PD | Grand Power Slide Optic Milling

Patriot Defense | Grand Power X-CALIBUR Slide Optic Milling

Current Turnaround Time: 3–4 weeks
Service Type: Milling Service only (Customer Provides Slide and Optic)

Service Details

Our Grand Power Optic Milling Service includes:

• CNC-machined optic pocket in your supplied Grand Power slide.

• Rear sight dovetail removal and deck height reduction for a flat, clean install.

• Low sight picture for easier transition from iron sights. (This resolves the common issue with dovetail-mounted optics sitting too high.)

• Recoil bosses included for added rigidity and reduced stress on mounting screws.

• Modified CO Firing Pin Block available Option for purchase (see Additional Fees). Note: The factory FPB will no longer function due to the lowered deck height.

Important Notes

Optic Manufacturer Tolerances:

• Patriot Defense has no control over optic manufacturers’ quality standards or elevation adjustments. Some setups may require a shim to achieve zero. This is common across platforms due to factors like bullet power factor, zero distance, optic design, and elevation range.

→ If you are not willing to potentially use a shim, we recommend using a rear sight mount instead.

Precision Fit Guarantee:

• We guarantee a CNC precision fit between your optic and your slide if the optic is sent with your slide.

• If you do not send your optic, we will test fit using a “shop optic” on hand. Due to manufacturer tolerances, this may cause your optic not to fit correctly.

• If further machining is required, you will be responsible for return shipping.

 Service Scope: This service does not include refinishing or the optic itself. Optional refinishing is available (see Additional Fees).

• USPSA Compliance: A modified Firing Pin Block is required to remain compliant with USPSA Carry Optics rules.

• Slide Preparation: All slides must have the rear sight removed before shipment. Please do not ship your guide rod or barrel.  

• A $25 Armorer Fee applies if Patriot Defense must remove your rear sight upon arrival.

• Optic Shimming: Some ammo/optic/zero distance combinations may require a 1° shim to achieve zero. This is unpredictable and not tied to a single brand or model.

• Precision Fit: We CNC mill every slide to exact tolerances and include recoil bosses when applicable to help centralize the optic and reduce screw stress.

• Optic Screws: We do not manufacture screws and cannot always use oversized factory screws. Screws may wear over time — we recommend replacing them every few thousand rounds. Patriot Defense is not liable for broken, over-tightened, or sheared screws.

Additional Fees

• Slide Armorer Fee — $25
  • Applies if the slide is sent in with the rear sight installed.
  • Covers drilling/removal of stripped or damaged rear sight screws.
  • We are not responsible for damage to the rear sight during removal.

• Modified Safety Block — $20 (If Applicable)
• Provides a replacement modified safety block if required for your setup.
• WARNING: A qualified gunsmith should do final modification with slide and and frame. Please see Firing Pin Block Warning below.

• Optic Pocket Cerakote Refinishing — $40 (For Complete slide Refinishing see: Cerakote Services Here)
  • Optional refinishing service for a clean, uniform finish after milling.

Optic Installation Guidelines

Your optic is not torqued so you can inspect our milling work!

1. Clean Threads – Thoroughly clean the optic screw holes and screws using isopropyl alcohol or acetone. Ensure all oil, debris, and residue are removed.

2. Apply Thread Locker – Apply a small dab of Red Loctite to each screw. Avoid excess to prevent overflow into the optic.  Cure for 24-48 hours before use.

3. Mount Optic – Place the optic onto the slide, aligning mounting holes precisely.

4. Torque Screws – Using a calibrated torque wrench, tighten screws evenly to 12–15 in-lbs. Do not overtighten.

We use an industry-standard thread pitch of 6-32 or M4x0.7 for all optic cuts. Some optics may ship with factory screws that are too large in outer diameter (OD) to fit certain slides. Please follow the best practices below for safe installation.

Thread Pitch by Optic Footprint

• Trijicon RMR & clones – 6-32

• Leupold DPP & clones – 6-32

• Burris FF – 6-32

• Vortex Viper – 6-32

• Vortex Venom – 6-32

• Sig Romeo 3 / XL – 6-32

• C-More RTS2/3 – 6-32

• Shield RMS/x & clones – M4x0.7

• Holosun K Series & clones – M4x0.7

Firing Pin Safety Block (FPB) WARNING (If Applicable to your Slide)

You have chosen to alter your slide from its factory specifications. If you selected the Modified Safety Block, the factory-installed Firing Pin Block (FPB) has been initially modified to accommodate your slide and optic milling. Additional fitting may be required to ensure proper function with your specific frame and slide. A qualified gunsmith must inspect the FPB and firearm before use.

Note: Patriot Defense cannot verify proper function without both the slide and frame present.

Upon receipt of your slide from Patriot Defense services, a qualified gunsmith must inspect and verify the safety block function with the complete firearm before it is used. The following checks are critical:

• ✅ Block Function – Ensure the FPB fully blocks the firing pin unless the trigger is depressed.

• ✅ Sear Interface – Confirm the FPB does not require additional fitting at the sear interface. Improper fitting can cause hammer follow (the sear lifting from hammer hooks when racking the slide).

Note: in circumstances where Patriot Defense has your complete firearm and optic, Patriot Defense will verify proper function before shipping.

Shipping Instructions

• Please include a copy of your invoice with your slide and optic.

• Ship to:
  P.D. LLC
  3352 CR-212
  Anderson, TX 77830

• We recommend insuring your package.

• You are responsible for shipping to our facility. We will ship FedEx 2-Day back to you.

Agreement

By purchasing this service, you acknowledge and agree to all of the above terms.

For any questions or concerns, please contact: customerservice@patriotdefense.com

 Milling Instructions