DIY zero stop for SWFA 5-20?

[LancerTIC]

I went with the shim method. Thanks for the tip with the garden hose washer, that was a good fit. I then added these from Amazon (https://www.amazon.com/dp/B0G3491NPQ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1), but they were basically 18mm ID and 25mm OD flat washer shims. Just don't make the mistake I did and think you can just turn the turret to check the zero-stop setting without screwing the retaining screw down. I had just held onto it so it'd turn, which is fine, but when I hit zero, it would then slip, so now I need to go back to the range and re-zero the scope.