CO-AX Press Shoulder Control - Die Shims or Shell Holder

[Herd_Bull]

I'd like to try some type of shim for better shoulder bump control in my Co-AX press. Either the Redding Competition Shell Holder Set or the Larry Willis Innovative Technology Precision Die Shims.

I know with the Redding set I need to remove the spring loaded S-jaws and replace with a standard shell holder plate adapter that will accept the shell holders, don't know if this would be worth it or would take away some of the advantage of the free floating ability of the S-jaws???

I use Hornady lock rings on my dies and there's not a lot of room in the press slot to fit a die shim once the die is installed...??? Is this even something I should consider?

Any feedback is appreciated. Thanks.

 

[BoydAllen]

There are multiple issues involved in the pursuit of consistent bump. Die setting, which is what die shims address, is not one of them, for your press, they would have to be placed on top of the lock ring, and that would be problematic, since you would loose your lock ring setting every time that you changed your shim, or shim pack, unless you could assemble them to the die from the top without moving the lock ring. Other issues are consistency of annealing, consistency of lube application, dwell time at the top of the press stroke, and linkage stretch or compression variations. Redding makes competition shell holders that can be used to create a slight toggling effect so that linkage issues can be reduced. Yes using shell holders would seem to eliminate one of the advantages of your press, but I have not used a shell holder on one so I could be wrong. Some years back, we were able to resolve a shoulder bump issue for a couple of magnum calibers, by using a properly set up two torch annealing machine. By playing with the dwell time we were able to make the bumps much more consistent, and still have adequate neck tension for heavy recoiling calibers in hunting rifles with magazines. This was for a friend who uses the same press that you do to size, without the shell holder conversion.

 

[Mr Underbridge]

Wouldn't it be simple to just get a custom die?
My redding FL bushing die barley sizes my brass fired in Palma 95 chamber too.

 

[Comrade Terry]

Forster sells bump dies. I use one, and it does the job.

http://www.forsterproducts.com/product-category/sizing-dies-bushing-bump-neck-sizing-dies/

 

[PatMiles]

Wow, I didn't know Forster make an adapter to use individual shell holders in place of their sliding shell holder. This opens up some new possibilities.

 

[danny]

You could probably use die shims if you thin the die lock ring enough to be able to take the amount of shims needed within the casting recess that the die lock ring slides in. as indicated, you would need to place the shims on the top if the lock ring.

Danny

 

[danny]

I'd like to try some type of shim for better shoulder bump control in my Co-AX press. Either the Redding Competition Shell Holder Set or the Larry Willis Innovative Technology Precision Die Shims.

I know with the Redding set I need to remove the spring loaded S-jaws and replace with a standard shell holder plate adapter that will accept the shell holders, don't know if this would be worth it or would take away some of the advantage of the free floating ability of the S-jaws???

I use Hornady lock rings on my dies and there's not a lot of room in the press slot to fit a die shim once the die is installed...??? Is this even something I should consider?

Any feedback is appreciated. Thanks.

It would not be much work to surface grind the lock ring a bit, but you need a surface grinder

Danny

 

[Dusty Stevens]

Or just get another press thatll do the stuff that one cant do. The coax is not a stand alone press for a serious reloader. It has too many limitations

 

[danny]

Or just get another press thatll do the stuff that one cant do. The coax is not a stand alone press for a serious reloader. It has too many limitations

It is not a do all press, I agree. It is not the answer for all people, either. I love mine, but I know this about it.

Danny

 

[waldo1979]

Does the headspace really float that much on a Co-Ax? Everyone time you remove the die and place it back do you have to adjust the lock ring? You'd think it would be a set it and forget it operation.

 

[danny]

Does the headspace really float that much on a Co-Ax? Everyone time you remove the die and place it back do you have to adjust the lock ring? You'd think it would be a set it and forget it operation.

It is set and forget.

Danny

 

[TimP]

Does the headspace really float that much on a Co-Ax? Everyone time you remove the die and place it back do you have to adjust the lock ring? You'd think it would be a set it and forget it operation.

