Posted: 12/9/2005 12:09:54 PM EDT
| Ok may seem like a silly question...but when you compare a 9MM cartridge to a .38 Spl the .38 casing is much larger, so wouldn't it make sense that it would have a more powerful charge and be a more powerful round than the 9? So why are 9's more powerful? |
9mm has significantly more pressure and a larger powder charge, therefore making it faster and thus more powerful. The .38spl case is virtually empty. Somebody who has more knowledge than me will tell you why this is. Compare a 9mm and a .357 magnum running the same weight bullet and see what you get.  MJD
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| Most factory .38 Special ammo is downloaded by the manufacturers to avoid blowing up old revolvers designed for black powder cartidges much like the .44 Special and .45 Colt. In a modern gun designed to handle +P pressure you can easily match (and exceed) 9mm velocity out of a .38 Special, particularly with heavy bullets. |
Not really. .38 special was originally a black powder cartridge which is why the cartridge case itself is so long. When smokeless powder came out, as noted above, in order to prevent the smokeless .38 special loads from blowing up older revolvers chambered for .38, the cartridge was loaded with enough smokeless powder to equal the black powder charge. So, it wasn't really an "underachieving" round, the charge was comperable to the prior black powder load. +P ammo is just upping the charge to something that better represents the cartridge can do +P+ is a .357 load hiding in a .38 special cartridge... |
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The 38 Special was never loaded with black powder. Introduced in 1902 as the 38 Smith & Wesson Special as an improvement to the 38 Long Colt. It was introduced in conjunction with their Military and Police revolver. Colt introduced their named version in 1909. Eventually the name became simply, 38 Special. Pressures are held down to protect the many turn of the century firearms chambered for this round. But even a "modern" revolver that is not specifically noted for +P or +P+ use should not be loaded with that type of ammo. |
Correct, the .38 SP (like the .44 SP) was introduced as a smokeless round (though there probably was a BP loading as well, just like the .44SP had). The longer case length was mostly to prevent it from being chambered in older, weaker .38 chambered revolvers. Case capacity is a releatively small part of a cartridges power. In the old days of one propellant (black powder), the only variables were case capacity and bullet weight, and larger case meant more powder and more velocity with a given weight bullet. In the era of modern smokeless powders, it's really more about the pressure rating of the cartridge. You really can't just shove as much of whatever powder you want into a cartridge and make a more powerful round. The .357 Magnum is a more powerful round than the .38SP not because of a larger case capacity, but because it is loaded to higher pressures- either through different powders or more of the same powder- still well short of filling the case. The longer case on the .357Mag is again, mostly to stop you from loading it into a .38 chambered gun not rated to handle the pressure and recoil of the .357. The 9mm is (I believe) loaded to higher pressures than the .38, thus the higher perormance. Theoretically, the .38 could be loaded much hotter than the 9mm (due to it's larger case capacity), though not without exceeding the maximum pressure rating. I've seen some companies claim to be able to load the .38SP to near .357Mag levels without exceeding the .38SP+P pressure level, though I'm a little skeptical of the claims that it's no harder on the guns than firing .38SP+P. This post still falls well short of explaining it all perfectly, and someone may well take the time to expand on this in regards to my over simplification/ shortcomming regarding my pressure rating explanation. |
To expand on the above, SAAMI spec on .38 Special is 17,000 PSI, and 20,000 PSI for .38 Special +P. .357Mag and 9mm are both loaded to 35,000 PSI. 9mm +P is 38,500 PSI. 9mm +P+ has no SAAMI spec, and pressures vary by ammo company, so use with great caution. All else being equal, higher pressure equals higher velocity. Since velocity is one of the main components in calculating energy and momentum, higher velocity rounds (again, all else being equal) will produce more energy and more momentum. They will also produce more recoil. |
| Guys thanks for all the replies, I think I'm beginning to understand a little of this...so let me see if I have this right? Although you could fill a .38 spl cartridge with more powder than a 9mm, 9mm's are loaded hotter because the 9MM pistols are rated to handle a more powerful cartridge? |
9mm weapons are designed to handle higher PRESSURE loads. Higher pressure = more velocity and power, all else being equal. Firearms are built to certain standards, and one of the most important is the chamber pressure of the round. In the U.S. SAAMI establishes these operating pressure standards. All weapons chambered for a certain round are designed to withstand the operating chamber pressure for that round. A .38 Special guns are designed to safely fire a steady diet of rounds with 17,000 PSI (20,000 if rated for +P) chamber pressures. 9mm guns are rated to fire a steady diet of rounds that produce 35,000 PSI of chamber pressure (38,500 if +P rated). So, if neither gun is rated for +P, the 9mm will operate at about twice the chamber pressure of the .38 Special. There are probably well over a million guns chambered in .38 Special that cannot withstand more than 17,000 PSI chamber pressure. Factory loaded .38 Special rounds that take advantage of the large case capacity would be a huge liability issue for the maker of such ammo. These high pressure rounds would literally blow up guns which are perfectly safe when using the correct pressure loading. |
Yes, basically. There aren't many powders you could use to fill the .38 SP case to max capacity with (other than black powder or BP substitue) that wouldn't damage a .38 chambered gun gun when fired from it. The 9mm can handle higher pressure than the .38, and so you can use more of the faster burning, higher-pressure powders in it than you can in a .38. Case capacity is on the .38 is around 25 grains, but I bthink most loads go between 3 and 10 grains of powder, depending on the powder used. |
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