OSA Premium Upper Parts Kit (UPK)
The OSA Premium Upper Parts Kit includes the highest-quality components needed to complete your AR-15 upper receiver. Manufactured in the USA by Forward Controls Design (FCD), this kit replaces standard mil-spec components with precision-machined upgrades designed for improved durability, cleaner aesthetics, and enhanced functionality.
Whether you're assembling a premium duty rifle or upgrading an existing build, these are the exact parts we trust on our own rifles.
Includes
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Forward Controls Design Low Snag Forward Assist (LSFA) (Dimpled or Serrated)
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Forward Assist Roll Pin
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Forward Assist Spring
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Forward Controls Design Billet EPC (Ejection Port Cover)
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Ejection Port Cover Rod
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Ejection Port Cover Spring
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Ejection Port Cover C-Clip
Features
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Genuine Forward Controls Design components
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Precision-machined billet EPC
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Low Snag Forward Assist (LSFA)
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Available with dimpled or serrated forward assist
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Made in the USA
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Premium fit and finish
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Compatible with standard AR-15 upper receivers
Our Thoughts
Most upper parts kits are an afterthought.
They include the bare minimum mil-spec parts simply because every upper receiver needs them.
We wanted something better.
That's why our OSA Premium Upper Parts Kit is built entirely around Forward Controls Design components—parts that are exceptionally well made, thoughtfully engineered, and built to withstand serious use.
The LSFA (Low Snag Forward Assist) is one of our favorite upgrades. Its low-profile design reduces the chance of snagging on gear while still providing positive engagement when needed. Choose between a dimpled or serrated button depending on your preferred look and feel.
The Forward Controls billet Ejection Port Cover (EPC) has become one of the most recognizable premium upgrades in the AR community. Beyond its distinctive appearance, it offers excellent machining quality and a noticeably tighter fit than many standard stamped covers.
While these upgrades won't make your rifle shoot tighter groups or faster splits, they do elevate the overall quality of the build. The controls feel more refined, the fit and finish are outstanding, and every component is manufactured to a level that's well above typical mil-spec parts.
Why We Chose Forward Controls Design
There are countless upper parts kits available, but very few are built using components we'd choose for our own rifles.
Forward Controls Design has earned a reputation for producing some of the highest-quality small parts in the industry. Their attention to machining, tolerances, and long-term durability is second to none.
That's why these are the parts we install on our premium OSA builds.
Final Verdict
If you're building a rifle where quality matters, don't overlook the small parts. The OSA Premium Upper Parts Kit replaces ordinary mil-spec hardware with premium components from Forward Controls Design, giving your upper receiver the same attention to detail as the rest of your build.
It's a simple upgrade that delivers exceptional quality, outstanding fit and finish, and the confidence that every component on your rifle was selected for a reason.
