10mm bullets in 40 cal cases [Archive] - Glock Talk


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11-01-2012, 17:55
Ok just starting to reload. Bought a rock chucker SS. I may have ordered the wrong bullets. I thought I ordered 40 cal. Anyway they sent me 10mm .400 diam 155 gr bullets. I have not bought brass yet. I will be shooting a Glock 23 40 cal. My question is can I load these 10mm bullets in 40 cal cases and shoot in my glock. Or do I need to send these 10mm back and order something else.
Thanks guys

11-01-2012, 17:58
the 10mm and 40sw use the same bullet. The 40 was made by cutting a 10 down and going to a small pistol primer.

11-01-2012, 18:09
Does that mean I can load the 10mm bullets in 40 cases and they will be fine in my G23?

11-01-2012, 18:13
They'll be fine.

11-01-2012, 18:39
Before you delve any further into reloading get several reloading books and read them all cover to cover several times.:shocked:

11-01-2012, 18:47
You are good to go. Same bullet.

11-01-2012, 18:50
Going to sit down in a little while and read the reloading book that came with the press.
Thanks for the help guys

11-01-2012, 18:54
Get a copy of "The ABCs of reloading" a great reference book for all reloaders.

michael e
11-01-2012, 18:55
Get a real book, the data sheets that come with the dies are not the best .

11-01-2012, 19:18

As everyone has said, both 40s&w and 10mm use the same diameter bullets (0.400"). Usually you only see > 180gr in 10mm only (such as 200gr, etc.)...

Good luck,


Steve Koski
11-01-2012, 19:44
Load those 10mm bullets backwards, they're more deadly that way.

Brian Lee
11-02-2012, 12:22
The only difference I can think of is that there are a few limited expansion hollow point bullets on the market that I suspect might not expand correctly at the lower velocity of .40 caliber. But there's no diameter difference.

11-02-2012, 20:27
Before you delve any further into reloading get several reloading books and read them all cover to cover several times.:shocked:http://www.glocktalk.com/forums/images/smilies/thumbs%20up.gif, and for the record you can not shorten 10mm casings and load them to 40S&W specs.

11-05-2012, 09:03
Don't load them!! Loading a 10mm bullet in a .40 S&W mortally embarrasses them, and they won't come out of the chamber!!


11-05-2012, 09:19
I am confused. Imagine that. I don't want to fire a 10mm bullet and case from my 40. I want to load a 10mm bullet into a 40 case and fire from my 40. Can I do that and be ok They are 155 gr.

11-05-2012, 09:58
You desperately need to loom at the cartridge specs in your reloading manual.

1. 10mm and .40 Cal bullets are the same.
2. A .40 Cal barrel will not accept a 10mm round. Its too long. Never mind the gun probably won't either.

11-05-2012, 18:41
You're getting some fun poked at you in case you haven't figured that out yet. A "40 caliber" (.400) is the SAE measurment of 4/10 of an inch. The metric conversion of this is 10mm.

11-05-2012, 18:43
And I agree with the others, read much more than you have already before you attempt to load any ammo.

11-05-2012, 18:58
It is the same thing as a .38spl/.357 magnum they both use the same diameter projectiles. a case lenght and power level is the difference. the chambers on the less powerful rounds are shorter so the longer, more powerful rounds don't get fired in a gun not capable of handling the higher pressure loads.

You really need to get some research and reading under your belt before you start loading live ammo.

11-05-2012, 19:33
Back on point. I spent time reading and doing some math. Set up the dies by making some rounds without powder or primers. Hardest part was figuring out how to set the seat and crimp die correctly. After more reading and youtube videos I got it figured out.
Thanks guys