So if your slider finger is contacting the case, then the slider may be the cause.
During the last little bit of travel into a shell plate is when it happens when expansion spring is under tension and while still under tension backing out also.
I am/was using new "original" case slider and then the new model "modified" received from Lee and both have the same problem.
It is a known issue at Lee as can be seen by quotes below:
Start of emails:
11/2/22 Stephanie to Gillie Dog
“We are making a modification to the case slider tool to put the case slider closer into the press, parts should be available mid-December”
11/7/22 Jeri to Gillie Dog
“We are tightening up the fitment of the case slider to the rail. The slider, as is now, can slightly rotate on rail, and pull large diameter cases back out of slot, as the case slider returns to the pickup rotation. This tighter fit will prevent this rotation and stop the case from being pulled out of the shellplate.”
12/30/22 Andy to Gillie Dog
“There are .005" raised pads on the retention or lip portion of the slider that make contact with the zinc slide rail. These raised pads tighten up the tolerance and fit to the rail. It may seem perceivable, but they are there and make a difference when loading large diameter cases into the shellplate.”
12/30/22 Gillie Dog to Andy
“ Unfortunately this updated case slider did not cure the drag back issue with 44 mag cases.
Using new Starline brass, a new factory 11L shell plate and the new case slider, cases still get dragged back by the slider. When the slider starts back it tips and the left side of the “loop” on the slider touches the case and drags it back.
I returned to my old modified case slider, ran the same cases again with no drag back.”
End of emails.
Yes, on disassembly of the new and old sliders there are new "raised pads" on the new slider which measure close to .005 thick.
And so I went back to a slider I reworked to match the old sliders which were the large and small from the case feeders before the "Universal" case feeder and am feeding cases without drag back once again. Maybe there will be another shot at it from Lee in the future.
GD