Larger Case But Less Velocity? (9mm vs. .38)

S

SlackO

New member
What's up with this? Why are all of the numbers for the 9mm @ 1100 fps +/- but the .38 spl only gets 900+/-? The case of the .38 spl is MUCH larger than the 9mm (luger/parabellum) but seem to be loaded much lighter...

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Anarchism: The radical notion that I am the sole authority when it comes to deciding what's best for me.
 
Most 38 special loads have a cup of 16,000 or less where as the 9mm is in the 33,000 or less .That has to do with the pressure in the case in other words you can load the smaller case up to a higher cup than the 38 special
 
The .38 spl evolved from the earlier .38 cal rounds, such as the .38 long and the .38 S&W. The case length of each successive round was increased. This was to prevent people from blowing their guns up from loading a new more powerful round into an older, weaker handgun.
Also, the ealier .38's from the 1800's used black power, which takes up more space than smokeless powders.

Chris Nemeth
 
The more recent cartridge extensions have been the .357 Magnum, an extended .38 Special, and the .357 Maximum, an extended .357 Magnum. The latter never caught on, though.

The .38 Special can be loaded hot, as in the +P+ loads which are supposed to be used only in .357 Magnum revolvers. Of course, the +P+ loads were developed for police PC. There was a lot of opposition to the police using .357 Magnum (excessive power, don't hurt the BG, etc.), so the .38 +P+ allows near .357 velocity while the Police PR guy can say they are using the old standard .38 Special.

Of course, that all went out the window when most departments went to the 9mm and .40.

Jim
 
Slacko,
It has to do with bullet weight and available powder capacity.
It is not at all hard for the .38 to match 9mm velocities as long as the same bullet weight is used. I get 1200 fps out of my BHP with 115 gr. bullets. I can also get 1250 out of a 4" .38 with 110 grain bullets. The difference is moot. Just because a case is bigger does not necessarily mean that you are obligated to put more powder in it. I use 8.5 gr. of Blue Dot under a 180 gr. bullet in my .40's but I also use 8.5 gr. of Blue Dot under a 115 gr. bullet in a 9mm. The difference is the amount of room in the case that the gas has to expand in vs. the weight of the bullet and force required to propel it out of the case.
In an extreme comparison, if you put 50 gr. of a given powder in a .30-30 case under a 150 gr bullet and the same amount of poder in a piece of 2" pipe with an 8 ounce potato stuck in it, which one do you think will go faster? Such is the case with most comparisons between 9mm and .38. Many times, they use 115 gr bullets in the 9mm and 140 or 158 gr bullets in the .38.

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DJ
desertscout@hotmail.com

"The very atmosphere of firearms anywhere and everywhere restrains evil interference -- they deserve a place of honor with all that is good."
--George Washington
 
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