17 Remington feeds, fire ball, has to have the extractor in a different position than normal...what they did on rifles for that cartridge.
#4 contour from lilja is a good one, just slightly heavier than factory.
If you can find a gunsmith that has a good 17 Reamer, zero freebore to a .020-.030 freebore you will be in the money. Magic happened when I turned the necks on my 17 rem as varying brass thickiness opened groups a little. With turn neck, zero freebore chamber on a shilen, lilja barrel, expect sub 1/4" groups with quality bullets like Berger 25g Match or other custom bullets.
Have you ever seen a 1/4" 17 caliber group? DANG...that is a small group!
17 Mach 4 groups with turn neck, zero freebore chambers are simply idiot proof to deal with working up loads with 25g Bergers.
A 9 Twist in a 17 Remington shooting a 30g Bullet would be a coyote killing machine for sure.
