohickey on that one, Dan. The baffle is intended to be used at the bottom in order to keep the weight on the measuring cavity a constant no matter how much or how little powder remains in the main tube.

 

[SwampFox]

250 rounds?

If you don't have a bullet puller this is when it will pay for itself.

 

[bigjim]

Fluids

MalH said: I've gotta agree with Frohickey on that one, Dan. The baffle is intended to be used at the bottom in order to keep the weight on the measuring cavity a constant no matter how much or how little powder remains in the main tube.

doesn't the powder flow inside the tube making it act like a fluid?

If so then a baffle at the bottom would not impact the "weight" of the powder pressing down.

Could some one please explain the science on this one?

I know Dillon uses a wieght on top of the powder to act as a low powder sensor but it also helps even out charges.

 

[Mal H]

I'm not even close to having enough fluid dynamics under my belt to give the scientific explanation. But, the way I understand it (read "my guess is"), since the baffle has the 2 holes to allow powder to pass on the edges of the baffle, the weight of the column doesn't directly impinge on the measuring cavity. That is, the force vector is to the side of the cavity. If powder acted as true fluid, then this would most likely not be the case. But, it is non-fluidic enough to make it work.

 

[P95Carry]

My 2c here ...... the powder is particulate ... and IMO does not ''flow'' in a fluid sense unless aggitated continuously .. when it might behave like sand particles for instance, which can mimick fluid behavior then. Flour can also do this.

The propellant powder particles are, whilst usually coated with graphite to help flow .. still marginally cohesive .. quite minor but, they need movement plus gravity to get something akin to flow.

In my turret Lee for example ... before the powder hopper gets round to the flare/charge station again ... it has received three minor ''shocks'. One on release of the lever at that station ... again when bullet seated and once more when depriming and sizing next case.

The only thing that is a major variable ... and here using a fluid metaphor ..... is the ''head'' of powder .. the weight above bearing down on the base of the column where it will enter the measure bush. At each aggitation we could see this as brief ''fluid'' flow .... but that ceases once static again.

There is a logic to the low baffle with side slots .. because it has a damping effect on the flow from top to base of column. Pressure is force x area ... and so if the main column ''head'' of pressure is let's say, borne by a baffle of 90% the CSA of hopper (the slots giving the 10% passage rights!) .. then when the powder is static, it is bearing most of the weight of said column. .... that ''head''. The slots limiting volume flow rate as things settle each time.

I have long made it a habit to operate the lever and ram at bottom of stroke after each charge - a sorta ''double tap'' ... to ensure settlement of powder and a good and total filling of the bush, ready for next ... without usually any baffle in fact. My thinking there is that aglomeration or compaction of powder particles with really a very modest weight above (''head''!) is minimal . We are after all measuring volumetrically.

If a hopper was huge and contained a whole pound jug of powder I might be more concerned between full and near empty states. The baffle probably comes into its own when throwing real small charges ... as maybe you would need for 32 S&W target loads ... pretty critical then ... in fact when I loaded those years ago I used a dipper anyways and weigh-checked too come to think of it.

Powder type too will affect things ... from the extreme on one hand of large flake (Unique) to very fine ball (H-110).

OK ... only 2c of waffle!

 

[Guy B. Meredith]

You might like adding an RCBS powder check die to your press if using a progressive. Locks up the press on overloads.

 

[budman46]

uniflow measure

bigjim--
my uniflow adjustment screws tend to loosen from the banging of the lever. i check the tightness every 10 rounds or so...nothing elaborate, just try to turn them tighter...if they don't move, i keep going. at the end of the loading block i check the weight on the last charge to make sure everything is ok.
budman.

 

[Sludge]

You were talking about throwing 250 rounds away. Couldnt ya just weigh a few (10 or so) known good rounds and then determine an upper limit and set your scale for that. Start weighing the 250 and kicking out the ones that exceed the variance you gave them? Use the bullet puller on those that failed and reload em.

 

[budman46]

sludge--

the difference in charge weights is only 1.3 grains...there's more variation in lots of brass than that, not to mention cast bullets, so your method wouldn't be a safe bet.

budman

 

[cracked butt]

Try running your bad rounds up into a single stage press with no die screwed in. Use a pair of wire cutters to grip the bullet and move the ram down to pull the bullet. It will ding your bullets up a bit, but won't be a total loss, and its much easier than using one of them "hammer" bullet pullers.

 

[bigjim]

Buttcrack said: Try running your bad rounds up into a single stage press with no die screwed in. Use a pair of wire cutters to grip the bullet and move the ram down to pull the bullet. It will ding your bullets up a bit, but won't be a total loss, and its much easier than using one of them "hammer" bullet pullers.

That is a great idea!!! How did you come up with it?

 

[Clark]

I don't have a baffle in my Uniflow.
I just keep topping it off like a girls drink.


That Uniflow green see through plastic got cloudy from Power Pistol trying to eat it.
Other than that, it is a pretty good measure.

 

[Larry Ashcraft]

A burning garbage truck cannot be a pretty sight...

Garbage truck drivers all have the same instructions for a burning load..."DUMP IT NOW!"...wherever, whenever. Now that would not be a pretty sight. Trash trucks are expensive.