Is it safe?

[DeanoBeanCounter]

Mods, move if you need to.
You can shoot 38SP out of a 357 Mag. You can shoot 44 SP out of a 44Mag. Is it safe to shoot 40S&W out of a 10MM?
Your thoughts?
Dean

[Tom W.]

Not a recommended practice unless it's a revolver designed to do so. It can be done, however.

[Calamity Jake]

38 SP thru 357 and 44 SP thru 44 mag, YES!!!

40 S&W thru 10 MM, NO as the round needs to head space on the case mouth.

[country gent]

38 spl 357mag 44spl and 44 mag all headspace on the rim of the case. While 40 S+W and 10mm ( also 45 gap and 45 acp) headspace from the case mouth. Firing 40 S+W in a 10mm auto may fire there will be misfires due to the extractor holding case back. In a revolver like Smiths 610 that uses half moon or full moon clips for extraction it can be done but its hard on the clips and the added bullet jump can be hard on accuracy.

[Texas by God]

It's totally safe to try, it may or may not work. Sometimes the extractor can hold the case against the breech face firm enough for the firing pin to ignite the primer. Sometimes it wont. It all depends on the gun. Navy Vet 1959 used to post here about firing 40 Smith & Wesson in his 10 mm. There's nothing inherently dangerous about it, it just might not work because of the headspace issue. I have successfully fired 380acp in a 9 mm Largo Astra 400. If it works, be sure and clean your gun afterwards!

Sent from my SAMSUNG-SM-G930A using Tapatalk

[Tom W.]

I watched Hickock 45 do it once... He didn't recommend it, however.