Patriot 80% 1911 Commander Size Parts Combo

Pick Your Caliber & Color

Add a Stealth Arms 1911 Jig For $149.99

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Diamondback 300 Blackout


Barrel: Diamondback Barrels 300 BLACKOUT Carbine Length, 16 in., Medium, 4150 CrMov, Black Nitride

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80% Sig Sauer Pistol Parts

P320 Compact 9mm Luger 3.9″

Includes: Built upper, Frame, Lower Parts Kit, Pistol Case

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Glock 17 Slide
Glock 19 Slide

Due to recent events, processing and shipping times have increased.

JT-15 Complete Rifle With 80% Lower

AR-15 California Compliant Rifle

The Juggernaut Tactical Rifles



G17 Stripped
G19 stripped


80% Sig Sauer Jig - P320 Compatible - MUP 1

In stock
Product Details


This is a Pre-order

Modular Universal Pistol 1 Completion Jig

Operations Required to Finish:

  • All Holes
  • Bend Slide Rails
  • Trim Rails to Size

Jig Kit Includes

  • Jig
  • Top Plate
  • Drill Bits


2 Side Plates 1 Top Plate 7 Drill Bits 4 Bolts

Recommended Tools

  • Dremel
  • Vise
  • Drill Press
  • Files

MUP-1 Jig Instruction

1. Assembling the jig

1.1. Place the two side plates together and secure them with the provided bolts. Do not tighten all the way.

  1. 1.2. Place the 80% MUP-1 Receiver into the jig. Ensure the receiver bottoms out in the jig.
  2. 1.3. Tighten the bolts.

2. Bending the slide Rails (approximate .860” from outside of rails)

  1. 2.1. Secure the jig in a vise with the rail tabs sticking up towards the ceiling.
  2. 2.2. With the receiver bottomed out in the jig, and the bolts tightened, place the contoured end of the top plate in between the first set of rails. Be sure that the ‘top’ of the top plate is now facing the ejector pin in the 80% MUP-1 receiver, so that you don’t bend it as you start the rail bends.
  1. 2.3. Using a hammer, pound the top plate down to start the bending process of the slide rails.
  2. 2.4. Repeat step 2.3 for the second set of rails. PLEASE NOTE! This first step only starts the bend for each set of rails.

2.5. Loosen the bolts slightly, and with the receiver still in the jig, place the top plate down in to the receiver. Be careful to assure the top plate is aligned such that the ejector is not being contacted by the top plate.

  1. 2.6. Tighten the bolts and place the jig on its side into a vise.
  2. 2.7. Squeeze the vise closed until the top plate fully bends the rails on to the side plates and bottoms out. Both front and rear rails need to bend to the side plates. If need be, use a punch to finish the bend of all 4 rails flat to the side plates.
  1. 2.8. Remove the jig from the vise and rotate it so the rails are facing up again.
  2. 2.9. Using the line marked on top of the side plates as a cutting guide, remove the excess material on the slide rails using a Dremel.

3. Drilling Holes
3.1. Keeping the top plate and receiver in the jig, place the fixture on its side and squeeze it in a vise so that the top plate is bottomed out and rails are again tight to the side plates
3.2. Drill all the corresponding holes. We recommend using a drill press, but a handheld drill may work as well.
3.3. Drill one side, then the other side. DO NOT DRILL FROM ONE SIDE THE WHOLE WAY THROUGH TO THE OTHER SIDE.

NOTE! The two closely-spaced #40 holes are intended to be a slot. Cut out the material between the two holes.

4. Trigger and Safety Slot

4.1. While the receiver is in the jig (Opening where you used the 7/32” bit), use a Dremel with a cut off wheel to open the trigger slot. This opening needs to have enough material removed to allow the trigger to pass through that opening.

4.2. On the opposite side of the trigger slot, you drilled 2 small holes (#40). Using a Dremel or a file, remove the material between those holes to make 1 opening.

5. Final Steps

  1. 5.1. De-burr all holes.
  2. 5.2. Contour (if necessary) and de-burr the slide rails. On occasion, the Dremel method does not remove enough material to allow the MUP-1 to fit inside the slide. If this happens, remove material using a metal file or Dremel little by little on both left and right sides to ensure a proper fit. If you are using a Dremel, use it at the lowest speed and go slowly – you can always take more material off, but you can’t easily add more on.

6. Assembly

6.1. Using the parts you’ve acquired, assemble your completed MUP-1 receiver. There are several videos online; at the time of this document’s writing, check out our video at the top it will take you through the whole process:

“SIG Sauer P320 FCU/Lower Reassembly”
6.2. Using your Cal-X kit (or other grip and slide assembly), function-check your firearm to assure

that the trigger function works, and resets as desired. 6.3. Take your new firearm to the range and enjoy!


