[Hoodat]

I have a question for anyone who can help. I have a 10-mm handgun. I have not been able to find ammo for it locally for quite some time now. I am about to purchase some online, but I am not sure what to get. What is more important? Bullet weight or muzzle velocity? And does anyone have any preference to any particular brand? Does it make any difference what type of practice rounds I use? And finally, can I use .40-cal ammo instead? Several people have told me I can, but mathematically, .40-in is bigger than 10-mm.

Thanks in advance.

[txnativegop]

YOU CANNOT USE .40 S&w IN A 10MM. the .40 is a shortened form of the 10mm and would be dangerous in a semi-auto chambered for the 10mm.

Buy whatever is most accurate from your firearm. IMHO.

[Charles Martel]

If you’re talking about a Glock 20, I believe you can buy a drop-in conversion barrel for .40 S&W. There is lots of online info about that conversion. What exactly do you have?

[snuffy smiff]

No, they are both shoot the same diameter bullet. The 10mm just has a longer case in order to hold more powder. Whether you can safely shoot the shorter cartridge in your gun is something you’d best ask a gunsmith.
FWIW, the FBI gave up on the 10mm during testing because it was too stout and tended to go thru perps(and most everything else) instead of lodging inside the body where it does more damage. The designers then cut the case down and didn’t have anything better to call it than .40S&W.
Best bet for ammo would be to learn to reload(provided the components don’t go thru the roof!!) and start ‘rollin’ yer own’ ammunition.

[READINABLUESTATE]

No .40 cant be used in a 10mm. If you do and can get the pin to hit the primer.......Boom! (not in a good way) reload them....180gr JHP