The folks at PMA Tool, makers of arbor presses, neck-turning tools, and other case-prep tools, offered some good advice about case trimming on the PMA Tool Website. Here we reprint a PMA article that explains case trimming basics and helps you choose the right case-trimming tool for your needs.
Case Trimming Basics
Trimming the cartridge case to the proper length is a crucial step in case preparation that should not be overlooked or underestimated. The cartridge case or the rifle can be damaged, or even worse you get badly injured. In most instances cases should be trimmed after firing and sizing. Trimming new brass is necessary for a lot of wildcats and can be beneficial in some instances, but by and large, trimming new brass is not necessary for most situations (unless you are neck-turning). Cases should be trimmed after you have sized the case, because the expander ball on the decapping pin can (and will) stretch the neck. Those of us who neck size should get into the habit of trimming after sizing as well. This is a good rule of thumb to go by, and hopefully it will keep you safe during the reloading and shooting process.
There are so many case trimmers out there that work, deciding which one is right for you can be confusing. Even though I have trimmed thousands of cases, using about every method possible, I can’t answer the question of what case trimmer is right for you because of all the variables that may be involved. I can, however shed some light on the subject.
The two most popular designs of trimmers either index (1) off the base or the head of the case, (2) off the shoulder or datum line of the case. There are pros and cons to each and it all depends on what you are willing to live with.
Indexing off the Base (Case Head)
Let’s talk about the first one I have listed, indexing off the base, or the head of the case. The pros to this method are that you can achieve a very accurate over all length and that is after all, what it is all about. The cons to this method are that you can get some variation doing it this way. Let me explain, the base is not always square to the body or can be damaged during firing especially if it is fired through a military style rifle with a very aggressive ejector. These cases should be discarded, but sometimes they can be overlooked. This condition can lead to an over all length that is incorrect. The case head being out of square will be corrected upon firing, however that case will wind up being shorter than the rest of your cases, possibly creating a difference in the neck tension on the bullet. The more you can do to eliminate variables in your reloads the better off you are going to be. This method can also be very slow, and if the user gets careless the result will be a inconsistent over all length.
Indexing off the Shoulder (Datum Line)
The second method I mentioned, trimming off the shoulder or the datum line of the case, has its pros as well. I have found this to be the quickest of the methods and very accurate as well. After the case has been sized through the die the dimensions (particularly the headspace) of the cases are usually very uniform and exact, this allows the case to be trimmed by indexing off the shoulder. This method can be done very quickly, by hand, or by powering either the case, or the trimmer. You also don’t have to worry about the case heads being out of square with the body using this method. Generally the trimming time is cut in half, and this leads to greater focus on the job, without becoming careless. [Editor’s Note: The World’s Finest Trimmer (WFT) is one power device that indexes off the shoulder datum. It works fast and is very precise. The updated WFT 2 Model and WFT Big Boy feature interchangeable trim chambers to work with multiple cartridge types.]
Summary
The choice is yours to make. I hope that this was some help to you, whether you are looking for your first trimmer or looking to replace the trimmer you have. Just remember to always put safety first and accuracy second, and you will start making little bug holes in no time.
Story Tip by EdLongrange. User Submissions are welcome.
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Giraud Tool has a new case trimmer/chamferer that works with a power drill (or other power source). Giraud’s patent-pending Tri Way Case Trimmer is a self-contained unit powered by your drill or motor. Using a sharp carbide blade it will trim your cases to length, deburr, and cut both inside and outside chamfers — all in one pass. That’s pretty impressive for a $90 tool that fits in the palm of your hand.
Close-up of the Tri Way cutter with clear plastic chip guard removed.
Product Features
1. Fully adjustable for cartridge length (and depth of chamfer).
2. Tool includes carbide blade that cuts a 15° inside case mouth chamfer and 45° outside chamfer.
3. Case holder supported by sealed ball bearing raceway.
4. Tool includes removable, transparent plastic chip guard.
5. Tool can work in any orientation (vertical, horizontal, or any angle).
The Giraud Tri Way Trimmer is designed to be powered by a portable hand drill, drill press, or other dedicated rotating power source. The tool indexes off the shoulder of your cases, but the blade adjusts so that cartridge overall length (COAL) can be controlled with precision. Constructed out of 6061-T6 aluminum and 303 stainless steel, the Tri Way tool should last a lifetime. Note: This tool is not universal. The Tri Way is dedicated to a single cartridge and “related” cartridges with similar body dimensions. Thus you need a specific tool for each cartridge family. For example, the .308 Win tool will also trim .243 Win, .260 Rem, and 7mm-08.
