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USC to UMP Conversion

There are two methods for the Ump conversion: the Block Style bolt up solution and the Rear Section Fuse method. The rear section fuse is the most authentic and allows for a push pin breakdown, like the factory UMP and is dimensionally identical. The block method is a bolt up solution, which adds approximately 3/8 of an inch to the LOP and will still allow the firearm to be reverted to its original form. For the most authentic conversion the rear section method is desired. The average conversion labor cost is $750. For the block method the average conversion labor cost is $300.

The cost breakdown is as follows:

  • Mill all five UMP style vents. $75
  • Add the stock hold open ledge. $75
  • Convert the UMP lower, including opening the hooks, filling the catch block, per ATF spec, and converting the fire control group or swapping in the USC controls. $75
  • Add UMP demilled rear section (must be four inches long) and refinish receiver. $400
  • Add NFA engraving. $40
  • UMP style markings. $75
  • Cut down and thread, crown barrel to 16mmx1LH. $75
  • Mill UMP carrier to fit USC or US made receiver. $45
  • Custom Duracoat project with two mags and any single color, including laser engraving the markings on the lower. $350 (Color fill is an additional $50.)
  • Dye grey USC. $35

All service work does not include the return shipping cost. The typical turn around is two weeks or less on full conversions.

Required parts list for conversion:

  • Demilled rear section with UMP push pin or stock block with pin
  • UMP lower complete (if you buy a stripped lower, you will need the mag release, mag release axle for either conversion. Also, the buffer plate is required for the rear section style conversion.
  • Stock
  • Stock axle pin

This conversion does require the project to be 922R compliant. Three parts are needed. The USA made magazine counts as all three parts and is the most popular. There are many other compliant part options available at HKparts.com as well.

If you have the parts and are ready to have the work performed, fill out a work order and follow the instructions on the shipping page. If you have any specific questions or requests feel free to email tom@tommybuilttactical.com.