I use adjustable comb risers
Bolt on one
Strap on butt bag with foam pad,
Shell holder with pads cut from old neoprene waders
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I don't use them for parallax error but so when the butt hits my shoulder the scope is in line with my eye and I don't have to be waggling my head around to find the image. The butt bags with pads are as cheap as $8. on amazon and work just as well as the more expensive ones from the LR houses.