Cartridge Sizes Available for Giraud Tri Way Trimmer:
.223 Remington (Also trims .17 Remington, .204 Ruger, .222 Remington, .222 Remington Magnum)
7.62 x 39mm (Russian)
.300 Blackout (Also trims .17 Rem Fireball, .221 Fireball)
.308 Winchester (Also trims .243 Winchester, .260 Remington, 7mm-08)
.30-06 Springfield (Also trims .25-06, .270 Winchester, .280 Remington)
.300 Winchester Mag (Also trims .264 Winchester Magnum, 7mm Remington Magnum)
Product Tip from EdLongrange. We welcome reader submissions.
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The folks at PMA Tool, makers of arbor presses, neck-turning tools, and other case-prep tools, offer some good advice about case trimming on the PMA Tool Blog. Here we reprint a PMA blog post that explains case trimming basics and helps you choose the right case-trimming tool for your needs.
Case Trimming Basics
Trimming the cartridge case to the proper length is a crucial step in case preparation that should not be overlooked or underestimated. The cartridge case or the rifle can be damaged, or even worse you get badly injured. In most instances cases should be trimmed after firing and sizing. Trimming new brass is necessary for a lot of wildcats and can be beneficial in some instances, but by and large, trimming new brass is not necessary for most situations (unless you are neck-turning). Cases should be trimmed after you have sized the case, because the expander ball on the decapping pin can (and will) stretch the neck. Those of us who neck size should get into the habit of trimming after sizing as well. This is a good rule of thumb to go by, and hopefully it will keep you safe during the reloading and shooting process.
There are so many case trimmers out there that work, deciding which one is right for you can be confusing. Even though I have trimmed thousands of cases, using about every method possible, I can’t answer the question of what case trimmer is right for you because of all the variables that may be involved. I can, however shed some light on the subject.
The two most popular designs of trimmers either index (1) off the base or the head of the case, (2) off the shoulder or datum line of the case. There are pros and cons to each and it all depends on what you are willing to live with.
Indexing off the Base (Case Head)
Let’s talk about the first one I have listed, indexing off the base, or the head of the case. The pros to this method are that you can achieve a very accurate over all length and that is after all, what it is all about. The cons to this method are that you can get some variation doing it this way. Let me explain, the base is not always square to the body or can be damaged during firing especially if it is fired through a military style rifle with a very aggressive ejector. These cases should be discarded, but sometimes they can be overlooked. This condition can lead to an over all length that is incorrect. The case head being out of square will be corrected upon firing, however that case will wind up being shorter than the rest of your cases, possibly creating a difference in the neck tension on the bullet. The more you can do to eliminate variables in your reloads the better off you are going to be. This method can also be very slow, and if the user gets careless the result will be a inconsistent over all length.
Indexing off the Shoulder (Datum Line)
The second method I mentioned, trimming off the shoulder or the datum line of the case, has its pros as well. I have found this to be the quickest of the methods and very accurate as well. After the case has been sized through the die the dimensions (particularly the headspace) of the cases are usually very uniform and exact, this allows the case to be trimmed by indexing off the shoulder. This method can be done very quickly, by hand, or by powering either the case, or the trimmer. You also don’t have to worry about the case heads being out of square with the body using this method. Generally the trimming time is cut in half, and this leads to greater focus on the job, without becoming careless. [Editor’s Note: The World’s Finest Trimmer (WFT) is one power device that indexes off the shoulder datum. It works fast and is very precise. The new WFT 2 Model with interchangeable trim chambers works with multiple cartridge types.]
Summary
The choice is yours to make. I hope that this was some help to you, whether you are looking for your first trimmer or looking to replace the trimmer you have. Just remember to always put safety first and accuracy second, and you will start making little bug holes in no time.
Story Tip by EdLongrange. User Submissions are welcome.
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Little Crow Gunworks has updated its popular “World’s Finest Trimmer” (aka WFT). The new WFT 2 version is more versatile — it can now easily change from one cartridge family type to another. That makes the $69.95 product an even better value. Trimming works the same way as before — just push the cartridge case into the trimmer and cut depth is pre-set. When ordering the WFT 2, choose a trim chamber for your particular cartridge family (such as .308, 7mm-08, .243 Win). You can trim multiple cartridge types (with one trim chamber) by ordering the largest chamber in the family you plan to trim. To trim cartridges from a different family, simply order (and install) a different chamber insert.
The WFT 2’s designers explain: “The two main improvements are the ability to trim up to 45 caliber and interchange trim chambers. The WFT 2 has a half-inch shaft and requires a half-inch chuck to drive it. The feature most customers asked for was the ability to interchange trim chambers. After many prototypes (and much testing) the solution came from our friend, Jim Lambert. Instead of press-fitting the trim chambers, as on our original WFT, the trim chambers on our WFT 2 feature a slight slip-fit-in bearing with a groove cut for an O-ring which creates a press fit.”
