Quoted from PatD:I assumed I was looking for a rubber tip
I think a rod tip is what you want. (https://www.marcospecialties.com/pinball-parts/38-1100W)
The grommet is on the back of the bracket and cushions the solenoid rod. It too could be worn and need replacement.
Unless it is the cam angle, your rod angle appears to be off which would certainly impact strength.
If you don't have the manual, download here, part numbers are listed and should be cross referenced with the big vendors.
https://www.ipdb.org/files/1176/Williams_1986_High_Speed_Instruction_Manual.pdf
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