Scope Mount Finder

Fit a 30 mm scope in 34 mm rings with reducer inserts

How reducer inserts let a 34 mm ring hold a 30 mm scope, and the direction that does not work.

Needs adapterA 30 mm scope fits 34 mm rings only with 34 mm to 30 mm reducer inserts. Bare 34 mm rings are too large to clamp a 30 mm tube.
Optic30 mm scope30 mm tube
interface
Mount34 mm to 30 mm reducer inserts
seats on
Rail34 mm ringsoversized for a 30 mm tube without inserts
Fit readoutBench figures
Fitment
Insert
34 mm to 30 mm reducer inserts
Direction
inserts step a ring down only, never up
What to fit it with

Reducer inserts drop a smaller tube into a larger ring. A 34 mm ring with 34 mm to 30 mm inserts holds a 30 mm scope, which is useful if you already own the larger rings or a matched mount.

It only works downward. You cannot make a 30 mm ring hold a 34 mm tube. If your scope is 30 mm and you have no inserts, buy 30 mm rings.

Related fitments

Sources: 1in, 30mm, 34mm scope tubes and rings, Weaver Mounts · Scope tube sizes explained, Victoptics · How to select rifle scope rings, Outdoorsmans