Uniflow Conversion to Quick Change

[GW Staar]

Rather than take over MikeMyer's Uniflow Thread, I need to start a new one on converting a regular Uniflow to the New Quick Change Version (minus the larger hopper that comes with the Quick Change in the store)

In the other thread I posted:

Jesse: I got my conversion parts. They don't come polished and ready to use. I spent 10 minutes with mineral spriits to clean the anti-rust stuff off, buffed the parts and waxed them with plain paste wax. They, the small metering screw, the cylinder and the keeper/plunger thing. Go together smoothly now.

The design is interesting: you have to loosen the alignment pin housing a couple of turns before you can pull the spring-loaded pin to release it. Tightening the housing centers the pin in a hole in the metering screw's sleeve and locks it aligned. Yes I can see why you got impatient with it....not the most pleasant on fingers. There is a hole drilled in the pin housing shaft that would allow you to run a wire through it and make a pull loop.....that would make it easier to release, but not necessarily more pleasant on the fingers. Thinking...

I have decided that I need at least one more measuring screw to test this thing.

The drum is drilled for the large metering screw, so the small metering screw is inside a sleeve....that's how they get one drum to work with 2 sizes of metering screws.

I have reservations on the small metering screw....the sleeve's end doesn't match the drum perfectly at the cavity opening.....so it'll catch a few small powder kernals between the cavity and the sleeve and the cylinder....

Higgite, responded:

GW, do they not match nearly perfectly when the knurled keeper housing knob is tightened all the way? The reason I ask is that I just went and checked mine to see if it does as you described. I found that the contoured end of the sleeve can be either recessed into or protruding from the cylinder hole (depending on how hard you push the assembly into the cylinder) with the alignment pin seated but before the keeper knob is tightened down. But, once the keeper knob is tightened down, the end of the sleeve is almost perfectly smooth with the cylinder. I can feel the slightest lip in a couple of spots with my fingernail, but would be hard pressed to trap any powder at the end of the sleeve. Just FWIW.

Higgite, yes the housing knob is tight, pin is centered in the alignment hole. Tightened metering screw is shown in the following pictures....the powder kernals in each are win. 760 to illustrate the possible problem. The ridge you see varies from .004" to .011". Definitely, it's not flush anywhere.





BTW, I went to Sportsman's Warehouse to try to get a large metering screw and a powder emptying tube, but they don't stock them yet. That means another order to Midway.....and a few days wait to continue the review.

If your fit between the small metering screw and the cylinder is better than mine, I probably should email an RCBS engineer I know, and see if I got a bad metering screw sleeve.....darn....if so the review will be postponed.

If anyone has bought a new Uniflow Quick Change (they are now the same price at Sportsman's Warehouse as the small cavity regular Uniflow) we'd like to know your experience with the small metering screw's fit to the cylinder.....maybe they all match Higgite's good one.

The new Quick Change you buy now includes a bigger hopper, both large and small metering screws, the powder dump tube, and a couple of plastic drop tubes I believe. So far you can't buy the larger hopper at midway....probably requires a special parts order direct from RCBS.

 

[higgite]

GW, the way your sleeve and cylinder match up in the photos (or more accurately, don't match up) is how mine looks when the alignment pin is in the alignment hole in the sleeve with the knob loosened, IF pull on the metering screw. If I push on it, the sleeve protrudes about the same amount. But, in either case, when I tighten the knob, the end of the sleeve aligns almost perfectly with the surface of the cylinder. I think you're right about it being time to contact RCBS. Maybe I just got lucky, but I hate to think a proper fit would depend on luck.

 

[GW Staar]

I hope you aren't that lucky.....actually I hope I was super "unlucky".

I'll Email him with the pictures tomorrow. He's a busy man.....so it might take a few days for a response. The last time I did such a thing I was asked to send him the bad parts and he took care of it, and then some.

 

[David4516]

I recently purchased a quick change measure, had issues with it right out of the box, see related thread:

http://www.thehighroad.org/showthread.php?t=784741

Thankfully RCBS was able to fix the problem but it was discouraging to have that happen right off the bat.

Now I've noticed that they sent me two identical "drop tubes". I was supposed to get one large and one small. I think I have two that are the large size as they don't work for .223 cases...

Looks like I'll need to call RCBS again. Great...

Regarding the small metering screw, on mine at least if you remove it and re-insert it, it will start throwing a different charge weight. I had one set to 3.2gr of bullseye for loading .380 with. Took it out, re-installed it, threw some charges and weighed them. They came back heavy, I think it was 3.6gr or so. I was hoping that I could buy one screw for each caliber I shoot, set them once, and then just change them out. Looks like I'm going to have to fine tune them every time I change calibers. Grrrr

I'm still glad I bought this measure despite these issues (still beats the Lee measure I had before), but I must say I'm not nearly as excited about it as I used to be...

 

[GW Staar]

David, expecting any measure to throw the exact same volume over time is unfortunately not a realistic expectation. There are too many variables that even include humidity, and temperatu.

The best we can expect from a pre-adjusted metering screw, or a written mic setting in a log book, is close. But that's still a big help, since usually just a small quick adjustment is necessary, and the logged or preset screw is a close ball park.

So expect to use your scale every time you get out a preset screw.

As for RCBS's "other" problems, it would seem that they are having a transitional problem with quality control, and packaging errors. More and more companys like RCBS are having to source out part of their inventory to others. That injects control problems that have to be sorted out. Also RCBS like Hornady have added a lot of new products and updated products lately. Again, it takes time to sort out these problems with new products and supply. That's why early adopters have to be brave.....or not be one!

 

[Jesse Heywood]

Just found this thread. Got out the conversion to compare to your measurements on the back side of the metering assy. And I found at least part of the problems I had.

With the metering tightened and the locking pin tight the metering assembly will move .033 in the cylinder under light finger pressure. I can watch the plunger yaw a couple degrees with the movement of the metering assy. This tells me either the pin is too small or the hole in the nut is too big.

The plunger shaft measure measures .125 diameter. I don't have a ball gauge that small, but I was able to slide a #30 drill (.1285) through the nut. I will estimate the hole to be .1300 diameter. Combine that with a bearing length in the nut of .156, allows the plunger to yaw 2 degrees, which explains the movement of the metering assy.

Since my memory isn't working on the details on the incident (other than the part about it not working that well) I will have to assume that it didn't measure consistently.

 

[GW Staar]

I'd be sending that back. Mine isn't overdrilled. It tightens with Zero play....zero. But it just isn't flush. I'll be sending mine to them to fix it....I suggest you do the same.

This reminds me of Hornady's problem with their die bushings a few years ago. They were breaking.....and they replaced a bunch. They were able to rectify the problems with their out-sourced suppliers. I expect RCBS fix these problems too.