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December 20th, 2018
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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November 19th, 2016
Trimming and chamfering brass are tasks hand-loaders grow to hate. Those chores are time-consuming and tiresome. Thankfully there are faster, better alternatives to manual trimming/chamfering. In this article, Forum member Erik Cortina shows how to use the Giraud tool which trims and chamfers in one operation. Erik has his own YouTube Channel dedicated to precision reloading and accurizing. Here we feature Erik’s video about the “mother of all brass trimmers”, the Giraud powered case trimmer. Erik says: “If you do volume reloading… this is the only trimmer to get. It not only trims to length but it also chamfers your case mouth inside and out.” In his video, Erik offers some very clever and useful tips that will help you get the most from your Giraud.
This is a manufacturer’s photo showing an older model.
The Giraud trimmer is very precise. When set up correctly, it can trim brass with amazing consistency. In the video, Erik trims five pieces of brass in 15 seconds (6:32 mark). He then measures all five with precision calipers (7:00-8:08). All lengths are exact within .0005 (half a thousandth). Erik notes that the Giraud trimmer indexes off the case shoulder. As long as you have fire-formed brass with consistent base-to-shoulder dimensions, you should get very consistent trim lengths.
The secret to the system is a 3-way cutting head. This cutter can be swapped in and out in a couple minutes with wrenches provided with the kit. Erik has three different heads; one each for 6.5mm, 7mm, and .30 caliber. The video shows how to adjust the cutting heads to match caliber diameter (and to get the desired amount of inside/outside chamfer).
To trim and chamfer cases, you simply insert them nose-first into the cartridge-specific case-holder. Erik offers a smart tip — He uses a die locking ring to position the cartridge holder (3:15). This can be locked in place. Erik says die locking rings work much better than the hex-nuts provided by Giraud (with the hex-nut, one must re-set cut length each time you change case-holders.)
The Giraud can be used in either horizontal or vertical modes. Erik prefers to have the trimmer aligned vertically, allowing him to push cases down on the trimmer head. But the trimming unit has twin sets of rubber feet, allowing horizontal or vertical orientation.
Improved Case-Holder Made with Chamber Reamer:
For his .284 Shehane, Erik had to create his own case-holder (Giraud does not make one for that wildcat cartridge). Erik used his chamber reamer. To his surprise, Erik found that the brass was easier to trim in the custom case holder (compared to the Giraud-made spring-loaded holders). With a perfect fit, trimming and case extraction went more smoothly and the process was easier on his hands. (See 9:00-10:00). Based on Erik’s experience, you may want to create your own custom case-holder.
Trim Bullet Meplats Also
With a special bullet-holder fitting and meplat cutter head, the Giraud power trimmer can be used to trim bullet meplats. Trimming meplats can help make the Ballistic Coefficents of a batch of bullets more consistent. Uniforming meplats is also often done as a first step in the process of “tipping” bullets to improve BC.
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April 16th, 2016
The Giraud power trimmer indexes off the shoulder of the case. It is costly, but offers high production rates, trimming to length and chamfering in one operation.
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.
The PMA Micro-Adjust Case Trimmer indexes case length off of the shoulder of a properly fire-formed and full-length re-sized case. We accomplish this through the use of interchangeable Delrin™ inserts which capture the shoulder and neck of the case. This insert is contained in a spring-loaded tool head that rides on a linear bearing. When the case is captured within the tool head the tool head rotates along with the case, the spring allows for the case to self-align squarely to the cutter and allows you to control the feed rate into the cutter.
— Indexes off shoulder for easy, consistent trim length
— Fully rotating head with bearing for smooth operation keeps cuts square
— Large, ergonomic design fits the hand well
— Sharp carbide cutter for quick, smooth cuts with minimal bur
— Cases captured in Delrin™ (completely non-marring material)
— Spring loaded head allows complete control of rate of feed.
Our trimmer can be used in three ways. The first method utilizes our PMA Tool caseholder drivers and your power screwdriver, drill, case lathe, drill press or lathe. Trimming via this method the case is spun and fed into the trimmer while it is held in your hand. In the second method, the trimmer’s adjustment knob is removed (after adjusting and locking the setting) and the cutting shaft is chucked in a drill, drill press or lathe. Using this method, the case itself is held by hand and fed into the cutter. We’ve found this to be the quickest method to trim.
