Tried most rings available for download and found that none is perfect, is allot about customization (individual physiology) and also personal preferences so i decided to design myself one based on turkish/ottoman design... at the end resulted in 2 models, thinner one (1) require a bit of sanding for perfect fit but appears to give a bit better control, wider one (2) works straight out of the printer. For me those are working great, don't pinch, good control and accuracy so if you did not found a good one give a try of this (is fast ~15-20 min/pcs and can be done from leftovers since is taking ~1m filament). Trying other rings i found that if it string pinch you can fix it by printing few percent bigger on Y axe and glue a thin piece of leather on the lip (exemplified in last 2 pictures using a patch of an old piece of glass cleaning leather, yes is not need to be tick or strong, i think it may work with cloth too but i did not tested) so if it pinch you try that but in my trials worked great without the leather lip. How to make-it fit: For me, model 1 works as it is but it need some sanding, model 2 (wider one) works best scaled 95% on X axe (100% is a bit too wide and it feels a bit inaccurate on shooting) and 100% on Y and Z or if i add the leather scaled 95% on X, 104% on Y and 100% on Z. Added a better version of pointy one (1b), is supposed to work without any sanding but is a bit scaled down. Added a new version (V3) in 2 sizes, may look a little lite but is actually quite good when you find the perfect size, on this the idea was to feel like you shooting without a ring