I'm using RCBS competition dies for my 308. The expander ball has got some scratches on it. Polishing it makes it smaller. I'm about done with it anyway.
My bullets are measuring 0.3085 my Sinclair expander for my neck Turner is 0.3070. the mandrel on the neck Turner is 0.3065. it's a tight sliding fit when I neck turn. Got to use imperial die wax or the cases will seize on the mandrel. That means the inside neck diameter is almost exactly 0.3065 and roundness error might be causing a slight interference.
So what I have effectively, including brass spring back is 0.002 in interference fit on the diameter neck to bullet.
Most people call that 2 thousandths of neck tension. That's a different topic for a different day.
So 0.002 is a middle ground, or slightly low neck tension. When seating bullets in new Lapua brass the seating Force seems adequate for a heavy bolt gun. But I'd like to try a mandrel that's 0.0005 to 0.001 smaller for a little bit more grip on the bullet.
Does anyone know a source of mandrels that will fit the Sinclair neck expander that comes with their nt2000 neck turning tools? I've been all over their website and didn't find it yet. I'd like to get a mandrell that fits the tools I already have.
The last thing I need is another another tool that does just one thing!
Any suggestions who might have it?
My bullets are measuring 0.3085 my Sinclair expander for my neck Turner is 0.3070. the mandrel on the neck Turner is 0.3065. it's a tight sliding fit when I neck turn. Got to use imperial die wax or the cases will seize on the mandrel. That means the inside neck diameter is almost exactly 0.3065 and roundness error might be causing a slight interference.
So what I have effectively, including brass spring back is 0.002 in interference fit on the diameter neck to bullet.
Most people call that 2 thousandths of neck tension. That's a different topic for a different day.
So 0.002 is a middle ground, or slightly low neck tension. When seating bullets in new Lapua brass the seating Force seems adequate for a heavy bolt gun. But I'd like to try a mandrel that's 0.0005 to 0.001 smaller for a little bit more grip on the bullet.
Does anyone know a source of mandrels that will fit the Sinclair neck expander that comes with their nt2000 neck turning tools? I've been all over their website and didn't find it yet. I'd like to get a mandrell that fits the tools I already have.
The last thing I need is another another tool that does just one thing!
Any suggestions who might have it?
