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The “World’s Finest Trimmer”
Trimming cases with a manual trimmer is both time consuming and tedious. The necessary tools are an added expense and another item that needs to be attached to the workbench. Why bother? The answer is a simple one: consistent loads need a consistent length.
There are two main points of concern when it comes to cases with significant variations in over-all length. Overly long necks may actually work their way into the leade, crimping the bullet into place and blocking case neck expansion. The result is erratic pressures, high standard deviations, and eventually blown primers on loads that otherwise would be well within SAAMI pressures. The second issue is that bullets cannot be consistently crimped if they do not have uniform neck lengths.
A bullet is seated to the same depth within the cartridge by contact between the seater die and the bullet body. The roll crimp, however, is set by the case’s neck length and where it contacts the crimping portion of the die. Longer necks get more crimp, and because the bullet is be seated to the same depth each time, the crimp will be higher on the cannelure. The inverse is true of shorter necks. Cartridges with different neck lengths will have different neck tensions after the crimping process, which will negatively affect accuracy.
So, if you care about safe and accurate loads for your rifles, case trimming is a necessity. If you don’t want to spend a portion of your life turning a small crank on an expensive little lathe trimming a cartridge every few minutes: Go buy A World’s Finest Trimmer from Little Crow Gunworks. Brother, it is the best gadget going for people that need to trim a lot of cases accurately and quickly. It is also reasonably priced. Inventor Dale Hegstrom’s little tool is like moving from a washing board to a Maytag. God bless him for saving us from the drudgery of case trimming.
Hegstrom built his tool around an end mill that can be chucked into an electric drill. A precision-cut guide that indexes off the case shoulder and supports the upper case body holds the case steady during cutting. Moving the sealed bearing and trimmer body up or down the end mill sets the length of cut. Once the desired cut length is set, two set screws lock the trimmer into position. It is a beautiful idea.
Using sized brass (this is important because the system datum’s off a consistent point on the shoulder, much like a rifle headspaces) the case is pushed into the guide up against mill’s cutting surface. It is easy to feel when the cut has been completed, and the hard index off the shoulder makes over-trimming virtually impossible. Once the cut is completed, a quick quarter turn to knock off any burr that has formed will complete the process. I did more than five hundred .223 Remington cases in less than an hour while watching a movie on my IPOD. The only downside was that it made my thumb hurt after a while, but it was nowhere near the discomfort I would have had with my rotary trimmer.
Now, on to brass tacks. How accurately does it cut? The answer is pretty amazing. I picked twenty cases at random and measured them using a good set of calipers. The most extreme difference I found was one case that measured .0025” longer than the others. A closer examination showed a burr was killing the measurement. The other 19 cases were within .001” of each other. Amazing accuracy when the speed of each cut is considered, and quite a bit better than my rotary tool.
By design, the World’s Finest Trimmer works within cartridge families. I liked the .223 Rem. trimmer so much I bought their .308 model as well, which will also trim my wife’s .243 Winchester and my daughter’s .260 Remington. The $75 asking price seems like a steal considering its speed and the added cost of three new trimming mandrels. Usually cost and quality go hand in hand but in this instance, the WFT seems undervalued. It is very well made and ridiculously useful.
You can contact Little Crow Gunworks at http://www.littlecrowgunworks.com/wft.html or find it for sale on Amazon. If you do volume reloading, you need this tool.