I've been reloading for 9mm and 44 magnum for years. Not until I started working with my Marlin 1894 44 Mag did I pay much attention to the expander powder funnel diameter of my Dillon 550 die sets. I started to size my COWW+2% bullets to .434 and load them up. When the finished rounds started looking like a snake which just ate a pig it finally dawned on me to check the size of the expander stem size. It was .426! Yikes! Pulled a few bullets and they were being sized down in the cases after bullet seating and crimping. I sent a note to Lathesmith and he suggested a new expander insert that was .431 diameter. Got it, works great, bullets aren't sized down in the reloading process and they shoot great. Next up was the 9mm. I have a P365, a P239, and a P226 pistol and they all measure .357. I size my 9mm bullets to .358. The only 9mm barrel I have which slugs .355 is a Barsto replacement barrel for my P226. I size those to .356. So I miked the 9mm expander die and it measured .350! Yikes! I was stuffing .358 bullets into a case expanded to .350. I ordered a new .355 expander from Lathesmith a couple of days ago to deal with this problem. This may be common knowledge for many but I was really surprised that the 9mm expander was only .350. Great for jacketed but not so much for .358 sized bullets.