RiverRider
New member
I bought this micrometer screw for my Uni-Flow, probably 10 years ago and have always thought it made using my measure much easier. It's a nice accessory.
This afternoon I was loading up a bunch of .40 S&W for practice. After charging 30 or 40 cases I noticed that the screw had moved somewhat, and the measure was now dropping about 4.4-grain charges of W231 instead of the 4.5 grains I had set up. My micrometer screw adjustment knob had moved out of its setting slightly.
I guess it's a good news/bad news sort of thing since the charge weight was dropping rather than rising. I set the micrometer back to where I started and finished up my loading, readjusting the screw every five rounds or so. I am pretty confident the variances were not enough to make any difference at all from that point on.
When I finished I disassembled the Uni-Flow. I have to admit I could not recall what I had done to install the micrometer screw and I could not find an on-line manual for it, so I loosened the hardware I could see---an allen head set screw on the adjustment knob. That was the right move.
The micrometer adjustment is supposed to keep its setting through friction with an o-ring. When the allen screw is loosened and the micrometer dial is pulled off, you will see the o-ring...it's all very simple. My o-ring had evidently worn some and was not providing enough friction to keep the micrometer knob from turning under vibration. I removed it as carefully as I could and dropped it in a small amount of acetone for a couple of minutes. That seems to have made it swell up a little, I think. It holds the micrometer knob in its setting much better now.
I'll be calling RCBS to see about getting a new o-ring or two, but in the meantime I can continue to use my measure with confidence.
If you're using this accessory, keep an eye on it. I never realized the adjustment knob was getting easier and easier to turn as the o-ring wore, but it sure was doing so and it reached the point of causing a problem.
This afternoon I was loading up a bunch of .40 S&W for practice. After charging 30 or 40 cases I noticed that the screw had moved somewhat, and the measure was now dropping about 4.4-grain charges of W231 instead of the 4.5 grains I had set up. My micrometer screw adjustment knob had moved out of its setting slightly.
I guess it's a good news/bad news sort of thing since the charge weight was dropping rather than rising. I set the micrometer back to where I started and finished up my loading, readjusting the screw every five rounds or so. I am pretty confident the variances were not enough to make any difference at all from that point on.
When I finished I disassembled the Uni-Flow. I have to admit I could not recall what I had done to install the micrometer screw and I could not find an on-line manual for it, so I loosened the hardware I could see---an allen head set screw on the adjustment knob. That was the right move.
The micrometer adjustment is supposed to keep its setting through friction with an o-ring. When the allen screw is loosened and the micrometer dial is pulled off, you will see the o-ring...it's all very simple. My o-ring had evidently worn some and was not providing enough friction to keep the micrometer knob from turning under vibration. I removed it as carefully as I could and dropped it in a small amount of acetone for a couple of minutes. That seems to have made it swell up a little, I think. It holds the micrometer knob in its setting much better now.
I'll be calling RCBS to see about getting a new o-ring or two, but in the meantime I can continue to use my measure with confidence.
If you're using this accessory, keep an eye on it. I never realized the adjustment knob was getting easier and easier to turn as the o-ring wore, but it sure was doing so and it reached the point of causing a problem.