AR15 vs LR308 Magazine Release: Key Differences
By Texas Precision Optics Inc | Published: 2026-10-17
Category: Comparisons
Learn the main differences between AR15 and LR308 (AR10) magazine releases, including fit, compatibility, and trade-offs for your build.
Quick Answer
AR15 and LR308 (AR10) magazine releases are not interchangeable. The LR308 uses a larger magazine catch and release button to accommodate the wider magazine body. If you are building an LR308, you need a dedicated LR308 magazine release assembly. Using an AR15 part will not work.
Why the Magazine Release Differs Between AR15 and LR308
The AR15 platform uses a standardized magazine catch designed for 5.56 NATO/.223 Remington magazines. The LR308 (often called AR10) was designed for the larger 7.62 NATO/.308 Winchester cartridge, which requires a wider magazine body. This difference in magazine width means the magazine release mechanism—specifically the catch, button, and spring—must be physically larger on the LR308 to properly engage and release the magazine.
While the basic operating principle is the same, the parts are not cross-compatible. Attempting to install an AR15 magazine release on an LR308 lower will result in the catch not reaching the magazine notch, causing the magazine to either not lock in or release prematurely. Conversely, an LR308 release on an AR15 lower will likely bind or not fit the bolt catch.
Key Trade-offs
- AR15 Magazine Release: Smaller catch and button. Designed for 5.56 magazines. Not compatible with LR308 lowers. Stick with AR15-specific parts for your AR15 build.
- LR308 (AR10) Magazine Release: Larger catch and button to fit wider 7.62 magazines. Not compatible with AR15 lowers. Must use LR308-specific assembly for your LR308 build.
- Cross-compatibility: Magazine release is one of the parts that does NOT cross over between AR15 and LR308. Other parts like end plates, buffer tubes, and grips often do. Always verify part compatibility before purchasing; do not assume AR15 parts work on LR308.
Product Facts
- AR-15 Magazine Release Assembly LR-308: The AR-15 Magazine Release Assembly LR-308 from Texas Precision Optics Inc includes (1) Magazine Release, (1) Magazine Release Spring, and (1) Magazine Release Button. Brand: Texas Precision Optics Inc. This assembly is specifically labeled for LR-308, confirming it is the correct size for the larger platform. It is not an AR15 part, so you must ensure your lower receiver is LR308-compatible.
- AR15 Sling End Plate Ambidextrous Single Point Vertical Loop: The AR15 Sling End Plate Ambidextrous Single Point Vertical Loop is constructed of all steel, replaces the original factory receiver end plate, and installs easily in minutes. While not directly related to the magazine release, this end plate is a common upgrade for both AR15 and LR308 builds. It shows that many small parts like end plates are cross-compatible, unlike the magazine release.
Which One Fits Your Build?
Best for
- Builders assembling a standard AR15 in 5.56/.223
- Anyone upgrading or replacing a worn AR15 magazine release
Not for
- LR308 (AR10) builds requiring a larger magazine catch
- Builds using 7.62 NATO/.308 Winchester magazines
