Sizing die setup

[NJRaised]

I appreciate the help lately, been asking a lot of questions trying to get back into reloading.

I have a rock chucker supreme and a new set of match master sizing does. Im setting this die up to shoulder bump .002” which is fairly easy to do.

My question…. When screwing the die into the press, there’s slop from side to side , meaning you can kind of rattle the die a little bit in the press. The same kind of happens with the lock ring, when you loosen it on the die, the threads aren’t machined exact to the die. With some of this slop, how do you ensure your die is straight in the press once everything is locked down? I guess what I’m referring to is, how die I ensure the locking ring is squared up to the die and the press. It feels like there’s a lot of room for the die to be slightly misaligned in the press. Obviously once the lock ring is tightened up and die screwed into the press , it’s rock solid. But how do you know that die is totally square in the press. And in that case , if it’s not, does it really matter?

 

[TheOfficeT-Rex]

But how do you know that die is totally square in the press.

Unless you want to start measuring runout- but then you’d have to measure at every stage of reloading, to figure out what’s causing it (which die and step) and if it can be eliminated.

And in that case , if it’s not, does it really matter?

It only matters if it’s really egregious. Quite a few people have tried to test accuracy and it doesn’t matter much, if at all, until you’re at least five and six thou out of round.

There will always be some thread slop until things are tightened down. It should generally end up in ‘good enough’ alignment. There’s even an argument for some movement allowing things to self align and make runout better. IMHO, depending on how much it bothers you, you can ignore it, toss an o ring under the lock ring (like Lee does) to float it, or buy a super fancy perfectly straight press and lock rings.

 

[spife7980]

There is a clearance in the threads so they can move past each other freely, when they get tight they should pull together taking that slop out and self align.
It’s not the cause of your 223s 100 fps issue

 

[straightshooter1]

I appreciate the help lately, been asking a lot of questions trying to get back into reloading.

I have a rock chucker supreme and a new set of match master sizing does. Im setting this die up to shoulder bump .002” which is fairly easy to do.

My question…. When screwing the die into the press, there’s slop from side to side , meaning you can kind of rattle the die a little bit in the press. The same kind of happens with the lock ring, when you loosen it on the die, the threads aren’t machined exact to the die. With some of this slop, how do you ensure your die is straight in the press once everything is locked down? I guess what I’m referring to is, how die I ensure the locking ring is squared up to the die and the press. It feels like there’s a lot of room for the die to be slightly misaligned in the press. Obviously once the lock ring is tightened up and die screwed into the press , it’s rock solid. But how do you know that die is totally square in the press. And in that case , if it’s not, does it really matter?

What some people suggest is putting a rubber o-ring between the locking ring and the press with not too much tightening to let the die have some amount of float so that the die has some self centering. I'm not a fan of this idea as it seems to me it would lead to inconsistent shoulder bumping. For some people, that's simply not an issue as is getting the self centering aspect. Since I use a Forster Co-Ax, I have no way of knowing how the o-ring really performs. But the self centering from the Co-Ax does work very well.

 

[Mike Casselton]

I run a piece of brass into the die before I tighten the lock ring.
If I have to make an adjustment, the lock ring is backed off before running the die deeper. I still have a piece of brass in the die before locking it down. Seems to work for me.

 

[pabrousseau]

You could put a piece of metal with parallel sides on the shell holder and press it against the bottom of your die and lock die ring down. Large nut or sinclare bullet comparator.

 

[918v]

The geometry of the threads causes the die to center itself in the press when tightened. It like forcing a cone upward inside a slightly larger cone.

 

[misser]

is there a device that will prove alignment? and then you found out its misaligned, then what ?

 

[spife7980]

is there a device that will prove alignment? and then you found out its misaligned, then what ?

A lathe with an indicator but youll have a hard time proving its the die and not your set up. So to answer your second question, nothing lol

 

[misser]

i do have a lathe.in my mind's eye I can see how it could/should look. would not be hard to turn . yet there's still that nagging question .
its misaligned, now what ?

 

[KnowNothing256]

i do have a lathe.in my mind's eye I can see how it could/should look. would not be hard to turn . yet there's still that nagging question .
its misaligned, now what ?

In order of cost:
1) Buy a new die
2) Buy a new press
3) Buy a dial indicator and set it up to detect the issue (may be cheaper than #2 depending on the press)
4) Some crazy lathe shenanigans

This is starting to sound like a solution in search of a problem. Verify that you have poor ammo runout before bothering troubleshooting thousandths of inches of misalignment in your press/die setup. And honestly, as mentioned above, you might consider trying to prove that the runout is actually causing accuracy or reliability problems first. To do this, you'd likely need to try to duplicate the handloads on someone else's press, but using your own powder and primer seating steps.

 

[misser]

well i have part of the sceranero. i have 2 rcbs presses, just a matter of using the better of the 2 for sizing

 

[DairyDictator]

It's really a non-issue. Cases aren't held in position with any amount of pressure by the shell plate, so they float per se. The misalignment would have to be pretty damn awful for that to cause issues

The runout that matters is really a function of the die and/or your process moreso the press. For example, expander balls tend to induce more runout because the case is unsupported when it's drug over that ball, meaning neck thickness can have a bigger impact on where that neck ends up. SAC and Forster fixed that by moving the expanding portion up in the die enough that the OD of the neck hasn't left the upper portion of the die before the ID hits the expander.