Customers ordering items that are illegal and or we have been advised not to ship to the state they are in will have their orders cancelled and will be charged a 5% restocking fee.

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U.S. Patriot Armory (USPA) is a veteran owned small business located in the city of Apple Valley (Just North Of Ontario California). Our mission is to be your go-to source for quality firearm products by offering exceptional quality at competitive prices. USPA has everything you need to be prepared for uncertain circumstances. Protecting your family’s well-being is your top priority and being prepared for anything will give you an unprecedented advantage. We are a one stop destination for top of the line firearms, parts, tools, survival accessories, and kits to ensure you’re never caught off-guard regardless of the circumstances. We take the safety of our customers very seriously and we stand behind the quality of every product we offer. Our team is always available to help you find and select the perfect product.

PRICES: Online pricing & inventory may vary from in-store pricing & inventory. | COLORS: Colors viewed on the website may be inaccurate due to monitor miscalibration.


Under the Gun Control Act (GCA), shotguns and rifles, and ammunition for shotguns or rifles may be sold only to individuals 18 years of age or older.

US Patriot Armory abides by all state regulations regarding the sale of 80% Lowers.

It is the CUSTOMER’s responsibility to research and understand laws regarding the ordering and shipment of 80% lowers to a state region in which the customer order’s from or ships to.

If an order containing an 80% lower originates or ships to the following states or regions, the customer will be charged 18% of the total invoice amount in which the 80% lower is listed.
















US Patriot Armory abides by all state regulations regarding the sale of high capacity magazines.

It is the CUSTOMER’s responsibility to research and understand laws regarding the ordering and shipment of high capacity magazines to a state or region in which the customer order’s from or ships to.

If an order containing a high capacity magazine deemed illegal originates or ships to the following states or regions, the customer will be charged 18% of the total invoice amount in which the high capacity magazine is listed.

  • California — No magazines greater than 10 rounds.

  • Colorado — No magazines greater than 15 rounds, effective July 1st, 2013.

  • Boulder — No magazines greater than 10 rounds.

  • Connecticut — 10 Rounds and less with a valid permit.

  • Hawaii — No magazines greater than 10 rounds.

  • Illinois (North Chicago) — No magazines greater than 16 rounds.

  • Aurora, Skokie, Chicago, Evanston — No magazines greater than 15 rounds.

  • Highland Park,Cook County,Dolton,Homewood, Deerfield—No magazines greater than 10rd

  • Deerfield — No shotgun magazines over 5 rounds.

  • Maryland — No magazines greater than 10 rounds October 1st, 2013.

  • Massachusetts — No sales. USPA will not ship ANY items to the state of Massachusetts.

  • New York — No magazines greater than 10 rounds.

  • New Jersey — No Sales

  • Vermont — No magazines over 10 rounds will be shipped as of April 13, 2018.

  • Washington D.C. — No Sales. USPA will not ship ANY items to the District of Columbia.

USPA will not ship high capacity magazines for CA customers to a High Capacity Magazine Dealer.
High Capacity Magazine Dealers in CA must place orders with USPA directly.

U.S. PATRIOT ARMORY does not under any circumstance provide legal advice or legal counsel. It is the customers’s responsibility to research their respective City, State and Federal laws in the area they are ordering from. We DO NOT provide gunsmithing advice. U.S. PATRIOT ARMORY is not responsible for improper builds, damage or injury due to user error. Experienced Gunsmith installation and proper new round break in period recommended.

Law enforcement officers must provide both their credentials and a letterhead signed by their department’s superior officer stating that the magazine will either be used in the execution of the L.E.O.’s duties, or off duty. USPA only recognizes City Police Officers, County Sheriff Deputies, and State Police (including Highway Patrol) as L.E.O.’s.

CALIFORNIA WARNING: Proposition 65 Disclaimer Proposition 65, officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, requires businesses to inform California consumers about exposures to specified chemicals prior to purchase. Listed below are the products we offer that are subject to California’s Proposition 65 based on notifications we have received from our manufacturers. You may also download this list which includes the warning message via our download files which can be found online in the “Dealer’s Toolbox” under “Available Downloads”. This list will be updated regularly as we receive additional information from manufacturers. Please visit for additional information regarding your obligations under Proposition 65.

No products will be sold or shipped to residents of the state of NEW JERSEY
No AR-15 parts will be sold or shipped to residents of the state of NEW YORK only ships within the United States of America