The 10mm Auto and .40 S&W share the same .400" bullet diameter, making them natural companions for the cast bullet caster. The 10mm is a high-pressure, high-velocity round demanding harder alloys; the .40 S&W runs at more moderate pressure and is easier to manage. Both are popular with semi-auto pistol shooters and benefit enormously from cast bullet economics given their relatively high round counts.
The .40 S&W was developed as a shortened 10mm that fits in 9mm-sized pistol frames. Both use .400"–.401" diameter bullets, so the same molds and sizing dies work for both. The difference is pressure: full-power 10mm loads run around 37,500 PSI while .40 S&W runs around 35,000 PSI. Both require harder alloys than 9mm or .45 ACP.
| Weight | Profile | Best Use |
|---|---|---|
| 155 grain | Truncated Cone, RNFP | High-velocity .40 S&W and 10mm loads |
| 165 grain | Flat Point, TC | Mid-weight all-purpose load |
| 175 grain | Semi-Wadcutter, FP | Competition 10mm, hunting |
| 180 grain | Round Nose, Flat Point | Standard weight, most versatile |
| 200 grain | Wide Flat Nose, SWC | Heavy 10mm hunting loads |
Both cartridges operate at pressures and velocities that demand harder alloys than most handgun cartridges:
10mm for hunting: The 10mm with a 200 grain hard-cast wide flat nose bullet at 1,200+ fps is a legitimate deer and hog hunting load. Hard-cast bullets at these velocities provide excellent penetration. Size carefully and use a quality hunting lube.
The M2R Automatic Casting Machine handles both calibers at production rates. Consistent hardness and sizing for demanding semi-auto cartridges.
View the M2R MachineYes — same diameter, same molds. Just load them to 10mm pressures and velocities with appropriate powder charges. Use a harder alloy when loading to full 10mm power.
Most barrels shoot best at .401". Some tight barrels prefer .400". Slug your barrel and size .001" over groove diameter as a starting point.