The size of a bullet casing lengthens when you fire your gun or resize the casing. You may need to trim the case to return it to proper form. You can reshape and reuse it, and you'll need a case trimmer to do that.
What is a Case Trimmer
Case trimmers are compact devices that hold the ammunition cases while a cutter trims the heads to the precise measurement you indicate. The shells are held in place by collets (bullet-shaped steel pieces) or shell holders (doughnut-shaped pieces). Some manufacturers offer a U-shaped plate with two holes to fit shells for trimming. The collets or shell holders differ according to the trimmer brand.
The Sporting Arms and Ammunition Manufacturers Institute (SAAMI) provides specs for reloading and other information on its website. Following these guidelines will make gunsmithing and using your weapon much easier.
Your ammo’s cartridge case is made of a malleable metal. You’ll need to clip the metal to maintain SAAMI standards with a manual or electric trimmer.
Attach the trimmer to your work or reloading bench to keep cases at the precise length needed for better shooting.
Hornady 50140 Camlock Case Trimmer
Frankford Arsenal Platinum Series Case Trim
Case Trimmer Review
Top Case Trimmer to Prepare for Reloading
Here are three of our favorite case trimmers for everyday use.
Lyman Universal Trimmer
with 9 Pilot Multi-Pack Trims .17 Cal to .458 Cal
The cutter head of the Lyman Universal Trimmer is carbide, the sharpest metal found in a brass trimmer. This cutter features fine grain construction and a universal Chuckhead for holding cases. (It has no collets.) Use it for coarse or fine trimming within 1/1000" of an inch. The Lyman Universal trimmer can cut cases for rifles and pistols up to .458 caliber.
The nine pilots include:
- 22 caliber for .22 Hornet, .222 Remington 5.6x50R Magnum R and others.
- 24 cal for 6mm and .244 Remington, plus many others
- 28cal for 7x64 Brenneke, 7mm Remington Magnum, and others
- 30 cal for .300 Remington Ultra Magnum, .30 Mauser and others
- 9mm for 9mm Luger, .38 Super Auto, others.
- 35 cal for 358 Winchester, .35 Whelen, and others
- 44 cal for .444 Marlin, .44 Magnum, .44 Russian and .44 Special
- 45a for .45 Colt, .45 Winchester Magnum, .45 ACP and others
This trimmer serves even the most ardent marksperson for years. It provides an adjustment ring that allows you to find the right setting and avoid manual changes for repeat sessions.
- No collets necessary
- Includes nine pilots
- Comes with a manual
- The Universal Chuckhead lets you trim calibers from .17 up to .458
- Sharp cutter lasts even after repeated use
- No deburrer or chamfer included
Hornady 50140 Camlock Case Trimmer
- ACCURATELY RESTORES fired cases to the correct length
- MICRO ADJUST CUTTER allows . 001" changes without moving the case
- REPLACEABLE CUTTING HEAD is made of ultra-hard tool steel
The Hornady 50140 has an adjustable cutting head and spindle. It can trim a variety of cases, up to .50 caliber. The pilots included are 6mm, 7mm, 22 cal. 270 cal., 30 cal., 38 cal. and 45 cal. There are four holes for mounting, but there’s no mounting hardware included with the device.
You can change length by 1/1000" increments without moving the case. The trim length is automatically measured from the cartridge head. This trimmer provides square trim mouths, according to one reviewer, and several users praise the Hornady because it attaches easily to their reloading bench.
This trimmer works up to 75% faster than other units to perfect your shells sooner and get you back out in the field.
You have to use Hornady shell holders (except #37) with the 5140. Using other shell holder brands will result in a loose fit. The shell holder won’t index off the case rim; it just pulls the case back onto the bar. The Cam-Lock feature makes it easy to put cases in and remove them.
When used according to directions, the unit won’t twist or flex. Clamp the unit securely to your workbench for best results.
You may need to go through trial and error when you first use this trimmer to get the measurements you need for case length. Once you learn how to adjust the trimmer, you should have no issue working with different calibers.
