Two diameter GG bullets

[bruce moulds]

Richard,
I must confess to shooting pp bullets which feed into the bore.
because I don't have a pp chamber, I have evolved a dual diameter bullet which patches to groove diameter where it is in the case.
I do not size the case, just finger seating the bullet, and letting the bore set up alignment.
when I shot greasers, I used a file trim die backed off to minimally size, and then expanded the neck, just a little, with a baco 2 diameter expander.
the larger diameter allowed the bullet to start, and the smaller diameter was the same as the bullet.
with case springback this gave 0.001 neck tension.
it was enough tension to go hunting with.
I have done this with pp bullets as well, but for target shooting it is just unnecessary work and is probably less accurate than finger seating.
ammo runout is possibly not worth worrying too much about, as there are many things like holding and squeezing, using the optimum sighting element, and consistent barrel condition that can make a far greater difference.
I once tested some ammo in my fclass rifle with 0.008 runout fireforming cases against some with 0.0005 or less, and could not really tell the difference.
if you are going to chase runout, in the real world you need to neckturn the brass, and this is only useful in very specialized situations.
I do dial fclass ammo, but that has a far greater accuracy requirement than bptr. however only some rounds to check that nothing is awry.
when I started bpcr, long bore riding nosed greasers were de rigeur.
if I have learned one thing, it is that they bump into the rifling and can leave lead in your bore.
this happens less so when blowtubing except on the first shot.
an experimental bullet I had brooks make, with the bore ride having grease grooves, had no such problem.
keep safe,
bruce.