Genuine Glock 21 or Glock 21SF Upper Parts Kit OEM Gen 1-3 .45 ACP UPK from Marine Gun Builder.

Every Patriot who chooses MGB for their Freedom parts will receive a code shipped with their purchase for a Free Self-Paced Frame Assembly Course at Freedom Crew University.

If you decide not to choose the MGB store, verify your parts from other sellers - Genuine G21 Firing Pins will have 3 hash marks and be stamped 4557. G21 (.45 acp) extractor is marked 1902. It is imperative to use the correct extractor with the right bearing. The extractor depressor plunger 5423 has a center rib for increased strength to absorb the impact for the larger calibers. It will use the Olive LCI bearing 3442. Finally, please prioritize safety and do not attempt PF45 builds with the Taiwan junk parts on Ebay. 

Whether you choose the MGB store to be your Freedom Parts provider or not - we are here to help with any questions.

The internet is flooded with OEM kits that contain counterfeit firing pins, fake extractors, and poorly made springs. These fraudulent parts are unbranded and unsafe. OEM Glock parts are required to pass rigorous manufacturer Quality Controls with extensive test firing and proper safety protocols. The failure rate in our build community using imitation parts is staggering. Read my full Blog post "Glock OEM vs. Knockoffs" to ensure you are buying genuine factory Glock® OEM parts.

MGB Guarantee:

I individually inspect each package for first time quality. When you buy from MGB, you are buying Authentic Genuine Glock® OEM products.

*Note: I will assemble the extractor depressor plunger with Loaded Chamber Indicator Bearing (Olive) for you. Additionally, I will assemble the firing pin components ready for you to drop in.

All Parts in this Kit are G20 factory OEM Glock® and include:

1. Firing Pin SP04557

2. Firing Pin Spring SP00063

3. Spring Cups SP00070

4. Spacer Sleeve SP00056

5. Extractor Depressor Plunger SP05423

6. Depressor Plunger Spring SP33522

7. LCI Bearing SP03442

8. Extractor SP01902 .45acp

9. Firing Pin Safety w/ Spring SP04543

10. Recoil Spring Assembly SP05586

11. Channel Liner SP01148

12. Backplate SP00133

Unmatched Value:

√ Free Shipping

√ Ships within 24hrs (Mon-Fri)

√ Free Self-Paced Course

Glock G21 / G21SF .45acp Upper Parts Kit OEM UPK Gen 1-3 G21 G21SF UPK by MGB

Disclosures & Policies:

1. USA Shipping Only - No International Sales

2. We will not ship to alternate names/addresses - Shipping is to purchaser and address on their billing account only

3. Slides, Frames, Blocks, Rails, or other items in pictures are for illustration only and not included with the OEM Upper Parts Kit.