How To Use A Case Trimmer – Beginners Guide

how to use case trimmerCase trimming is one of the most profitable and beneficial approaches for shooters around the glove.

If you have occupied huge time reloading cartridges, then you must know the importance of a brass case trimmer.

When you fire a round, the brass case slightly increases in length from the pressure of firing.

Over the phase of time, the case will extend and need to be trimmed. The trimming is required more often in high-pressure rounds of fire.

As a result, the brass cases stretch out at an extent that it becomes impossible to reload. Trimming plays a vital role in such a situation.


How to Use Case Trimmer

You will be surprised to know that without the right tools and proper method, all your trimming effort may go in vain. So I am here to guide you through the whole process of trimming.

1. Assemble Pilot and Collets in Case Trimmer

Select the correct pilot and collet for trimming the case. Insert the pilot into the cutter shaft and collet into the collet Screw.

2. Insert Case and Adjust for Length

Now, you will have to insert the case and follow the steps mentioned below;

  • With tension on the collet released, insert the base of the case that is going to be trimmed, into the collet.
  • Move the Pilot into the neck of the case. With one hand on the Crank Handle, push the base of the case against the bottom of the collet.
  • Ensure the base of the case is held firmly against the bottom of the collet and the pilot is supporting the inside case neck, then tighten the collet.
  • Ensure the cutter teeth are in contact with the case neck, then tighten the stop collar coarse adjustment-lock screw.

3. Make Trial Cut to Check Case Length

To ensure the case length is accurate, you have to make trial cuts to check and confirm the measurements.

  • Turn the crank handle to make a trial cut.
  • Remove the case and use a caliper to check its length.
  • Consult a reliable manual for correct case length.

4. Make Fine Adjustments for Case Length and Set Stop Collar

To set the stop collar, proper adjustments for the case length is required. Herein, you have to follow the steps below;

  • Turn the Stop Collar Fine Adjustment Screw (one complete turn equals .032″) in case length:
  • A clockwise turn increases case length.
  • An Anti-clockwise turn decreases case length.
  • Once the Case Trimmer is fine-adjusted for case length, lock the Stop Collar Fine Adjustment Screw in place using the Stop Collar Fine Adjustment Lock Screw.
  • Make a final trial cut and check case length. Re-adjust, if necessary.

5. Trim Batch of Cases

Now that everything is checked and confirmed, it’s time to start trimming your cases. However, be mindful of the following;

  • The Case Trimmer is now set up to trim a batch of cases to the exact same length.
  • Occasionally lubricate the Cutter Shaft to Bearing surface with a drop of light oil when trimming.
  • Label and save a master setup case that is trimmed to the correct length for each caliber. This will save setup time in future trimming operations.

Trimming Method with Different Types of Trimmer

Now, I am explaining some excellent processes of trimming your brass with the different types of trimmer that are available for you. Let’s begin with the cheaper side…

Lee Deluxe Quick Trim

Lee has been providing quality products at reasonable prices for long time. The Lee Precision’s Case Length Gauge and Shell Holder permits you to screw a fixed length gauge for a certain caliber in a cutter.

It also allows you trim precisely and to the fixed length. It is modified to bottom out on the shell holder when the length is covered.

Lee Precision’s other version is the Quick Trim Die, which allows you to place a brass case inside a caliber-specific trim die, and put the die into a reloading press.

Finally, with the help of a handheld cutter, you trim the case down using the trim dies to a desired length.

Lyman & Others

Lyman and other producers produce quality trimmers which utilize a hand crank to trim brass cases. Few are micrometer (µm) adjustable with caliber specific pilots that help hold the case in place to ensure a squarely trimmed case mouth.

Once you set the height to the set length, few turns of the crank will be enough to trim brass cases. The steel cutters provide long service.

Frankford Arsenal Case Trim and Prep System

The most popular trimmer is the Frankford Arsenal Case trim and Prep System. It’s an electric power-driven motor trimmer with adjustable rpm dial, & caliber specific collets. The length is micrometer (µm) adjustable, moreover flexible spring-loaded jaws hold almost all rim sizes.

You can use it to trim brass to the smallest case in the batch. And of course, using this system reduces your effort and saves a lot of time. This trimmer will do it accurately and as you know it may be amongst the most costly options.


How to Choose?

Finding the right case trimmer is not a difficult task, but simply just a matter of adjusting your budget with your necessity & your available tool. Putting money on the right thing not only lets you save but also reduces your workload.

The cost for this equipment is tolerable, and I can’t find any good reason to skimp on price, as reloading will surely gain profit subsequently. It doesn’t matter if you have a regular trimmer or an electric powered one, you should ensure the maximum accuracy of your weapon.

Therefore, if you need the best trimmer for yourself, you should look for a trimmer that is user-friendly and available at a reasonable price.



Expert shooters love to trim. A quality trimmer will assist you in saving a huge sum of money in the long run. Because it will abstain you from purchasing fresh new ammunition, especially if you love to shoot at the range frequently.

So, if you are planning for using your brass cases many times, you must buy a brass trimmer.

Joseph Fox

Joseph Fox

Joseph Fox writes on a variety of topics ranging from reloading ammunition to gun cleaning. He has been featured on various publications like thetruthaboutguns, Sofrep & many more. Joseph is also the founder of Gunloading, where he reviews different types of reloading & firearm products available on the market.