Mounting Rifle Scopes can become confusing when navigating through the world of available riflescope rings and bases. Two common questions when it comes to mounting rifle scopes are; “Will my Weaver style rings fit a Picatinny rail/base?” and “Will my Picatinny rings fit a Weaver style base?” The short answer to these questions is “Maybe” and to understand this answer, you must first understand the differences.
Historically, Rifle Scopes and accessories manufacturers developed their own systems for attaching to firearms. Everyone had their own idea of how best to mount their optics. In the mid 90s, there was an explosion of optical technology and the military was looking for a standard mounting system to attach accessories to weapons quickly and easily while maintaining accuracy. They wanted to be able to remove and reattach accessories without going through the time consuming process of re zeroing the equipment.
For this, they tasked the Picatinny Arsenal. The Arsenal was asked to develop a standardized system for mounting optics and other accessories. In doing so, they gathered various popular mounting systems available at the time, measured them, and averaged the measurements. They added some tweaks and modifications, tested, retweaked, remodified, and the MIL-STD 1913 rail was born. This Mil standard is typically called the Picatinny rail.
So what does this have to do with mounting rifle scopes? The dimensions that were settled on are very similar to that of Weaver. Principally, the width is nearly exactly the same. The primary difference between the two style mounts is in the recoil lug. The recoil lug is the crossways slots in the mounts which keep the devices from sliding forward during the recoil of a firing event. The recoil lug is larger, more frequent, and more evenly spaced in the MIL-STD 1913 rail offering a greater flexibility for rifle scopes, tactical sights and other accessories. So, generally, Weaver style rings will fit on a Picatinny style base whereas the converse is less likely to hold true. Where this does not hold true is with rings that straddle the base and do not lock within the recoil lug and there are some Picatinny rings that are thin enough to fit within the recoil lug. Also, many shooting accessories are now designed to fit both Style Bases.
When ordering rings and bases to mount your rifle scopes and other shooting accessories, the safe choice is to, where possible, remain consistent. Choose Weaver Style Rings matched with Weaver and the same with Picatinny style rail. Otherwise you run the risk returning to get bits and pieces trying to fit a miss matched system.
As a little helpful hint, be sure to use a medium strength thread locking material when securing those pieces of your mounting system that you won’t be frequently undoing. This will help keep the rifle scopes from vibrating loose during shooting and transit.