G’day Greysky,
I agree with 454PB, the seating depth effects pressure much more than diameter when using lead projectiles in small capacity cases, and whole heartedly endorse 454PB’s recommendation that you start out low and work back up when you change any of the critical parameters such as seating depth, bullet weight or powder type.
I have looked at the drawing of the projectile you mentioned on the R&C Bullet web site; I have used an identically shaped .357 projectile in my CZ and Glock 17. The only thing you might encounter, depending how deep the projectiles are seated and the dimensions of your sizing die, might be a bulge in the case at the base of the projectile.
A slight bulge is usually not a problem as long as the ammunition still feeds reliably; it is caused more by the way 9mm carbide sizing dies are made than a “one or two thou” increase in bullet diameter. I even went to the trouble of selecting a 9mm carbide sizing die (from my collection) with the longest carbide insert (Dillon if I remember correctly) and honing it until it sized the case only the required amount for correct bullet tension. The ammunition does not shoot any better, but it looks prettier; and 5000+ rounds over the past 6 months in practice and IPSC competitions without malfunction is an indication that it is not worse.
Paul
