[vsse]

Which is better in terms of power, accuracy, and lightness?

[Dave R]

They are pretty close. The .40 is only 1mm larger in diameter...

The .40 is slightly more powerful. The 9mm is slightly lighter, but the pistols for each probably weigh pretty close, with a few exceptions like the Kel-Tec P-11, which is lighter than anything available in .40, I believe. Then again, are the polymer-framed Kahrs available in .40?

Accuracy is pretty similar, too. That will depend more on the pistol than the cartridge.

[HSMITH]

Since we are in the handloading forum the 40 can be loaded to drastically higher power levels than the 9mm can with safe pressures. Factory 40 ammo is midrange and 9mm tends to be fairly stout closing the gap there but when I load both there is no comparison. I am talking over 200lb/ft of energy difference.

[mete]

On 4 legged things like woodchucks I find the 40 significantly better than the 9mm, in fact I can't really see any real difference between the 40 and 45acp. Most guns that are made in 9mm are also now made in 40 also.

[Black Snowman]

New pressure sensing equipment has changed load data a bit in recent years. According to the 2003 Hodgdon reloading annual the old 9mm data was actually quite conservitive. You might look into more modern loading manuals to get the most from a 9mm, but the extra case capacity and heavier bullets of the .40 tend to make it superior in most situations.

Lots of qualifying words in there ;)

[Clark]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

The brass, powder, and lead that 9mm and 40sw cartridge are made from are equal, so the power potential of the two should be proportional to their size.

In practice, the 40sw pistols may have a feed ramp that cuts into the chamber .235" but the case web is only .180" leaving .055" of thin unsupported case wall. Meanwhile many 9mm pistols have feed ramps .190" with case webs .160" thick leaving only .030" of thin case wall unsupported.

What does it all mean?
Most 9mms can be loaded to a higher power than most 40sw pistols.


What about 40sw pistol barrels with good case support?
They can have so much power that the recoil will do harm to your shooting hand.



TIG welded G22 and P32s for better chamber support
http://www.thehighroad.org/attachment.php?s=&postid=191655



finished G22, rechambered and new feed ramp for case support to the case web
http://www.thehighroad.org/attachment.php?s=&postid=245376

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