Posted on 02/16/2003 7:49:45 PM PST by rudy45
I had always believed that the caliber of a gun was the inside diameter of the barrel. Assuming I am correct (am I?) then shouldn't .38 and .380 be "close"? If I remember from high school math, the latter simply implies a greater degree of precision. IOW, a .38 caliber really could be anything from .376 to .384, while .380 caliber has smaller variance--.3796 to .3804?
However, the attendant at a local range said that .38 refers to revolvers while .380 refers to pistols (?)
Thanks.
After a good night's sleep, I have a fresh perspective on your experience. Recall that I mentioned the .45 ACP headspaces on the case mouth. That is because it is a straight-walled case. The case mouth diameter when crimped is the same as the case head diameter. That is NOT the case with 9mm brass. The 9mm and .380 ACP are tapered. The case mouth is smaller than the case head. The consequence is that your .380 was probably dangling into the firing chamber, hanging by the case head. A proper fit between the brass cartridge case and firing chamber provides support for the brass on all surfaces. The .380 ACP in the 9mm chamber would have no support beyond the case head. Upon insertion, the weight of the bullet at the case mouth would be slightly nose down i.e. the cartridge would not be colinear with the bore of the barrel. The bolt face could exert pressure on the lower edge of the case head to straighten that misalignment. Under this condition, the firing pin would have access to the primer. Firing that round would raise the possibility of pressure ballooning of the unsupported brass casing between the case head and case mouth. A burst or split may also occur. The consequence might be a jammed piece of brass or a failed extraction. It is something you definitely want to avoid.
The .380 also has a smaller bullet weight and powder charge. Even if you successfully fire the round, the mass of the slide and recoil spring is tuned to the mass of a 9mm bullet and powder charge. It is unlikely that enough energy will be transferred to the slide to properly cycle the blow back action of the 9mm pistol.
If memory serves, at one time American pistol calibers were referred, for some reason, to the outside cartridge caliber, rather than the inside bore of the barrel.
Hence, the actual bore of the .38 is .357; the .357 magnum is just a lengthened .38 catridge case, with more powder and chambers capable of withstanding the higher pressures of the more modern powders used in the .357; you can fire .38 cartridge inside a .357 cylinder, but not the reverse, for safety reasons. And since these are revolver cartridges, they are rimmed.
The .380 is just the American name for the 9mm Kurtz, or short, cartidge, which is shorter (9x17mm, I think?) than the standard 9x19mm NATO (or Parabellum, or Luger, etc.). Being a semi-auto cartridge, the .380 is rimless. I think (if memory serves) the actual bore for a 9mm is .351, so it is close to, but slightly less than, the bore of the .357/.38.
Yes, but the best pistol is still a rifle.
Search around. Best forum on the internet for 1911 related guns.
If I weighed 210 and stood 6'2", I'd carry a 1911 Colt or Colt Commander. Period.
/john
Heck yeah. I've never had a problem with my Walther, and it's much more comfy to carry concealed than any 1911 could be.
Remember, a .22 in the hand beats a .45 at home!
Most likely a .380 in a 9mm chamber would not fire at all. Most autoloader cartridges are rimless and headspace on the shoulder, in this case the leading edge of the case, so there would be too much slop in the fit for the firing pin to hit the primer unless you pointed it straight up! Even then a case rupture shouldn't harm a pistol built to withstand 50% greater chamber pressure but still not a good Idea.
I used to reload 9mm for my Browning Hi-Power using 80 gr. .380 bullets loaded to 1400 fps, it was quite spectacular.
You can reload the 9mm in a lighter practice bullet with less kick (great for the wife) and you can reload the .380 with a slightly heavier bullet.
10% heavier on the .380 and 10% lighter on the 9mm means you can use the same bullet. Powder loads, are a different story, however.
/john
I'm sitting here with a 9mm round (Winchester factory load) and a .380 round (PMC cheap commercial reload). I also have a micrometer. The .380 reads 0.368 at the base. The 9mm reads 0.3862.
I think the ejector on the wife's Sig held the .380 round in place even though it was 0.0182 inches smaller than the 9mm round.
/john
Yea, it's really great... just make sure not to stuff a .357SIG into the .40S&W barrel and vice-versa...
Force does not equl mass times acceleration squared, but rather just the mass times the acceleration (F=ma)
Not to worry, Rudy. I have a Taurus .357 mag and I shoot .38+Ps in it all the time. Also I have a college degree, but half this stuff is over my head, too!
In a rimless cartridge like the 380 ACP and the 9MM Luger the depth that the cartridge seats (also known as head space) into the chamber is set by the front rim of the cartridge. In a many rimmed cartridges like the 38 Special and 357 Magnum the head space is set by the base rim. That being the case, you can safely fire a 38 special in a 357 magnum because the case is shorter and is head spaced on the base. A 357 cartridge will not drop far enough into a 38 special because chamber isn’t deep enough to allow the longer case to fit. This was by design to keep the heavier loaded 357’s from firing in lighter framed guns.
If you were to drop a 9mm cartridge into a 380 Auto, the case would bottom out in the chamber and leave about a quarter inch sticking out of the chamber and the action would not close. On most guns if you were to drop a 380 Auto cartridge into a 9mm the case would drop too far into the chamber and the firing pin would not reach the primer. If by chance you could get either to fire you would likely have problems because of either an action that was not closed or too much movement of the case inside the chamber.
In both cases, as someone above mentioned, caliber sizes are mostly naming conventions. 38 Special and 357 mag both use a .357 caliber bullet. 380 ACP and 9MM both use a .355 caliber bullet.
It’s even more interesting to look at rifles. There are bunches of 30 caliber rifles that all shoot varying shapes and weights of bullets that are all .308
Thx,excellent review
“How does that make you M-16/AR-15 fans feel — to recognize that your rifle’s case diameter is the same as the relatively puny .380 pistol cartridge...? ;-}”
Considering that a 5.56 mm bullet has as much energy at 100 yards as a .45 ACP does at the muzzle, not too bad. Why?
No, a .380 is a 9mm short, 9mm Luger ammunition is too long to fit in the chamber. You can fire a .380 in a 9mm Luger but it likely won’t cycle reliably after the first shot because the magazine is not designed for the shorter ammunition. Longer 9mm cases will not chamber in a .380 and firing 9mm Luger ammunition in a .380 should not be attempted. 9mm ammunition in general is loaded with heavier bullet, the case holds more powder, and greater pressure is generated when the bullet is fired.
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