Scope Ring Height Testers

Edit: 2026-03-15 - Added some inserts for 1" rings. Haven't printed or tried these myself but should be good. These all start with the file name "insert-1in-".

Edit: 2024-10-03 - Thanks to a nice Redditor, I was alerted that I'd uploaded a version of the rail mount without the screw and nut. Whoops. I've added this and did a quick edit to add the 7mm hex nut version mentioned at the end. 

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Hi there! 

I recently purchased a very expensive scope (an ATACR!) and wanted to get some great rings for it. The annoying thing was that the better rings out there were only available to me through the internet; meaning I had to take a guess at what size would be great.

Lowest isn't always better either! I wanted to get my scope mounted so that my eye was always aligned as soon as I put my cheek on the rest.

Anyway, there are some good versions of this concept out there, but I wanted to put my own take on it. I created this version so you just need to print a couple of the mounts, then the inserts suitable for your scope tube. If (like me) you expect to get a few scope tubes over your years, just print all of them!

Ring heights don't seem to be standardised between brands, so I just made a good spread. 

I'm considering making quite a few versions of this (in 50 thou increments) for 30 and 34mm tubes, but also a few more versions for 1 inch / 25, 35 and 36mm tubes. If you'd like that, drop a comment below.

FYI, here's the rough guide I used:

• 0.90" / 22.9mm = ‘Low’

• 1.10" / 27.9mm = ‘Medium’

• 1.25" / 31.8mm = ‘High’

• 1.35" / 34.3mm = ‘Extra High’

• 1.50" / 38.1mm = 'XX High'

I used a pic rail off a Tikka I had lying around; hopefully that's standard. 

This if you want to use a screw for stability (highly recommended as all printed filament tends to be a bit slippery), I'd suggest socket head cap screws M4 x 35mm. For the nut, try and get a M4 nut with an 8mm hex (I've found that sometimes they'll have a 7mm hex, but I had 8mm on hand so that's what I modeled). Again, drop a comment and I'll add a 7mm version if it's problematic. 

Hope this helps.

P.S. I'm leaving this as a Printables exclusive for the time being. I grew up on Thingiverse but my details got leaked there, so kinda keen not to support them anymore. I really like what Prusa do too.