Primer seating problerm

[NYKenn]

Put the 9mm head back on the Star. Adjusted the seating die. Noticed that the primers were not seating flush with the case and were a few thousands recessed. Loaded 50 as they were and found they worked in a Springfield 1911, but not all worked in a Kahr carry gun. Not even an indication of a light hit on the primer from those that did not work.

Head is mounted correctly, shell plate is installed correctly, as well as primer seat. Machine is over 50 years old, and I have never experienced this problem before in any of the four calibers I reload. Cannot fathom that adjustment of the seating die would be contributing to this problem. What say members?

Plan to dis-assemble and re-assemble the press and head to see if I can determine what the problem might be.
 
Thought perhaps a slight difference in primer seat height ?  I Intend to measure with another before I would consider shortening, but have generally found minimal if any variance in Star parts. Is possible the primer seat could be an aftermarket that came with the 9mm toolhead and be too long? I do not recall this issue the last time I reloaded 9mm (2018 )Maybe will have to get another from RBWillNJ just in case.

Will not have time to do anything before Saturday, so thought I might get some feedback and suggestions.

[NYKenn]

Put the 9mm head back on the Star. Adjusted the seating die. Noticed that the primers were not seating flush with the case and were a few thousands recessed. Loaded 50 as they were and found they worked in a Springfield 1911, but not all worked in a Kahr carry gun. Not even an indication of a light hit on the primer from those that did not work.

Head is mounted correctly, shell plate is installed correctly, as well as primer seat. Machine is over 50 years old, and I have never experienced this problem before in any of the four calibers I reload. Cannot fathom that adjustment of the seating die would be contributing to this problem. What say members?

Plan to dis-assemble and re-assemble the press and head to see if I can determine what the problem might be.
 
Thought perhaps a slight difference in primer seat height ?  I Intend to measure with another before I would consider shortening, but have generally found minimal if any variance in Star parts. Is possible the primer seat could be an aftermarket that came with the 9mm toolhead and be too long? I do not recall this issue the last time I reloaded 9mm (2018 )Maybe will have to get another from RBWillNJ just in case.

Will not have time to do anything before Saturday, so thought I might get some feedback and suggestions.

Could it be the difference of flat versus oval primer punch?

[rbwillnj]

When you changed your tool head, I assume you also changed your shell plate.  It could be that you didn't bring down the shell plate thrust nut as far as it was with the previous setup.   If there is more slack in the shell plate the primer seating depth won't be the same.

Primer depth is controlled by three factors.   Adjustment of the primer punch push rod, slack in the shell plate, and the added force of the expander pushing down on the case mouth.   When I set up a machine, I start by adjusting the shell plate thrust nut so there is just a slight rock in the shell plate, but it turns freely.  Then I back off the expander so it's not part of the equation.   Then I adjust the primer punch push rod to get the proper primer seating depth, then I adjust the expander to get the desired amount of case mount flair.  I you follow this procedure you should be able to change calibers without having to re-adjust the primer seating depth.

Bruce Williams

[NYKenn]

Thanks Bruce

I can rule out the expander, as I tried it without any cases in any stations except for priming.
Nothing changed or is altered that I can see in the primer punch rod, so perhaps it is the shell plate.
As I am going to dis-assemble and re-assemble, I will be attentive to the shell plate when I retighten.

Hope it is something as simple as that!

Regards
Kenn

[NYKenn]

Took the machine apart. Nothing found damaged, bent, impacted, etc. Cleaned it all up, and reassembled.
Also measured the primer punch and it is the same length (.94) as another small punch as well as a large punch.
Re-installed the .9mm head. Primer is till not seating as flush as factory ammo.

Used Winchester SPP primers. Have some Federal and CCI, so will try another brand, but would not expect there to be a height variance of that significance.

Maybe next option is to install the .39spl head and see if that presents the same issue.

[varmintpopper]

KYKenn

The depth of primers is easily adjusted by screwing #44 primer punch push rod up or down on the tool head. this adjustment should come after You have adjusted the Shell plate thrust nut to eliminate up and down movement but still rotate without binding. one other thing You want to do while loading is make sure the crank case handle is rotated all the way down on the down stroke.

Good Shooting

Lindy

[NYKenn]

The issue was corrected by an adjustment of the primer push (#44) rod. I adjusted it up less than 1/8 turn. The primers are now seating just slighting less (.001 - .002) than full flush, but within specs, and are now functioning in the one gun that had ignition issues.

When I first had the problem, I looked at the potential causes. I had checked the primer push rod before dis-assembly and re-assembly prior to cleaning and it was not loose at all. Since the adjusting nut on the push rod was tight, I did not suspect it, and I moved on to checking for debris and found none. I then looked at the length of the primer punch which was within specs.  I appreciate the comment from forum members to provide that second opinion.

I have been using this Star since my father bought it new in 1965. It never ceases to amaze me, the quality of construction, that limits issues. Because of Star quality, it is relatively easy to reduce the cause of problems to one of two minor things and focus on them.  And having the resources form the member of this forum is like having a second set of eyes.

 Thank you Bruce and Lindy!

[starfish]

Great info!