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11/5/2016 4:19:38 PM EDT
I recently bought some some fully processed Lake City 5.56 brass (LC10), the brass itself looks great, I measured case length, headspace and neck wall thickness, and it is very consistent. I compared it against factory loaded FGMM 77gr, FGMM 69gr, and Hornady Superperformance Match 75gr and it was basically identical.



The resized lake city necks are .242

Neck wall thickness is .013 (x2=.026)

Nosler CC 77gr @ .224




.242 - .026= .216  --------> .224 - .216 = .008 of neck tension




Is my math right?  Is .008 neck tension to much?  Am I gonna have to expand 1000 case mouths and then neck size them again?  




Input would be appreciated...







BTW for 75 -77gr bullets should I get buy some TAC, 8208XBR, or CF-223? Looking at the load manuals varget isn't getting the velocity the others are and the loads are compressed.  I'd like to buy 8lb jugs before Tuesday....
11/5/2016 4:53:06 PM EDT
[#1]
What tools are you using to measure those things? It's quite easy to miss measure small things like that.  

I would seat a bullet and measure neck thickness with bullet seated and compare to a neck thickness without bullet seated.  Might take some guess work out of it.  

What size is your expander ball?
11/5/2016 5:09:25 PM EDT
[#2]

Quote History
Quoted:


What tools are you using to measure those things? It's quite easy to miss measure small things like that.  



I would seat a bullet and measure neck thickness with bullet seated and compare to a neck thickness without bullet seated.  Might take some guess work out of it.  



What size is your expander ball?
View Quote
Using a mitutoyu caliper, the measurements are spot on for certain. the cases came fully processed for loading so my expander ball measurement is moot.
11/5/2016 10:59:13 PM EDT
[#3]
This is exactly why I never purchase "processed" brass.

If it were me, I would use them as-is since they're already sized, and then do them right on the next cycle (possibly annealing too).
11/5/2016 11:09:36 PM EDT
[#4]
Those numbers sound pretty standard and some dies I've seen will squeeze that neck even smaller. Get yourself some bushing dies and you can determine what neck size & tension you end up with. You can also ream or turn necks to adjust fit.
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