elkaholic
Well-Known Member
Wow, that's quite a bit of variation for Lapua! If there is only a couple that are .007", I would probably leave those alone and use them as foulers, etc. If you can, try to keep them all at .006" or less, but uniform.
Neck turning?? Hurt accuracy?
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elkaholic
Well-Known Member
Mikecr
Well-Known Member
It's a bad assumption about Lapua being so good. As far as thickness variance, it changes with cartridge & lots. I have seen the best in Norma (223rem), pretty good in Lapua (223rem), and the worst in one lot of Lapua (6br). On average, for thickness variance, it appears to me that Lapua is on par with Winchester reloading brass, which I see as ~1/2thou variance.
Something important if your goal is low runout.
Neck turning only addresses necks, while a lot of runout comes from the entire length of cases, that builds with sizing.
So if you want lowest runout, and I'm talking about over many reload cycles, you need to carefully measure neck thickness and fully cull those with ANY variance.
I do this with all brass brands that I've used, including Lapua.
Now if your cartridge is of best reloading design, your chamber is tight, and your sizing is minimal, you can get away with thickness variance & unturned necks & still make straight ammo. One trick here is to run an expander mandrel through necks before seating bullets. That's a mandrel, and not a button. I call it 'pre-seating'.
This drives some thickness variance outward away from seating bullet bearing, so bullets seat straighter. It also sets the correct interference fit for bullet seating to same OAL/CBTO.
If your neck clearance is already ~5thou, don't bother turning. Pre-seat instead.
Something important if your goal is low runout.
Neck turning only addresses necks, while a lot of runout comes from the entire length of cases, that builds with sizing.
So if you want lowest runout, and I'm talking about over many reload cycles, you need to carefully measure neck thickness and fully cull those with ANY variance.
I do this with all brass brands that I've used, including Lapua.
Now if your cartridge is of best reloading design, your chamber is tight, and your sizing is minimal, you can get away with thickness variance & unturned necks & still make straight ammo. One trick here is to run an expander mandrel through necks before seating bullets. That's a mandrel, and not a button. I call it 'pre-seating'.
This drives some thickness variance outward away from seating bullet bearing, so bullets seat straighter. It also sets the correct interference fit for bullet seating to same OAL/CBTO.
If your neck clearance is already ~5thou, don't bother turning. Pre-seat instead.
I'd never neck turned until last year. I sized some 308 to 7mm-08 and was worried about neck thickness so got a neck turner for RCBS case trimmer. ran some different cases through it and loaded some '06 but never fired them. Could never get a load to shoot very well in that gun. Fianlly shot it on Sunday and it grouped fine. Had some 7mmRM loaded with necks turned, 61-65 grains of rl22 with 2 different 160-162g bullets and every shot went into the exact same group. Brand new gun and first shooting. I'm impressed to say the least, never had a rifle fire all loads in same spot.
