Rifleman Q&A: Riflescope Shims

by
posted on September 16, 2022
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
Qa

Q. I was attempting to sight-in a Winchester Model 94 side-eject rifle in .30-30 Win. using a telescopic sight. The shots printed high with the elevation cranked all the way down. Am I right to conclude that placing shims under the front telescopic sight base should correct this problem? How many shims of what thickness would be required?


A. Shimming the front base will depress the barrel relative to the line of sight. The old formula is the sight radius in inches, divided by the range in inches, times the error at the target. To get an idea of the thickness needed, this formula could be modified, substituting the distance between the rings for the sight radius. Maximize the scope’s range of adjustment by determining the error at the target with your elevation adjustment set near the middle of its limits.

­—John Treakle


This “Questions & Answers” was featured in the February 2006 issue of American Rifleman. At time of publication, "Questions & Answers" was compiled by Staff, Ballistics Editor William C. Davis, Jr., and Contributing Editors: David Andrews, Hugh C. Birnbaum, Bruce N. Canfield, O. Reid Coffield, Charles Q. Cutshaw, Charles M. Fagg, Angus Laidlaw, Evan P. Marshall, Charles E. Petty, Robert B. Pomeranz, O.D., Jon R. Sundra, Jim Supica, A.W.F. Taylerson, John M. Taylor and John W. Treakle.

To subscribe to the magazine, visit the NRA membership page and select American Rifleman as your member magazine.

Latest

Sw Mp Spec Series Web
Sw Mp Spec Series Web

Review: Smith & Wesson Spec Series V M&P 9 Metal HD

This latest enhancement from Smith & Wesson proves that good things can come from heavier, steel-framed packages.

Old Glory Bank, NRA Partner To Provide Banking Benefits To Members

Old Glory Bank and the National Rifle Association (NRA) recently entered into a joint marketing relationship to provide banking benefits to members of the NRA Business Alliance and NRA-affiliated clubs and associations.

Rifleman Review: Taurus Expedition

Taurus entered the bolt-action rifle market with its Expedition, a Remington 700-pattern design that's built to be versatile and affordable.

New For 2025: Charter Arms Pathfinder II

Charter Arms updated one of the oldest models in its lineup with the new Pathfinder II, which features a lightweight 7075 aluminum frame, making it more well-balanced and easier to carry.

Review: Kimber 2K11

The 2011-style pistol was designed to address the capacity limitations of the single-stack M1911 platform, and Kimber's approach to the concept is its 2K11, a competition-ready offering with several notable features.

Favorite Firearms: A High-Flying Hi-Standard “A-D”

Manufactured in New Haven, Conn., in late 1940, this Hi-Standard pistol was shipped as a Model “A,” but a heavier Model “D” barrel was installed later to replace the original, light barrel, leading one American Rifleman reader to call it a Model “A-D.”

Interests



Get the best of American Rifleman delivered to your inbox.