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Posted: 1/24/2013 7:59:00 AM EDT
| I am setting up my gracey trimmer with the giraud blade and i am having problems with case length for .223 which will be used in ar's. I am trying to set up the trim length right now and 1 case will be 1.751, another will be 1.755 and they all range +.001 to +.005 without making any adjustments on the trimmer. This is with lake city brass and resized on dillon full length dies. Any help would be appreciated. |
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There could be any number of causes.
1. These trimmers index off of the shoulder, not the case head. Case length is measured from the case head. This difference could be one cause, all by itself. 2. If your cases are resized to different amounts of shoulder set back, this could cause the variation. 3. How hard you push the case into the case holder/cutter head will affect trim length. 4. Spinning the case while in contact with the cutter head will affect trimmed length. There are other possible causes, too. These just came quickly to mind. If a +/-2 mil variation is not acceptable to you, then you should get a Wilson trimmer. It trims cases with less than 1 mil total variation. It is the most accurate trimmer available. Why do you need such accurately trimmed cases? Trimming is done to keep the cases under the stated maximum length. It is done for safety. Small variations, such as your +/- 2 mils, is totally acceptable as long as the maximum case length is under the given limit. |
| Thanks for the response and those were the main things that came to mind that could affect the length. I didn't think people were getting that much variation with the gracey trimmer with giraud blade but maybe they are. If that is acceptable variations for lengths, then I am fine with it as these will be plinking rounds for my ar's. this is my first time setting everything up and just wanted to be sure the length was ok, thanks for your help. |
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Quoted:
Don't try to hit the length right at 1.75 inches, you'll drive yourself crazy. Shoot for 1.753 or 1.754. These trimmers that index off the shoulder are also sensitive to the force applied to the case. Try to us a uniform push every time. Thanks, that is much easier to do then what I was trying lol |
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Quoted:
Thanks for the response and those were the main things that came to mind that could affect the length. I didn't think people were getting that much variation with the gracey trimmer with giraud blade but maybe they are. If that is acceptable variations for lengths, then I am fine with it as these will be plinking rounds for my ar's. this is my first time setting everything up and just wanted to be sure the length was ok, thanks for your help. The giraud and gracie may be more accurate than you are. If you are making a trim measurement using the case head face as one of the measurement surfaces, then that face roughness could interject error from case to case. For bottle neck cases, IIRC, the giruad spaces off the case shoulder which is correct. How accurate your shoulders are set in your sizing die, and the degree of irregularity in your case head faces can add up to cause error in the 1.751 measurement. |
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