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Alpha V4 Marksman G21 Complete Build Kit
Alpha V4 Marksman G21 Complete Build Kit

Alpha V4 Marksman G21 Complete Build Kit

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On sale: $625.00 $550.00
Retail Price:$625.00
You Save:$75.00(12%)
Part Number: AV4MCBK
Availability: This items is currently on BACK ORDER. If you place the order you will be placed in line to receive one. Free Shipping.

Choose Options

Quantity Price
3 - 5 $495.00
6 - 10 $467.50
11+ $440.00


The PF45 is Polymer80’s next generation of polymer 80% frames for Glock® handguns, bringing improved ergonomics, features and looks to the popular Polymer80 frames.

The Alpha V4 Marksman G21 Slide gives owners a chance to create a customized handgun, exactly suited for any application. The PF45 gives you the chance to build an .45 ACP. 

  • Compatible with Gen3 Glock® Components. Not Compatible with Gen4
  • Improved next generation ergonomics make for a great shooting pistol
  • High strength reinforced polymer construction provides a great basis for a reliable & durable gun
  • Aggressive texture on the PF45 ensures positive retention
  • Picatinny rail is compatible with all standard lights, lasers & accessories
  • Stainless steel locking block ensures positive operation & a lifetime of use
  • Stainless steel drop-in rear rail module interfaces with the slide and holds up to hard abuse
  • Hardened front and rear rail system pins ensure slide/rail/frame interface is rock solid.


  • This Complete Build Kit Includes
  • Complete finishing Jig, Jig includes drill bits and end mill, allowing for complete construction.
  • G21 Lower Parts Kit
  • G21 Upper Parts Kit
  • Alpha Shooting Sports V4 Marksman Slide


The 80% frame features are carried over from the original Polymer80 frames, making your build incredibly straightforward to complete. New grip profiling and improved overall design, make this not only an easier frame to operate and shoot, but looks great mounted to your favorite slide.


No serial number, no FFL required, and no registration needed!


Federal law states that you can build a firearm for personal use. This law has been in effect for years but one knows when or if it will be changed or repealed.


Now is your best time to purchase the Polymer80 lower. This do-it-yourself kit accepts Glock factory parts and we have assembled both a Lower Parts Kit and an Upper Parts Kit to help you build the Polymer80 into a fully functional firearm.


The Polymer80 is the best lower kit available. In fact, at this time, it is the only 80% lower available. Nonetheless, it is very high quality and we've seen many complete guns that have turned out great. We've also seen some that were not finished correctly so it is extremely important that you read and follow the directions.


There are a lot of reasons to purchase an 80% lower. We here to support your choice with the information and parts you need to make it a reality.

The PF45 is compatible with Glock® 20/21 frame components.


No serial number, no FFL required, and no registration needed!

  • Polymer 80 Return Policy

    Returns will not be accepted once the receiver is modified in any way.


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