Factory Replacement O-Rings for SilencerCo Rimfire Suppressors

The SilencerCo Delta O-Ring Pack AC87 provides factory replacement O-rings for compatible SilencerCo rimfire suppressors including the Sparrow, Spectre II and Warlock.

These small sealing components perform an important job inside the suppressor. Depending on the model and location, SilencerCo uses O-rings to help retain components, seal sections of the suppressor and limit the amount of fouling that migrates into areas where it does not belong.

The AC87 pack contains four high-temperature Viton O-rings: two #13 O-rings and two #18 O-rings.

Why Keep a Spare Pack?

Rimfire suppressors live in a particularly dirty environment. .22 LR ammunition produces substantial carbon, powder residue and lead fouling, and the O-rings inside compatible SilencerCo suppressors are exposed to repeated heat cycles, cleaning and disassembly.

SilencerCo notes that O-rings should be replaced when they become dried out, excessively worn, warped or otherwise deformed. Keeping an AC87 pack with your cleaning supplies prevents a damaged O-ring from sidelining the suppressor while you wait for a replacement. :contentReference[oaicite:1]{index=1}

High-Temperature Viton Construction

The Delta O-Ring Pack uses Viton fluoroelastomer, a material well suited to suppressor use because of its resistance to heat and chemical exposure. SilencerCo explains that Viton retains its shape and sealing ability at elevated temperatures and also holds up well when exposed to common firearm lubricants and oils. :contentReference[oaicite:2]{index=2}

That does not make the O-rings permanent. They remain normal wear items and should be inspected during suppressor cleaning and maintenance.

Two #13 and Two #18 O-Rings

Each AC87 package contains:

• Two #13 O-rings
• Two #18 O-rings

These are factory-sized replacement components rather than a generic hardware-store assortment. Using the correct size and material helps maintain the fit and sealing characteristics intended by SilencerCo. :contentReference[oaicite:3]{index=3}

Compatible SilencerCo Models

SilencerCo currently specifies the Delta O-Ring Pack for:

• Sparrow
• Spectre II
• Warlock

SilencerCo's current product page identifies AC87 specifically for these models. This is not advertised as a universal O-ring kit for every SilencerCo suppressor. :contentReference[oaicite:4]{index=4}

Inspect O-Rings During Cleaning

When the suppressor is disassembled for normal maintenance, inspect the O-rings for flattening, cracking, cuts, swelling, hardening or other deformation.

SilencerCo advises against exposing suppressor O-rings to harsh solvents because some chemicals can degrade the elastomer and shorten service life. Follow the cleaning and lubrication instructions in the owner's manual for the specific suppressor. :contentReference[oaicite:5]{index=5}

SilencerCo also notes that O-rings serve different functions depending on their location. In the Sparrow, for example, O-rings around the core help seal the internal half-pipe structure and reduce fouling migration between the core and outer tube. :contentReference[oaicite:6]{index=6}

A Cheap Spare That Can Save a Range Day

The Delta O-Ring Pack is exactly the kind of maintenance part that is easy to ignore until one is damaged or lost during cleaning. Keeping a factory AC87 pack with your suppressor tools or cleaning kit gives you the correct replacements on hand before you need them.

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