- Durable, well-constructed
- Has a smooth feel
- Includes a product manual
- Offers a Cam-Lock feature
- Accurate and consistent trimming
- Works with Hornady shell holders only (sold separately)
- Has no marking feature to save measurements
- Lockdown feature is inconsistent
Frankford Arsenal Platinum Series Case Trim and Prep System with Hardened High Speed Steel Chamfer Debur Tool and Primer Pocket Scrapers with Trimmer
- Ease of use: Trimmer indexes cases on the shoulder for speed and precision
- Versatility: Adjustable Collet System works with all shouldered cases from .17 Remington to .460 Weatherby
- Durable: The HSS cutters stay sharp for thousands of rounds to make trimming quick and easy and the heavy-duty motor and...
The LE Wilson CT-SSKIT is a larger trimmer for gun owners who require pinpoint accuracy and need to reshape a high volume of cases. This trimmer has a micrometer that provides accurate measurements while it supports the case body. Use the micrometer's head to adjust the trim length to lengths in .001" increments.
Users praise this trimmer for its ability to trim cases with hardly any burr. The results are consistent, and it keeps the trim length within .0005 inch.
This trimmer includes a durable stainless-steel cutter, crank handle, and case holder. The holder fits .22 to .45 caliber shells with the appropriate holder. A Wilson Logo Stand holds the trimmer. It comes with everything you need except case holders.
Unlike most other case trimmers, it doesn’t use collets or pilots. Mount it in a vise, and use the positive stop feature to trim each case to a standardized length.
- Precision cutting
- Made in the U.S.A.
- No alignment issues or wobbling
- Easy to set up
- Built to last a lifetime
- Not as fast as other methods
- Doesn’t include case holders
A case trimmer resembles a small lathe. It keeps your cases fine-tuned to the proper length, so you can reuse without sacrificing accuracy or power.
All major brands of case trimmers get the job done, but certain models will give you better accuracy in less time. Do your research and consider some of the pointers in this article before adding a trimmer to your workbench.
How to Choose a Case Trimmer
Your buying decision will depend on the volume of cases you'll need to repair, your budget and the quality of the cutting head. Check the case head sizes the device accepts if you need to trim many cases of different calibers.
The choice of a collet or shell holder model is a highly subjective one. Collets may be difficult to use for some people as they may seem bulkier than a shell holder.
Look for the following features when comparing case trimmers:
A collet head holds the case, and a pilot supports the neck. The pilot keeps the case mouth square against the trimmer head. These trimmers are easy to use, but you need to make sure you have a uniform length on all cases.
The case should be tight against the collet's step during the tightening process to stop the case from moving forward and resulting in the wrong trim length.
A power trimmer is mounted to a motor-driven unit that runs the device. These motorized trimmers are best for people who do a lot of case trimming. They leave your hands-free to work on other tasks.
What is Deburring?
After a case trimming session, you should debur the inside and outside of the case mouth. You’ll need a deburring tool to do this, and one may not be included with your trimming device. You can buy a deburring tool online or from big box home improvement stores.
A deburring tool helps ensure accuracy when you trim shells. It removes the sharp edges from case mouths after your trim or turns a neck. Use a double-ended deburring tool to debur and chamfer (cut off a right-angled corner or edge) the outside with one end and the case end with the other end.
Most deburring tools for shells have a 45-degree angle, but a few have a cutter with a 28-degree angle. Some users believe a deburring tool with a 28-degree cutter will improve the bullet’s point of entry.
If you need to trim a large number of cases, you may want to buy a deburring tool that can use a power adapter. With an adapter, you can use a deburring tool with a power screwdriver or drill to deburr case mouths faster.
How to Maintain Your Trimmer
Some trimmer brands need more hands-on care than others, and if you use your trimmer often, be prepared to spend more time cleaning it to prevent poor function. Case trimmers don't need as much maintenance as many other tools.
Brush chips off the cutter and oil the bearing head and crank handle after each use (or as needed if you don’t see much debris). A case trimmer is made from steel and cuts malleable brass, so it will last for years if you clean it properly and re-sharpen it if necessary.
If your cutter starts tearing and leaves a rough finish, it’s a sign you need to sharpen it or get a new one. Avoid this fate by cleaning chips and cuttings after you use your machine.