Thread: Brass FL Sizing Trouble

Just be careful if FLSing so there is still bolt resistance. I used to always do it that way (could just feel resistance at the final point of closure) but now aim for 1 thou clearance ie no bolt resistance when closing. If you have resistance ensure you always lube the locking lugs as you risk galling. At any rate, reading your first post no resistance was your aim.

I have just measured some new Lapua 6.5 SM brass using my Hornady comparator with the C bush. I got a measurement which is close to your 1.762 but is probably of no relevance due to maybe small differences between my comparator and yours. I was hoping to give you a factory unfired number which is what I would work to with second hand brass.

My new unturned Lapua brass runs at 14 thou neck wall thickness. It could however differ slightly lot to lot, but at 14 thou I would expect to use a 0.290 bush which would give approx. half thou spring back for 1.5 thou neck tension. For hunting ammo I would go 0.289.

Another thing I have now gone away from is using bushing dies with expander stems remove. I now always FLS and reduce the neck to a couple of thou below required and then use an expander mandrel to get the required neck tension.