Please explain the difference between .38 and .380 (vanity)

2/16/03 | self

[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.

[TXnMA]

The head diameter of the .380 is smaller than the 9mmP,

The (rimless, in both cases) head of the .380/9mmKurtz/9mm short/9X17 case is definitely smaller than that of the full-sized 9mmParabellum/9X19 case.

In fact, here is a useful bit of trivia: the base of the .380 pistol round and the .223/5.56mm rifle round are basically the same -- they use the same baseplate for reloading.

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...? ;-}

[Double Tap]

A shotguns "gauge" is determined by how many lead balls the diameter of the bore it takes to make a pound in weight. A 12 gauge shotgun means that 12 balls of lead that will fit in that barrel diameter will weigh a pound. 10 gauge means 10 balls of lead.

The exception is the .410, which is the bore diameter.

[Myrddin]

I prefer corn cob with a tablespoon of Dillon brass polish. Walnut is good for a first pass on grade 3 brass purchased from Midway or similar. A finishing pass with corn cob makes it ready for use.

I've noticed that nickel plated .357 Magnum brass is most likely to split at the case mouth. Plain brass is less likely to work harden and split. For .454 Casull, the StarLine brass is best. I've tried reloading Hornady brass. It fire forms to the cylinder and must be tapped out with a wood dowel. The StarLine brass falls free with a tap of the extractor. That's important if you have need of a reload in a hurry. Think bear.

[BenR2]

ping

[Myrddin]

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...? ;-}

The volume of 748 powder pushing that puny 55 gr spitzer makes up for it :-) 3150 fps makes for some serious muzzle velocity.

[Gary Seven]

Yes they did switch back. The .357 was first marketed in 1935. It used high velocity to compensate for being a lighter and smaller bullet than a .45. At the time the FBI was looking for a handgun bullet that could penetrate automobile sheet metal and still stop a human inside. The .45, if it penetrated a car door at all (remember car metal was much thicker then), lost too much energy doing so to efficiently stop the person inside the vehicle. For many years ballisticians argued over the merits of each (light fast small bullet vs big heavy slow bullet. I don't think many criminals cared much about being shot with either caliber...

Since my need for a handgun is for personal protection only, not duty use, and is for last resort, and having owned both calibers, I love my .45. If I'm doin' the shootin', I want the .45. If I'm gettin' shot at, I'd rather it be by a .380... There are stories of .380's bouncing off a perp's skull...not a good caliber to rely on for personal defense. 9mm is the smallest I'll accept. IMHO

[Dave S]

firing a .380 in a 9mmP chamber could cause a case rupture and damage to the gun and your hand.

Oops. I wont be doing that then. My hand thanks you.

[Oschisms]

Thanks for your explainations. Needless to say, I am not a firearms owner. :) Living in NYC'll do that to you.

[templar]

...Federal Hydra-Shok hollow points for"self-defense".

Hydra-shok's are excellent. The lighter calibers (.380, etc.) seem to come apart too easily for winter use though. But for summertime, the .380 Hydra-shok is my choice for my .380 Walther PP.

BTW, the wadcutter is always considered a target round, but it is far superior to a regular round nose for defensive use. Just for fun sometine, try shooting some gelatine and you'll be impressed by the difference.

[uglybiker]

I have a 380 Llama - Looks like a scaled down .45 and was the RAF pilots sidearm in WWII.

I just picked up a Llama. How do you like yours?

[rudy45]

Let's see if I can complicate the matter:

The gauge of a shotgun is the reciprocal of the weight (in ounces) of the shot used in that gun (?)

[rudy45]

For many years ballisticians argued over the merits of each (light fast small bullet vs big heavy slow bullet.

I remember from physics that F=ma**2 (force = mass times the second power of acceleration). Therefore, if I want more stopping power, I would want double the speed (which would QUADRUPLE the stopping power) rather than double the mass (which only DOUBLES the stopping power)--I think (?)

[Chemist_Geek]

The gauge of a shotgun is the reciprocal of the weight (in ounces) of the shot used in that gun (?)

Not quite. We're talking about a single lead ball. Even the largest shot, 0 buck, has more than one pellet per shell. Slug shells aren't spherical projectiles.

The density of lead, I just looked up in the Alfa Aesar catalogue, is 11.34 g/cm³. The volume of a sphere is (4/3)*pi*(d/2)³. And, um, a pound is 0.454 kg. So, a 12 gauge shotgun will fit a ball which is 1/12th of a pound or 37.8 g, which based on the density given above has a volume of 3.34 cm³, or a diameter of 1.85 cm. (If I did the calculations right, it's only 8:30 AM here.)

[absalom01]

The math looks good, but you didn't convert to inches -- divide by 2.54 and you get .755 inches, which is spot on, even with two unit conversions.

This is true for all guages except the .410, which is not a guage, but a caliber. Given the way this thread is going, I'm sure someone can fill us in on the historical reasons for this -- I've heard plenty of lore, but not much in the way of fact on this point.

What a bunch of geeks!

[Shooter 2.5]

Since I was scrounging brass from the range, the stuff was always filthy. At the time, I only concerned myself with getting the dirt off and cleaning it so there wasn't an residue. I found some loaded .45 Colt that was horrible looking in my stash and I couldn't remember why I had let things go like that.

It changed my way of thinking. From now on, my finished product is going to look like something I can be proud of.

[thescourged1]

Great thread, people!

I'm not happy until I learn something new every day.

[Servant of the Nine]

"Explain about the Sig .357 autoloader. Because I don't understand why they did that."

It's quite simple, it's marketing. Sig wanted a cartridge that could captitalize on the reputation of the venerable .357 mag. It's not a .357 and it's not a magnum but it is a good cartridge.

They did that because a lot of police departments are enamoured of the .357 magnum revolver cartridge. The .357 SIG is an automatic pistol cartridge that exactly duplicates the balistics of the .357 magnum police load with 115 grain hollowpoint bullet. It helps them to sell police depts a 14 shot sig semiauto to replace a 6 round Smith & Wesson revolver.

So9

[B4Ranch]

Good try. LOL