Primer seating depth issue with Forster Co-Ax press

[Munkey1973]

Hi all,
Has anyone experienced issues with primer seating depth on their Co-ax?

I am using brand new Lapua 308 Palma brass with CCI BR4 primers. Out of box, the brass already had very consistent primer pocket depths before I began reloading, but as an additional measure (and out of habit) I unformed them with my 21 Century uniforming tool... only ended up shaving .0005 to .001 off any given piece of brass.. a polish really.

Using my older, trusted RCBS hand primer with these brass and primers, I am getting a primer counter sink of .007 to .008.

I am certain that I followed Forster’s instructions properly.

But on my Co-Ax press I am consistently getting a perfectly flush (to base) primer seating depth.... Perfectly flat and not getting the .004 to .006 that the Forster manual says that I should be getting.

Wondering if my small primer seater assembly is out of spec.

Anyone else experienced this problem with their Co-Ax?

 

[Munkey1973]

Update with a solution, in case anyone should have this problem in the future and wish to query CGN.

The good folks at Forster advised me that I should gradually back out the threads on the primer seating assembly..... I tried and it worked.
The assembly was turned just a little too far into the top of the press.

My primers are now consistently (very) counter sunk at 0.0035 to 0.004.

 

[bigedp51]

I have a older RCBS bench top priming tool that has very good feel when seating the primers. And you can feel the primer contacting the bottom of the primer pocket.

And if you push any harder you will deform the top of the primer and start to flatten the rounded edges of the primer cup.

My point being some presses do not have the feel that hand tools do. And the anvil must be contacting the bottom of the primer pocket with a slight preload on the priming compound.

Meaning if the primer is not bottom out your firing pin will seat the primer the rest of the way and it may not fire.

Look at the images below and how much the primer pocket depth and primer cup height can vary. Meaning your primers 0.0035 to 0.004 below flush may not have the primer fully seated with the anvil contacting the bottom of the primer pocket. Bottom line, primer cup height and primer pocket depth varies and there is no exact measurement below flush with brands of brass and primers.