40/10 MM bullets

[Metalman1]

Being new to reloading, I got confused on which was what. When I search for 40 S&W I find Hornady .400 10mm 155gr HP/XTP or I find 40/10mm .401. I thought 40 S&W was .400 & 10mm was .401. Can a .401 bullet go into 40 S&W brass?
I should be getting my reloading gear mid April so I'm trying to have my stuff together.

 

[LiveLife]

Slug your barrel - http://www.youtube.com/watch?v=CR_WiL8Dkgw

For 40S&W with .400" groove diameter barrels, I usually load .400" diameter jacketed bullets and .401" sized lead bullets.

For .401" groove diameter barrels, .401" diameter jacketed bullets will provide better performance and you should use .402" sized lead bullets to reduce leading.

 

[GCBurner]

I think .400 is the standard for jacketed ammo, and .401 for cast lead or plated bullets. Both work in either 10mm or .40 S&W, and also in the old .38-40 Winchester cartridge.

 

[gamestalker]

Yes, jacketed .40 / 10mm bullets are .400", and lead / plated will vary. You need to slug your barrel if you intend to use anything but jacketed.

GS

 

[ljnowell]

I wouldnt bother slugging the barrel. I would buy some lead bullets in the standard .401 and try them. Then see if I needed to slug my barrel, etc. Never had to do it yet on a handgun, and I certainly reload for plenty of them.

 

[sevt_chevelle]

The 40sw and 10mm bullets ARE the same thing.

 

[Havok7416]

They are one and the same. I reload for 10mm and .40 out of the same box of bullets.