21st Century hydro bullet seater

Truck Fireman

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Minuteman
Jan 27, 2019
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Looking to buy one of these. Hopefully I can find one that someone wants to get rid of before I buy new.

How are you guys liking them? Are you seeing much improvement with separating difference is seating pressure? Thoughts?

Thanks!
 
This is not a press for the novice. It goes 0-100 PSI and it’s designed for light neck tension applications, like benchrest, not your typical reloads. It is problematic with compressed loads. You don’t know if the seating pressure is from the neck friction or the powder fighting the bullet. It is very sensitive and provides great feedback.
 
I’m hoping it will give me better feel if seating. I’ve recently switched to a coax and I can’t get consistent seating depth to save my life. I just have no feel and if I’m seating the bullet the same each time.
 
I’m hoping it will give me better feel if seating. I’ve recently switched to a coax and I can’t get consistent seating depth to save my life. I just have no feel and if I’m seating the bullet the same each time.
Either your neck tension from case to case is off (either a sizing die issue or an annealing issue) are you using a mandrel after sizing? or your seating die is messed up, what seating die are you using?. What measuring device are you using as well? Are you measuring OAL or BTO? I load all my precision rifle rounds off a coax (as well as hundreds others on here) and I have no problem getting consistent seating depths.
 
You’re likely to, “feel” less with a hydraulic press. There’s no substitute for direct mechanical linkages when it comes to feel.
what you gain is the gauge to tell you if you’re pressures are consistent, but if you’re having inconsistent seating depths, I’m wondering if it isn’t something else that’s the issue.
I use a Rockchucker and have never had my depths vary. Run it down ‘till it stops and bring it back up again.
 
I was having zero problems getting consistent seating depth with my Lee turret press. Switch to a Co-Ax and can’t get it consistent to save my life. Using the same dies for both 6bra and 223. Same comparator, same everything. Only change has been the press.
 
I was having zero problems getting consistent seating depth with my Lee turret press. Switch to a Co-Ax and can’t get it consistent to save my life. Using the same dies for both 6bra and 223. Same comparator, same everything. Only change has been the press.
Interesting. Only way to figure it out is to go through everything one by one. But I don't think you need a whole new press to solve the problem because the press is used by so many.

Did you switch all your die lock rings to the Forester ones specifically for the CoAx Press?
 
I was having zero problems getting consistent seating depth with my Lee turret press. Switch to a Co-Ax and can’t get it consistent to save my life. Using the same dies for both 6bra and 223. Same comparator, same everything. Only change has been the press.
There’s yer prallem. You need to use difernt dies for 6br and 223.
 
Yes sir. Using the Forster lock rings. I’m baffled.
Are you using a mandrel to set neck tension? I'd check the depth of that next to make sure the mandrel is making it's way down the entire neck. If it wasn't sizing the entire neck that could change seating depth depending on when the bullet hits resistance or not of the part of the neck thats "unsized" by the mandrel.
 
I didn't particularly care for the 'feel' of the K&M system - the bellville washer stack felt too 'squishy', and robbed the process of pretty much any 'feel', and the correlation of compression (in thousandths of an inch) to psi is only approximate.

I don't have a 21st Century press, but I do have a hydraulic *base* for my K&M, from Dale Carpenter. Basically it replaces the OEM base plate, with a heavy machined base that houses a hydraulic cylinder. As you seat the bullet with your hand-die, it presses down against the cylinder and the pressure reads out on the attached gauge.

That way you can cull out the ones with too much or too little neck tension.

True... to an extent. While neck tension can play a part, the surface condition of the neck ID plays at least as big of a part - the consistency of the friction - in what you 'feel' here, and what the gauge shows you.

I was having zero problems getting consistent seating depth with my Lee turret press. Switch to a Co-Ax and can’t get it consistent to save my life.

If that's the case, you have something weird going on that you need to fix first, before you switch to an arbor press of any flavor.

I just have no feel and if I’m seating the bullet the same each time.

Very odd... is your Co-Ax stopping with the die touching the shell plate, or with the yoke arms contacting the frame stops?
 
It is contacting the frame stops with the seating die installed leaving a touch of the seater sleeve still out.

Are you using a mandrel to set neck tension? I'd check the depth of that next to make sure the mandrel is making it's way down the entire neck. If it wasn't sizing the entire neck that could change seating depth depending on when the bullet hits resistance or not of the part of the neck thats "unsized" by the mandrel.

Yes sir I am using a mandrel. I know it’s going all the way through on my 223 and it’s close on my bra but I measured and it is getting full expansion.
 
I know on my old Lee press, depending on how fast and hard I sent the ram up it would change seating depth. I was able to feel to slow do or add a little extra on the Lee. On the co ax it seems like it’s all or nothing. I try to go slow and I try to go fast but that last bit of the press on the co ax goes when it wants.

Sizing is excellent on the co ax.
 
It is contacting the frame stops with the seating die installed leaving a touch of the seater sleeve still out.

Try leaving a little more of the sleeve exposed, i.e. not compressing the spring quite as much. Unscrew the die out of the lock ring another full turn. If you have turned down as far as it sounds, there may be some edge/corner of the die body touching the housing for the shell plate.
 
Try leaving a little more of the sleeve exposed, i.e. not compressing the spring quite as much. Unscrew the die out of the lock ring another full turn. If you have turned down as far as it sounds, there may be some edge/corner of the die body touching the housing for the shell plate.

I’ll give it a try. Thank you.
 
The other thing to watch out for, particularly with the Forster and similar 'clamping' style die rings (Whidden, Lyman, etc.) is that you don't have anything protruding from the ring, or if so, that that protrusion is facing forward, towards you. If something sticks out to the side or rear of the U-shaped slot for the die, then the die may not line up with the shell holder quite right, and it can cause all manner of problems.

That can also happen with some other kinds of dies - usually I've had issues with expander mandrel dies that were intended to sit low in a Rockchucker, not in a Co-Ax - so the die has to be screwed 'out' further than normal so that the top clears the U-slot. In theory, something similar could happen with the wider portion of a micrometer/sleeve seating die...
 
The other thing to watch out for, particularly with the Forster and similar 'clamping' style die rings (Whidden, Lyman, etc.) is that you don't have anything protruding from the ring, or if so, that that protrusion is facing forward, towards you. If something sticks out to the side or rear of the U-shaped slot for the die, then the die may not line up with the shell holder quite right, and it can cause all manner of problems.

That can also happen with some other kinds of dies - usually I've had issues with expander mandrel dies that were intended to sit low in a Rockchucker, not in a Co-Ax - so the die has to be screwed 'out' further than normal so that the top clears the U-slot. In theory, something similar could happen with the wider portion of a micrometer/sleeve seating die...

Got it. I always keep the screw portion of the ring facing out.
And my expander die is definitely out more than I want it to. I may have to put it in another press to get it to work to where I’m comfortable.
 
If it's a K&M expander 'plug' (not really a 'die' in the usual sense) they do make a 'riser' body, with a cut-out window. Works well for elevating the expander a bit, both so it gets the knurled portion up above the frame of the Co-Ax, and to get it up where you're operating in the range of max mechanical advantage so the the whole expanding process is a lot easier.
 
I’m hoping it will give me better feel if seating. I’ve recently switched to a coax and I can’t get consistent seating depth to save my life. I just have no feel and if I’m seating the bullet the same each time.
Try taking the handle off. I had same problem, I now operate my coax with no handle, have a much better feel for seating.