Case neck thickness (or thin-ness)


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ole farmerbuck
September 5, 2009, 09:19 PM
My two 223's arent grouping as good as they used to or as i think they should. I havent had the Savage very long but the Stevens has 4 or 500 rounds through it. Some of the brass has been loaded quit a few times and i Lee neck size mainly but the bullets seem like they seat easier than when i started out. Will well used cases cause groups to open up? I have no problem hitting p-dogs 150-250 yards but when i come home and shoot at my paper tatgets, i dont see why i 'm not missing the dogs. I've been using 26.0gr h335 with 40gr v-max bullets seated at 2.270. Any suggestions? Thanks

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Remo-99
September 5, 2009, 10:25 PM
Some of the brass has been loaded quit a few times and i Lee neck size mainly but the bullets seem like they seat easier than when i started out.

One thing you could try, is take a few of the cases with 'loose' neck tension and do a partial F/L size on them to see if this helps the groups.
By backing the F/L sizer off it can be adjusted to size the necks without bumping down the shoulders.

And if that helps to return neck tension to the older cases, it maybe that the collet necksizer die(if thats what you are using) may need some tweeking or even sanding down the mandrel making it slightly undersize, to give better tension on the bullets.

ole farmerbuck
September 5, 2009, 10:31 PM
I am using the collet die and have sanded the mandrel down to i think .218 or .219. I guess i can try the fl die as you suggested. I did notice a few split necks tonight so maybe i should just throw it away and break out a new batch.

flashhole
September 6, 2009, 09:05 AM
A couple of things -

1) have you cleaned your barrel really well lately with a good copper solvent? I was having similar issues with a couple of my guns and discovered my cleaning solvent was not formulated to remove copper. I picked up some good copper solvent and bingo ... got my lost accuracy back.

2) the brass will work harden after repeated firings, especially when running loads near the top end of the load range. Brittle brass will not size as well and will not provide the same neck tension. You could anneal the brass to soften it to see if that helps. Cracked necks is a good indicator your brass needs to be annealed, even then it may be too late to bring it back. You could also try measuring the ID/OD of the neck before and after sizing, check it against a "fresh" case and compare. The neck will compress against your mandrel and then spring back a bit when pressure is released. Embrittled brass won't size the same as good brass and this may be noticed by the feel of the bullet resistance when seating but I wouldn't use that to judge the maliability of the brass.

kelbro
September 6, 2009, 06:37 PM
I am using the collet die and have sanded the mandrel down to i think .218 or .219.

That's pretty small. Does it take a lot of force to seat your bullets? My mandrel is between .222 and .223 and it provides good neck tension.

ole farmerbuck
September 6, 2009, 08:25 PM
That's pretty small. Does it take a lot of force to seat your bullets? My mandrel is between .222 and .223 and it provides good neck tension



The cases spring back to .222 after necksizing. No. the bullets do not seat hard.

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