How to Convert a CZ 457 to Another Caliber - East Ridge Outdoors

How to Convert a CZ 457 to Another Caliber

One of the best features of the CZ 457 platform is its interchangeable barrel system. Instead of buying a second rifle, you can swap barrels and convert your rifle to another caliber in about 30 to 45 minutes the first time you do it.

After you've done it once or twice, the process is straightforward and can be completed in around 10 minutes.

I recently converted my own CZ 457 from .22 WMR to .22 LR. Here's exactly how I did it.

What You'll Need

  • Compatible CZ 457 barrel
  • Correct magazine for the new caliber
  • Magazine spacer (required when converting to .22 LR)
  • T25 Torx bit or screwdriver
  • 3 mm hex bit or Allen key
  • A gun cradle makes the job easier, but isn't required. I used a front and rear shooting rest to support the rifle.

For more information on the parts required and compatibility, I covered it in another article.

Preparing for a CZ 457 barrel changeover from 22 WMR to 22 LR

Step 1: Remove the Bolt

Open the bolt, push the release and slide the bolt out the rear of the action.

CZ 457 with the bolt removed preparing for a barrel change

Set it aside where it won't get dirty or damaged.

Step 2: Remove the Action from the Stock

Turn the rifle upside down.

CZ 457 upside down to remove the action and barrel from the stock to perform a barrel swap

Using a T25 Torx bit, remove the two action screws:

  • One behind the trigger guard
  • One in front of the magazine well

CZ 457 Bottom screws to disassemble the action from the stock

As you remove these screws, be ready to support the rifle. Once they're out, the action and barrel will separate from the stock. If your rifle has a scope installed, take extra care not to let it fall or hit the bench.

Lift the action and barrel free from the stock.

CZ 457 action and barrel removed from the stock

If the screws fall out, don't worry. The long screw installs in the rear, while the short screw installs in the front.

Step 3: Loosen the Magazine Guide

Using the 3 mm hex bit, loosen the two screws holding the magazine guide in place.

CZ 457 Barrel screws and front magazine guide screw

These screws do not need to be removed completely.

If you loosen them too far, the silver spacer assembly may become loose or fall out. If this happens, that's perfectly fine. Reinstall it by aligning the threaded section at the rear with the rear magazine guide screw.

If you completely remove both screws, remember:

  • Long screw in the rear
  • Short screw in the front

Step 4: Loosen the Barrel Screws

Using the same 3 mm hex bit, loosen the two angled barrel retaining screws.

CZ 457 Barrel screws and front magazine guide screw

Loosen them fully, but don't remove them.

If one comes out accidentally, thread it back in a turn or two.

Step 5: Remove the Barrel

Slide the barrel straight out of the receiver.

CZ 457 action with the barrel removed

Mine required a little wiggling before it came free, but it wasn't difficult.

If the barrel doesn't move, double-check that the angled retaining screws and the magazine guide screws have been loosened sufficiently.

Step 6: Install or Remove the Magazine Spacer

This step depends on which direction you're converting.

Converting from .22 LR to .22 WMR or .17 HMR

Remove the retaining pin and pull out the magazine spacer.

Converting from .22 WMR or .17 HMR to .22 LR

CZ 457 magazine guide with 22 LR spacer installed

Install the magazine spacer into the magazine well and insert the retaining pin to secure it.

Don't tighten the magazine guide screws yet.

Step 7: Install the New Barrel

Before installing the new barrel, I found it easier to flip the action right-side up. This allows the silver magazine guide assembly to settle into its proper position.

Slide the new barrel into the receiver.

CZ 457 with a 22 LR barrel being installed

It may require a little wiggling—and possibly a bit of pressure—but it should seat almost completely flush.

Step 8: Tighten the Barrel Screws

Once the barrel is fully seated, tighten the two angled barrel retaining screws.

CZ recommends 48 in-lb of torque if you're using a torque wrench.

If you don't have one, they can be tightened securely by hand with a standard screwdriver or hex driver.

Once the barrel is secure, tighten the two magazine guide screws.

Step 9: Test the Bolt

Before reinstalling the stock, slide the bolt back into the action.

CZ 457 Action with the bolt installed

Cycle it several times to ensure everything operates smoothly.

If something doesn't feel right, now is the easiest time to correct it.

Step 10: Reinstall the Stock

Place the barreled action back into the stock.

Reinstall the two T25 action screws.

Remember:

  • Long screw in the rear
  • Short screw in the front

Tighten both screws securely.

CZ 457 switched over from a 22 WMR to a 22 LR

Finally, cycle the bolt one last time to confirm everything functions correctly.

Final Thoughts

That's all there is to it.

It's hard to believe how simple CZ made it to convert a 457 to another caliber. My first conversion took around 45 minutes as I learned and took pictures of the process. Now that I've done it once, I could comfortably complete the conversion in 10-15 minutes.

If you're considering converting your CZ 457 instead of buying a second rifle, I definitely recommend it. Just remember that you'll need the correct barrel, magazine, and—if converting to .22 LR—the magazine spacer. Once everything is installed, all that's left is to head to the range and sight in your new barrel.

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