[gordonmcw]

is it one of the plastic knobs? it's my understanding that they screw off, but they can be difficult. My annies are older, they don't have the removeable knob.

 

[steinie]

If it's the large plastic knob, they do indeed screw off, but can be tough to get off. Many folks have ruined 'em getting 'em off with pliers or such..

Maybe one of those strap wrenches would get it off undamaged??...

 

[tim slater]

Heating the knob will help as anschutz use glue in there, as with the foresight base.

Don't think it really matters what you do to the old one, but people have broken the bolt handle, so take care.