Seating die tilts to the rear on Co-Ax

[Short Round]

Anyone run in to issues with concentricity errors after bullet seating on a Forster Co-Ax? Not every seating die but a few of them will tilt the top of the die to the rear or rear left when the bullet engages and lifts the die and Forster die ring til the ring hits the top of the die retention slot.

This happens with my Hornady 6.5x55SE die and my Redding 6.8 Rem die. When I check my runout on my Sinclair run out tool it can be quite bad. Over 10 thou runout at the bullet tip. Sorry I don't have all the runout error written down. I measured at the tip and near the neck. I last loaded with the Co-Ax last fall. I went round and round playing with it before switching to my Redding Big Boss press.

I hate to give up on the CoAx but I haven't figured it out to stop the rocking and run out. I took the 6.8 seating stem out and chucked it in my lathe and polished it with one of my bullets to see if matching the tapers would fix the issue. It didn't.

I also would run a sinclair expanding mandrel in the swede cases to see if that would help. The runout comes from the seating though, not the sizing of the brass.

I though about putting a rubber O ring under the lock ring to pre raise the die to the top of the die slot.

 

[marchboom]

I just wonder why only some dies exhibit this trait. If it was something to do with the press it would do this with all dies. My Co-Ax works fine and I get great concentricity.

 

[Weaver93]

I'm not familiar with the press, but should you have enough play between lock ring and slot in press to add an O-ring? Are these the only two lock rings that have the play in them? Are they Forester lock rings? I remember a post on Accurate shooter where someone had the same issue. May have been the lock ring.

 

[Short Round]

Yes, I bought the real Forster rings when this first cropped up. Originally used Hornady lock rings as they were recommended as suitable albeit not as thick.

Maybe more so these dies as they're long and more top heavy?

 

[Weaver93]

Yes, I bought the real Forster rings when this first cropped up. Originally used Hornady lock rings as they were recommended as suitable albeit not as thick.

Maybe more so these dies as they're long and more top heavy?

Here is a link to the Accurate Shooter thread. Maybe it will give you an idea or two.

You are being redirected...

 

[Short Round]

thanks a lot, hopping right over there now!

 

[44-40]

Anyone run in to issues with concentricity errors after bullet seating on a Forster Co-Ax? Not every seating die but a few of them will tilt the top of the die to the rear or rear left when the bullet engages and lifts the die and Forster die ring til the ring hits the top of the die retention slot.

This happens with my Hornady 6.5x55SE die and my Redding 6.8 Rem die. When I check my runout on my Sinclair run out tool it can be quite bad. Over 10 thou runout at the bullet tip. Sorry I don't have all the runout error written down. I measured at the tip and near the neck. I last loaded with the Co-Ax last fall. I went round and round playing with it before switching to my Redding Big Boss press.

I hate to give up on the CoAx but I haven't figured it out to stop the rocking and run out. I took the 6.8 seating stem out and chucked it in my lathe and polished it with one of my bullets to see if matching the tapers would fix the issue. It didn't.

I also would run a sinclair expanding mandrel in the swede cases to see if that would help. The runout comes from the seating though, not the sizing of the brass.

I though about putting a rubber O ring under the lock ring to pre raise the die to the top of the die slot.

Nope, just use the Forester die rings specifically for their press buy em by the dozen, and throw the others in a drawer, when using this press.