I load 180gr bullets almost exclusively in 10mm and 40S&W, they work fine in both calibers.
I think you will get better Muzzle Energy (not to be confused with Power Factor) from a 165gr bullet when loading 40S&W. In general, with pistol calibers, you get more muzzle energy as you go lighter because velocity plays an outsized role in this calculation (unlike PF where bullet weight has equal weight with velocity). Muzzle energy is not the be all end all as bullet weight plays a roll in penetration and heavier is usually better in that capacity. These relationships are not linear and there is usually a sweet spot on the curve for any given loading.
As far as all that case head support nonsense with Glocks, if you load your rounds to published maximums, you will not have a problem in any bullet weight you might buy. I load .45 Super for my G21 using the stock barrel (one of the worst for lack of case head support in a current generation Glock) and have not even had a smile until well past Hodgdon maximums for Longshot.
My advice as far as bullet weight for your 40, get what is on sale and use powder manufacturer load data.
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Last edited by Bill Steele; 11-27-2012 at 7:58 AM..