Run Out & O rings

[queen_stick]

FWIW I removed the shellholder retaining clip years ago and replaced it with,,,err,,, nothing.
Takes a little getting used to but my ring finger was'nt doing anything else at the time.

When I get home from work, I'm going to have to try that... never thought about it before. If I don't like it simply sitting there, I'll throw an O-ring on it.

while we're discussing it, I have a small single stage press from Smart Reloader.. the ram has a TON of play in it. I actually bought it for that reason, thinking that it might produce some straight ammo (it was cheap ). I haven't played with it yet to see if all that play is a good thing or bad thing. It seems like a light duty press, so I was thinking about using it for bullet seating and see what happens. One of these days I'll get it mounted and try it out.

Ok guys, I just tried the o-ring trick... in two locations.

Using my 6mm Dasher brass, in a Redding type-s FL die, Lee classic cast press (and shortened shell holder to acquire appropriate shoulder bump.) Removing the retaining clip from the shell holder (replaced it with an O-ring... did nothing, good or bad) I like the idea of allowing that thing to float, so I'll leave the O-ring in. However, adding an O-ring under the locking ring on the die actually increased runout. It wasn't much, but it was enough that I'll choose to leave it out on this die. Without the O-ring I'm getting about .00075 (3/4 of a thou) runout. With the O-ring I was getting between .001 and .00125 of runout... nothing less.

I think the O-ring trick will work in some cases, and might cause more harm in other cases. I'd be willing to bet that some of my other dies might benefit from the O-ring trick, even though it made things worse from my dasher FL die. With that said, I think I'll try the O-ring on each die that I use, and see what it does. If it gets worse I'll leave it off. If it reduces runout, I'll leave it on... it's that simple, and doesn't take much time to figure out.

If the O-ring tricked worked for you once, I'd be hesitant to assume it works for every die you have. Check each one to make sure!

edit: forgot to mention that the brass I tested this with had basically zero runout prior to sizing. Only saw a slight wiggle on the indicator for each piece prior to sizing.

 

[BoydAllen]

Years ago, I made a little fork that was brazed onto a block of steel, that fit into the notch in the top of my Rock Chucker that is designed to accommodate the use of primer tubes. That fork was positioned so that its tines started just below the top of the press, and extended a little farther than the top of a typical lock ring. To this setup, I added an old lock ring that has the set screw hole pointing at the center of the die, and instead of the usual set screw, I substituted a long, round head screw that stuck out longer than was needed to pass between the tines of the fork. With this rather laboriously described setup, I could secure a FL die at any point of adjustment, so that it was completely free to float within the presses threads. the lock ring did not even touch the press but the die could not rotate.

Using this setup, I tried several dies in various calibers. The results were not consistent. Some worked best floating. Some showed no difference, and one worked best locked down tight. I guess that is why we do experiments.

 

[hogan]

Only O-rings I use or have ever used are those integral to the later Lee lock rings. Their lock rings don't fasten to the die body, they rely on an O-ring that fits in a groove on the lock ring to hold the die steady in the press threads.

Only Lee dies I routinely use are their universal decapper units, I have 2 of these along with a couple crimp dies.

Mostly use Redding Type S FL sizers. No point in using an O-ring on the decap rod stop. Might be smart to try one on the decapping stem where it screws into the rod stop. Redding standard decap rod is an integral unit of stem & rod stop. Pretty damn tough to assure that the size button is perfectly in-line with center of decap rod stop. I can't imagine an O-ring correcting any misalignment on those units. Maybe on an RCBS since the rod and rod stop are not integral...