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> Neck-size Query
Neck-size Query
@ 10:40 pm (GMT) |
Andrew MurrayHi all,Having some difficulty with neck-sizing different brands of brass. One brand (Winchester) neck-sizes correctly. The other brand (Norma) appears to only be correctly sized near the case shoulder, or just above. Pertinent info: Norma brass was 7mm-08 Brass that was full length sized some time ago. It was "fire-formed" last weekend. In hindsight I believe this neck size issue was present also when loading after FL sizing but I have confirmed it now. The case shoulder is sized to approx 7.76mm (projectile is 7.82mm) However the very top of the neck is 7.9mm. This means the projectile doesn't bite until it is quite deep in the case. The Winchester brass is old, faithful, never fails. Neck sized always. The die is Lee Collet neck-sizer with the de-priming capper pin. The press is a Lee Classic. I've lowered the die in the press to bring the crimp in the die "higher" on the brass, but it doesn't appear to affect the outcome. Anyone experience something similar before? |
Replies
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@ 04:41 pm (GMT) |
Andrew MurrayRe: Neck-size QueryA response from Lee Precision below via email. I removed the contact details and names for privacy of the staff.Staff - 04/03/2025 3:21 pm Hi Andrew, it appears you might be seeing the current revision we have made to the collet neck sizing die and have been made that way since 2019. The current design and revision of the collet neck sizing die leaves the very end of the neck of the case unflared for a number of reasons. The first for easier and more concentric seating of the bullets. It also allows better consistency with accuracy due to that as well. Let me know if something different was occurring or if that was causing any chambering issues. https://support.leeprecision.net/en/knowledgebase/article/updated-collet-neck-sizing-dies https://support.leeprecision.net/en/knowledgebase/article/advantages-of-the-lee-precision-collet-neck-die ***** I don't find this reply actually addresses the concerns. My email to Lee was verbatim above. I read that perhaps the brass may have been work hardened and is springing back to the original dimensions, which may be affected somewhat by the above information. Very odd however given that I haven't yet annealed my Winchester brass and it sizes correctly. |
@ 06:26 am (GMT) |
Nathan FosterRe: Neck-size QueryHi Andrew, the explanation helps to some degree, though the email reply had a typo. It should read; the very end of the neck flared (not unflared).So you have two things going on here. The first is a change to the die design involving a flared case mouth which can be quite useful. But the problem you are experiencing is a slightly thick mandrel that is not allowing you to size down to the appropriate neck tension. Please follow the instructions for altering the mandrel as shown in your copy of my reloading book. Note that the brands of brass vary a great deal in neck thickness which makes it impossible for Lee to create an optimal diameter mandrel. Redding utilize bushings, leaving the end user to select an appropriate size. The Redding system is costly but optimal. Lee have tried their best to master the production of inexpensive equipment. In some instances, you may find that the importer keeps a stock of different sized mandrels. By the same token, an importer may simply stock replacement mandrels of the same size to replace damaged items. If you cannot obtain a smaller diameter replacement, it is up to you to alter the existing item accordingly. Small alterations / test sizing are the key. The goal is to obtain adequate neck tension without mucking up concentricity. OK, hope that helps a bit. |
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@ 01:50 pm (GMT) |
Andrew MurrayRe: Neck-size QueryCheers Nathan,I have also considered binning the cases. As mentioned the Winchester brass behaves as expected. I appreciate your advice of course but I'm not keen to make modifications until I've wrapped my head around it. I'm struggling to understand how the neck at the shoulder is sized properly but the mouth is way beyond the dimensions of the barrel. Perhaps there is something very obvious i am missing or have failed to grasp. I'll keep at it for the time being. |
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