How to Fit 1911 Barrels

by Scott Friedman
The 1911 .45 caliber pistol

The 1911 .45 caliber pistol

Installing a fitted match grade barrel into your 1911 can improve the accuracy of your firearm while decreasing the likelihood of jams. Although you can pay a gunsmith to fit a match barrel into your 1911 .45 caliber pistol, it isn't hard to do this for yourself. The main goal of custom fitting your barrel is to ensure the barrel returns to the exact same spot after each shot, which is the key to increasing accuracy.

Measure the space between the slide lug bearing surface and the barrel hood using a caliper.

Measure the hood length with the hood length gauge. Make note of the difference between this measurement and the one in the previous step.

Measure the barrel hood width and the the width of the slide's barrel hood slot.

Use Dykem blue to mark the sides and hood of the barrel. Then use the barrel alignment block and a bushing to check how well the barrel fits so far.

Polish the slide's interior with your lug iron focusing on the parts where the Dykem blue from the barrel marked it the most.

Place the slide in the barrel block and clamp it under your milling machine. Mill the proper hood length and width to fit your slide. Remove the barrel each time you make substantial cuts to check how the barrel locks into the slide. Remember you can't uncut a custom match barrel if you've gone too far.

Align the barrel with the barrel alignment gauge and inspect the location of the firing pin port with the barrel installed in the 1911 after each adjustment, until the barrel alignment gauge fits properly into the firing pin port.

Use the throat chambering reamer to adjust the chamber headspace.

Mill the proper bottom lug foot height on the barrel and repeatedly check the fit whenever you make substantial cuts. Continue to mill and adjust until your 1911 barrel is fitted.

Items you will need

  • Calipers
  • Hood length gauge
  • Barrel alignment block
  • Milling machine
  • Barrel block
  • Barrel alignment gauge
  • Throat chambering reamer
  • Dykem blue layout fluid


  • If you have the skill level you might want to use a hand lug cutter instead of the mill to adjust the bottom lug foot height as this allows you to adjust while the gun is mostly assembled.

About the Author

Scott Friedman is a writer based in Bend, Ore. Friedman was a technical writer for a USAID contractor and a community health system. He writes for various magazines and websites while running a proposal development firm, BDC International. He holds a B.A. in international affairs from George Washington University.

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