How to Install AR‑15 Bolt Catch

Installing the bolt catch on your AR‑15 lower receiver is a vital step that ensures your rifle locks back reliably after the last round. This guide covers tools, process, and pro tips for a clean installation—even if it's your first build.

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🧰 Tools & Parts Required

• Lower receiver
• Bolt catch
• Bolt catch spring
• Bolt catch plunger
• Bolt catch roll pin
• Roll pin starter & finish punches (or roll pin punch set)
• Ball peen or brass hammer
• Vise block and bench vise
• Masking or blue painters tape

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🔧 Step‑by‑Step Instructions

1. Secure your lower receiver in a vise block to hold it steady without marring the finish. It’s smart to apply masking tape around the catch area to avoid scratches

2. Install the bolt catch spring and plunger into the left side of the lower, just above where the magazine catch sits.

3. Position the bolt catch in the channel between the roll pin ears, then use a starter punch to hold it lightly in place—punch in from right to left .

4. Begin inserting the bolt catch roll pin from the opposite side, using a roll pin holder or starter punch to align it without bending .

5. Finish driving the pin flush with a properly sized finish punch, tapping gently to avoid deformation.

6. Test the assembly by slightly pulling the bolt catch outward to confirm proper spring tension and smooth movement.

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🧠 Pro Tips and Tricks from the Community

• Use a small amount of grease on the pin to make installation smoother and easier.

• A toothpick or wire insulation can hold the roll pin steady during start-up before tapping it in:

  “Use a toothpick to guide the pin from the mag well side.”

• For a controlled, non-marring pinch, use channel‑lock or vice‑grips wrapped in electrical tape:

  “Channel locks wrapped in electrical tape …push the pin in.”

 

🔗 Tools & Parts Mentioned in This Guide

Looking to complete your bolt catch installation? Check out these essential parts and tools:

• AR-15 bolt catch spring – Provides the tension needed for proper engagement
• Deltac roll pin punch set – Ideal for AR builds and roll pin installs
• Roll pin punch sets – Professional tools for clean, scratch-free assembly
• AR-15 lower parts kits – Includes bolt catch and other critical components
• AR-15 gunsmithing tools – Build, upgrade, and repair your rifle with confidence
• Armorer’s tool kits – Full sets for serious builders and pros

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💡 Frequently Asked Questions

Q: What size roll pin punch should I use?
A: Use a #3 roll pin punch (≈ 3/32″) for most AR‑15 bolt catch roll pins. A starter punch helps align before final seating.

Q: Can I skip the starter punch and tap the pin directly?
A: You can—but a starter punch, especially a coiled roll pin starter, greatly reduces risk of bending or misalignment .

Q: How do I prevent scratching the lower receiver finish?
A: Apply blue painters or masking tape around the pin and lower area, or wrap grip surfaces (like channel locks) with tape before using them .

Q: Will the bolt catch spring fall out during installation?
A: Not if aligned correctly. Installing spring and plunger first, then immediately positioning the bolt catch keeps everything in place.

Q: What if I don’t have dedicated punches?
A: Alternatives like taped‑over channel locks, needle‑nose pliers, or even small hex wrenches can work if pressed carefully—just take it slow and avoid damaging parts.

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✅ Why This Method Works

Following this method ensures accuracy, prevents damage to your lower receiver, and gives a clean, reliable bolt catch install. It’s what seasoned builders do to save time and avoid frustration—even on tight builds.

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