I have a 243AI reamer the neck dimsion is .2765 and my necked down LC brass with bullet seated the neck measures .2755.
Is this too small of a clearance should I turn them to maybe .003 different?
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I have a 243AI reamer the neck dimsion is .2765 and my necked down LC brass with bullet seated the neck measures .2755.
Is this too small of a clearance should I turn them to maybe .003 different?
I would go no less than.002 and would suggest more like.003-.004 I have ran them at .0015 but you have to be carefull and measure every case several times to make sure.
Steve
You need to turn the necks to a max of .2745" (preferably .274" - .273"). Your loaded ammunition has some crimp on it and you need at least .002" of clearance to release the bullet.
If you use that brass, you're gonna have to turn the necks. Maybe you could start at .003 clearance to begin you're load development, and if the pressures seem to come on too early, then turn the necks to .004 clearance.
If I can ask a silly question, why are you necking down LC brass, when Lapua makes wonderful brass ready to go in 243? All you have to do is load and fireform...
???
But what is the neck size on lupa 243 brass loaded?
I would agree that you would need to turn that brass,however my .243 with Norma or Winchester brass loads at .2715 or less.No turning necessary in your neck.I have a 243 AI coming with a .270 neck,so I'm turning .003 under that for a loaded round.
Okie,
Part of the issue is you're necking down 308 brass, which tends to make the necks thicker anyway.
Most of the Lapua brass I've seen (I use it in my 6.5x284 and 223 brass I form into 6 TCU brass) has necks running about .014 give or take .001. So .243+.014+.014=.271
Not to mention it's damn fine brass, very consistant, good primer pockets, consistent annealing in the neck shoulder junction area.
Lake City brass can be iffy, depending on what lot of brass you have. Some have been very good, some not so good. Is this "once fired", several times fired, or "range pickup" brass? You're going to all the trouble to make your own barrel, with a custom reamer, why cut corners on the brass? The 243 Win brass is cheaper than my 6.5x284 brass (if that's any consolation to you... ;D )