There is no such thing as set and forget when it comes to shoulder bump at least in my experience.

 

[Liven The Dream]

Never used Coax , have a friend that went almost Nuts trying this shoulder bump with one ?????
Went to Redding Boss and He is almost normal ? I am not a Doctor and haven't stayed at a Holiday Express .

I have used a RCBS Rock chucker and Redding Boss for years shoot Palma and 1000 . I have no trouble loading good Ammo with .001 run out .
I move the shoulder back .002 to .003 for my chambers.
The only problem a few years back was a out of spec. Foster Die. Replaced it with a Redding . ( best not to reinvent the wheel at times )

Best of Luck

 

[waldo1979]

There is no such thing as set and forget when it comes to shoulder bump at least in my experience.

I'll have a little fluctuation in headspace between pieces of brass but not anything significant. How much fluctuation are you seeing? Now I'm 2nd guessing myself and will have to measure every piece of brass after resizing.

 

[fguffey]

There are multiple issues involved in the pursuit of consistent bump. Die setting, which is what die shims address, is not one of them, for your press, they would have to be placed on top of the lock ring, and that would be problematic, since you would loose your lock ring setting every time that you changed your shim, or shim pack, unless you could assemble them to the die from the top without moving the lock ring.

And I wonder if anyone ever measures the distance between the top of the shell holder and bottom of the die. And then there is the assumption the shoulder is bumped back; I find that most difficult to do, more times than not the shoulder on my cases do not move. I fired a 8mm57 round in a 8mm06 chamber; had the shoulder of the case moved the case would have been ripped apart.

F. Guffey

 

[waldo1979]

There are multiple issues involved in the pursuit of consistent bump. Die setting, which is what die shims address, is not one of them, for your press, they would have to be placed on top of the lock ring, and that would be problematic, since you would loose your lock ring setting every time that you changed your shim, or shim pack, unless you could assemble them to the die from the top without moving the lock ring...

If you use the Hornady C-clamp style lock rings this isn't an issue. If your using the classic lock ring that doesn't have a set screw or a Lee style o-ring lock ring then this is an issue.

 

[fguffey]

Wouldn't it be simple to just get a custom die?

And then there is a remote possibility a reloader could learn to custom adjust their dies.

F. Guffey

 

[ireload2]

HB
Boyd Allen mentioned some of the things that affect shoulder bump.
One of the ways you can learn to deal with them is to take a large lot of cases and form them to another configuration while measuring the shoulder location of each and every case as you form them. You will find small variations caused by the temper of the brass and your own technique.
1. Speed of the sizing stroke.
2. Amount of lube used and consistency of application - consistency of amount and where applied to the cases
3. Dwell time at the top of the press stroke.
4. Number of press cycles. Yes you can cycle the brass at the top of the stroke multiple times with small rotations of the case between strokes. These cycles will keep moving the brass a few .0001 per stroke until it quits moving. These extra strokes and the extra dwell time give the cases enough time to quit creeping and take a set at the die setting. I normally see little change after 3 strokes so that is about my limit. (If I am trying to measure and record the dimension that I attribute to the die as manufactured I might use more strokes and a second round of lube just to find out the shortest possible case that can be produced by a given die.)

Fast single strokes and inconsistent technique will easily see at least .002 to .003 variation over 100 cases. Extra forming time from multiple slow strokes, rotation of the case between strokes, consistent lube application and dwell time at maximum stroke of 3 to 5 seconds will remove nearly all of the .002 variation in shoulder location. The variation will be so small you will probably need a .0005 or .0001 dial indicator to actually see the difference.

If you do not own such a set up use your stripped bolt to check each case. I look for a tiny amount of drag when closing the bolt with a single pinky finger.

 

[Herd_Bull]

Thanks to everybody for all the good responses. Lots to consider for sure. Boyd Allen and ireload2 you guys sound like folks I could learn a lot from. Thank you. I'll be taking another good hard look at my process and see if I can tighten things up.