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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November 3rd, 2015
Close-up of the Tri Way cutter with clear plastic chip guard removed.
Tired of trimming and chamfering your cartridge brass by hand? Giraud Tool may have a solution. Giraud, makers of rugged bench-mounted case prep machines, now offers 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 $98.00 tool that fits in the palm of your hand.
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 is rugged. 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 Rem, .204 Ruger, .222 Rem, .222 Rem 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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September 8th, 2015
“Once-fired, lot-number-traceable Lake City 7.62×51. This has been de-primed, pocket-swaged, small base body die’d, full-length sized, trimmed with a Gracey Trimmer, and tumbled. Now it’s shiny again. It’s like gourmet macaroni for shooters!” — Dennis Santiago
Our friend Dennis Santiago shoots a variety of disciplines, including Vintage Military Rifle. He burns through a lot of brass, some of it run through gas guns, so he often saves money by acquiring once-fired Lake City Arsenal brass. But that stuff is often pretty ugly when it arrives. For his “previously-owned” Lake City Brass, Dennis does a complete case prep operation and a thorough cleaning/tumbling operation. Special attention is paid to the primer pockets — they are swaged to remove the military crimp. The cases are trimmed and chamfered in one operation using a Gracey Powered Case Trimmer.
Dennis likes once-fired Lake City brass for some applications. The price is right, and with proper attention to detail during case prep, Lake City brass can shoot exceptionally well indeed. You may want to sort Lake City brass by weight. To remove the military crimp you have a variety of options — you can swage it out with a special tool like Dennis does, or you can ream out the crimp. For Wilson trimmer owners, Wilson makes a special Primer Pocket Reamer to remove military crimps. It works very well, as shown below:
 
Case Processing with the Gracey Trimmer
Designed by Doyle Gracey 30 years ago, the Gracey machine trims, deburs and chamfers in one operation, indexing off the case shoulder. The manufacturer claims the Gracey will process 20 cases per minute while holding .002″ tolerances on trim length. Two steel cutters are employed — one cutter trims the case to length and puts a chamfer on the inside of the case mouth. The second cutter removes the burr from the outside of the case-mouth. A 1/15 hp motor turns 1550 rpm. Interestingly, a clamped rubber hose serves as the “drive shaft” to turn the cutting head.
Trey Tuggle, writing in Shooting Sports USA, reviewed the Gracey Trimmer, giving it generally high marks, though it lacks some of the refinements of the more modern Giraud Trimmer:
“This model may have a piece of wood for a base, no on-off swith and a piece of bent sheet metial to contain brass shavings — but it does trim, debur and chamfer with great speed and accuracy at a nice price. The [Gracey] two-bladed cutter requires a little more patience to adjust than the one-piece cutter on the Giraud, but it gets the job done superbly. [The Gracey] does the job for less money, if you’re willing to tinker with the cutter blade adjustment.” Gracey machines are still available new from MatchPrep.com for $335.00 (or $235.00 without motor).
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May 4th, 2011
The May digital edition of Shooting Sports USA has a good article on Power Case Trimmers for rifle brass. Trey Tuggle reviews self-powered units from Giraud, Gracey, Hornady, and RCBS, plus a drill-mounted trimmer fitting from Little Crow Gunworks. Tuggle reviews the main features of each unit. Reading this article is recommended for any one in the market for a high-output, powered case prep machine. CLICK HERE to read story.
 State Champions Listed by Discipline
The May edition of Shooting Sports USA also dedicates six full pages to 2010’s State Champion shooters, listed discipline by discipline. The recognition give these many shooters is well-deserved. As you’ll find in every edition of Shooting Sports USA, there is a comprehensive calendar of NRA shooting competitions for a vast range of disciplines: Action Pistol, Air Pistol, Pistol Silhouette, Black Powder Target Rifle, Black Powder Silhouette, Lever Rifle Silhouette, Air Rifle, Smallbore Rifle, Smallbore Rifle Silhouette, High Power Rifle, High Power Silhouette, and more. You’ll find match listings for hundreds of shooting clubs around the country.
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