Should You Trim Your Pistol Cases?

should you trim your pistol cases

Ammunition is not as cheap as it was 20 years ago. I feel like I’m paying for one .40 S7W round, the same as what a box cost me back then. That’s why many gun owners reload their own ammunition to cut costs and to have a good supply at any time. The debate that always arises is over the consistency of a reloaded round, and you should trim your pistol cases?

Pistol cases, in general, should not be trimmed. Unlike the brass rifle rounds that tend to stretch and need trimming, straight wall pistol cases remain the same length even after multiple reloads. Selected 9mm rounds tend to shrink and, even then, are still within the specified length range. 

If ever you need to trim a pistol case, it would have to be before the first firing. Because pistol cases remain stable for the most part, it is good to experiment with your pistol and a few different rounds to see what happens to the pistol cases. This way, you will get better data to decide if any cases need trimming before reload to guarantee consistent crimping. In this article, we look at pistol case trimming more in-depth.

Do Pistol Cases Need To Be Trimmed?

The consensus in the reload community is divided over the need for trimming pistol cases. On 9mm and .45mm usually do well with extra crimp. This is especially true for revolver rounds. Uniform cases usually produce uniform crimp. 

Many reloaders will conform they never trim pistol cases. Perhaps once only before you start reloading. The neck of the case holds the bullet and not the powder below. Trimming can guarantee that the brass hasn’t moved into the neck. This will push the neck length past the required chamber dimension. 

Trimming can only be beneficial or needed if you crimp and seat in one step; otherwise, it is usually unnecessary.

Should You Trim Your Pistol Cases? 1

Why Would You Need To Trim Pistol Cases?

The only time you would need to trim pistol cases is if the length is over the COL or to assure a tight crimping. There are two types of bullet cases – rimless and rimmed cases; for example, a .45 Colt is rimmed while a .45 ACP is rimless. 

All cases that have been fired would have gone through the “flow” process. This happens when the case gets heated up when the round is fired. Fire forming of a pistol case will not affect it as straight-walled cases keep their length and shape. 

You can measure every case before firing and loading, trim if needed, and after the first firing, you can measure again to check if the length stays the same. This will be your best indicator if you need to trim the case or not. 

Which Pistol Rounds Need More Trimming 

The pistol cases that seem to need more trimming than other calibers are the .40 S&W and .357 Magnum cases. Typically, these cases should get trimmed before the first load and firing to check case length. 

In some instances, these cases can only be reloaded 5 or 6 times before showing signs of wear. Usually, the case splits at the mouth after a few loads. Rounds like 9mm seem to be the casing that never needs trimming but tends to shrink. These cases can usually be reloaded as many times as required. 

Which Pistol Case Trimmers Are The Best?

Whether you’re a newbie at case trimming or have been doing it since sliced bread came about, these are the pistol case trimmers you need to know, 

#1 – Lyman Universal Trimmer Power Pack Combo 7862003 – 

  • Most versatile trimmer
  • Universal trimmer
  • Power adaptor
  • Allows for manual use and adding several power tools
  • Quick setup and conversion between manual and power/ electric

#2 – Lyman E-Zee Trim Hand Case Trimmer – 

  • Best portable trimmer
  • Lightweight, easy carry, and ease of use
  • It comes with a power attachment
  • Includes trim-to-length pilot
  • Includes cutter head
  • Case locking device
  • Can trim any standard case – 44 Magnum, .357, .38, and .40 S&W.

#3 – Hornady Cam-Lock Case Trimmers 050140 – 

  • Best premium trimmer
  • Tall, ergonomic design
  • High-end design and quality
  • Left or right-handed user friendly
  • Secure cam locking for lock and unlock
  • Ensures great consistency
  • Includes the seven most used pilots
  • Changes of 0.001” can be made without the case being moved.
  • It can cater for almost any caliber size. 
Should You Trim Your Pistol Cases? 2

How To Reload Your Pistol Cases And When To Trim

  • Firstly clean the cases thoroughly.
  • Closely check each case for the slightest signs of defects like cracks, bulges, or dents.
  • Discard any cases with a deformed primer
  • With a soft cloth, remove any residue from the inside of the case
  • Give the cases minimal lubrication to prevent them from getting stuck inside the sizing die

#1 – Assemble All The Reloading Supplies You Need

  • Reloading press
  • Case trimmer
  • Cleaned cases
  • Primers
  • Bullets
  • Powder

#2- Measure The Casing According To The Guidelines 

  • Measure each casing according to the COL guidelines
  • Set aside any cases that might need trimming

#3 – Resize / Trim Cases And Remove Primers

  • Insert case into loading press with handle in UP position
  • Lower handle for resizing and expelling the primer
  • Do each casing and set aside
  • Raise the reloader handle to the highest position and insert a new primer.
  • Push primer arm down onto the new primer
  • Remove and inspect. The new primer should be flush or lower than the base. 

#4 – Refill The Casing With The Right Powder

  • Check your recommended powder variant and weight.
  • Use a guidebook that your local gun shop recommends 
  • Using the correct scale, weigh out the powder for each case or use a calibrated dipper.
  • Fill the case using a funnel.

#5 – Seating The Bullet 

  • There is a seating die on your reloader, which pushes the bullet into the neck at the proper depth and then crimps the shell and secures it with the lock ring. 
  • Check the seating, and if it needs to be deeper, you can easily adjust the seater.
  • Clean all the newly reloaded bullets and package them upside down in their holders
  • Clean your equipment and lubricate the dies and all moving parts with a bit of gun oil. 


While many pistol owners agree pistol cases should not be trimmed because they don’t need it, some believe in making sure each case is perfect and within the recommended length limit. 

Whatever side you are on regarding the trimming of pistol cases, if you reload regularly, there is no harm in checking your cases for consistency, and it’s a great pastime. 

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