Unless I'm mistaken, the pellet cup on a speedline vac filler unit is built into the end of the plunger itself. Much like the lock down filler units.
The standard vacumatic units have a black pellet cup on the end of a translucent or black plunger rod. There are ways to rebuild the standard units but generally it's more PITA than it's worth. Drop $20-25 on a good used unit & call it a day. Try Ernesto Soler at parker51.com. he may have a stray filler unit he could sell you.
Also are you talking about a speedline vacumatic or a speedline 51?
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Tu ne cede malis sed contra audentior ito ~Yield not to misfortunes, but advance all the more boldly against them
It's a Vac, not a 51. Following Ron Zorn's suggestion I have now made a suitable replacement, I may have misdescribed my filler unir, it has a clear plastic plunger and did have the black pellet cup on the end.
Right on. Ron is a good repairman & has made some interesting tools.
The speedline filler ia an all aluminum unit the standard unit is the same your description. I have seen them with clear, yellow/clear, amber/clear and solid black plunger rods.
Did you buy a new one or come up with a fix?
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Tu ne cede malis sed contra audentior ito ~Yield not to misfortunes, but advance all the more boldly against them
I made up a replacement using parts of a Pentel Gel pen refill. The end where the ball unit fits into is exactly the same diameter as the plunger and the pellet is a snug fit into it. It works well enough.