I just got off the phone with ruger and while it was tested with the .40S&W it causes MISFIRES and is not reliable RUGER DOES NOT RECOMEND USE OF 40S&W IN THE 10MM

Yes you can fire 40 S&W in it but after doing so it may be necessary to clean the ring of fouling that will occur just ahead of the case out of the cylinders before shooting 10mm's in it or they may not chamber.

Hi Gary, Yes you can shoot the 40 S&W also.

James remember the 40/10 mm s are not rimmed cartridges and normally headspace on the front lip. I know on my Blackhawk .45acp ruger machined a lip in the cylinder for it to headspace on not sure if they did that on the Redhawk 10mm or if they are relying on the moon clips to anchor the case (like a .38 rim)

The above.... But always, always check with the manufacturer for safety and warranty reasons. Ruger Telephone: 336-949-5200 / (Monday through Friday 6:00am - 5:00pm MST)

since it uses moon clips it would be possible but I would contact ruger and ask Telephone: 336-949-5200 (Monday through Friday 8:00am - 5:00pm ET)

Yes, the 40S&W is based off of the 10mm case (a shortened version).