The Power Custom UPPER/LOWER RECEIVER SHIMS are precision-made AR-15/M16 receiver shims designed to improve alignment and proper fit between upper and lower receivers, ensuring consistent bolt alignment, reduced wear, and reliable operation across a range of components. Crafted to support AR-15 applications, these shims help shooters fine-tune headspace and cheek weld setup by providing clean, stable spacers that maintain a precise plane of interaction between receivers. Built with durable materials and engineered for tight tolerances, the shims promote smooth cycling by eliminating play that can otherwise impact accuracy and function during rapid fire or field use. Whether youre assembling a new rifle, performing routine maintenance, or upgrading a build, these shims integrate seamlessly into standard AR-15 configurations, offering a straightforward solution for achieving a secure, rattle-free fit without modifying parts. Ideal for gunsmiths, hobbyists, and tactical enthusiasts, they support reliable performance in rifle systems that rely on accurate receiver alignment and consistent reassembly after cleaning. Trust Power Custom to deliver a practical, low-profile accessory that enhances fit, function, and longevity of your AR-15/M16 platform.