How to Change Trim Chambers
Changing out trim chambers is accomplished by removing the cutter and pushing out the trim chamber with the knock-out dowel that is provided with the WFT 2. To install the trim chamber, set the trim chamber on a flat surface and steadily push the housing onto the trim chamber. To set cut depth (COAL trim length) place a ‘master case’ in the trim chamber and slide the cutter up to the case mouth. The tighten the set screws.
Product Tip from EdLongrange. We welcome reader submissions
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We had a chance to try out the new power case trimmer head from Little Crow Gunworks. Dubbed the “World’s Finest Trimmer” (WFT) by its inventor, Dale Hegstrom, this device proved fast, precise, and easy to use. When compared to a Hornady Lock ‘N Load hand-crank trimmer, the WFT processed cases twice as fast, and delivered a more uniform cut length with our test brass.
The WFT features a steel shell-holder, aluminum body, and steel drive shank. You can chuck it into any electric drill or power device that can handle the 3/8″ shank. Unlike most case trimming tools, the WFT indexes off the shoulder datum. This permits you to trim cases very quickly, without fiddling around with rim-grabbing collets, or shell-holders. Watch the videos to see the WFT in action.
WFT is Fast and User-Friendly
Mark LaFevers, our tester, was easily able to trim five (5) cases in under 30 seconds. It took quite a bit longer to trim five cases with the Hornady trimmer he used for comparison. Mark noted that, after just a 20 or so manually-trimmed cases, his arm would start to fatigue. By contrast, he could effortlessly trim 100 or more cases with the WFT. For older folks with a bit of arthritis, the WFT makes life easier. Mark observed that the WFT produces a “nice, square, clean cut”, while offering a “very fast cycle rate”. He tells us, “once you get the hang of it, you probably can trim your brass two, if not three times as fast.”
Mark really liked the WFT tool, and a WFT will be replacing his hand trimmer for big jobs. One downside is that, currently, the WFT is cartridge specific — you normally need to have a different tool for each cartridge type you trim. And there are no swappable inserts allowing you to trim different cartridge types with the same tool. However some WFT versions WILL trim different cartridge types within the same “family”, such as .270 Win and .30-06.*
Hi-Rez Video Shows “Trim-Off” Challenge between WFT and Hornady Trimmer
You should definitely watch the five-minute video below. Mark trims five cases with the WFT, and then five more with the Hornady tool. He times the operation of each device and then measures the trimmed cases. The total variation (in length) of the WFT-trimmed cases was .001. With the Hornady tool, there was a much larger spread: .007″ (seven thousandths). Mark cautioned: “Normally the Hornady tool does a bit better than this — the variance won’t be so large. But getting better results (with the Hornady) might require trimming, measuring, then trimming again. In the video I was trying to move pretty quickly and the measurements were all taken after the initial trim. Possibly, if I slowed down when using the Hornady trimmer, the OAL measurements would have been more consistent. But that just further reinforces the point that the WFT is faster.”
NOTE: If you have a fast connection, we suggest you select 720p (HiRez) and expand to full screen.
In the video below, WFT creator Dale Hegstrom demos his device and shows how quickly it can trim a large quantity of brass. Note how the WFT is attached to a common rechargeable power drill.
“World’s Finest Trimmer” Costs $69.95
The Little Crow Gunworks “World’s Finest Trimmer is available for $69.95 from various vendors including Creedmoor Sports. WFTs index off the shoulder, not the base. The case fits tightly into a steel bearing which has been machined to a specific caliber. This decouples the stationary case from the spinning cutting blade and body, giving you a smooth, exact cut each time. While the WFT makes a nice, square cut, we do recommend chamfering inside and outside after the brass is trimmed to length.
*Most WFTs are cartridge specific. Available sizes include: .204 Ruger, .223 Rem, 22-250, 6mmBR, 6.5 Grendel, 6.5×47 Lapua, 6.5 Creedmoor, 6.5-284 (and 6mm-284), 6.8 SPC, 270 WSM, 7mm Rem Mag (and 300 Win Mag), .308 Win, 300 WSM, .338 Lapua Magnum. There is a ‘5 in 1′ WFT unit that will handle .17 Rem, .221 Fireball, .222, .223 Rem, and .222 Mag. The 6mmRem unit also works with .257 Roberts and 7×57 Mauser. The .30-06 WFT will trim .270 Win, .280 Rem, and .25-06 as well. And the WFT for Ultramags works with 7mm, 300, and .338 Ultramags.
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“World’s Finest Trimmer” Costs $69.95
