If you were to convert it what would 9mm be?


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hometheaterman
October 23, 2009, 06:45 PM
If you were to convert it would a 9mm bullet be a 38 caliber or what caliber?

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mljdeckard
October 23, 2009, 06:47 PM
.38 caliber is not .38 caliber.

The literal 9mm conversion is .355 or .356 of an inch.

http://en.wikipedia.org/wiki/9mm

rockit
October 23, 2009, 07:18 PM
And a 38 as in 38 special is .357, like a 357 magnum.

gym
October 23, 2009, 07:45 PM
38, 380, 357, 9mm. diameter wise pretty much the same. It's the amount and type of propellant that makes the difference. The 380 is called the 9mm kurtz in German, It is on the side of many German made guns, it's a short version of the 9mm cartridge. Just take off the zero and the 380 is a 38. Was that what you were asking?

JCisHe
October 23, 2009, 07:48 PM
Uhm, Gym, you are wrong friend. The bullet diameter is different. Read above.

Ringer
October 23, 2009, 07:53 PM
I think gym is spot on. He said "pretty much the same" not exactly the same. In terms of overall performance for comparison sake I can't think of a common cartridge much closer to 9mm than a .38.

CypherNinja
October 23, 2009, 07:59 PM
Don't forget those revolvers that can shoot all those calibers without swapping cylinders or barrels, either. :D

The two families, [9mm/.355(autos)] and [.357 (revolvers)], aren't exactly the same, but they're quite close.

CUTENAME
October 23, 2009, 09:21 PM
Just a Start:

Metric(mm) English/US Inch
5.40 mm .213
5.50 mm .217
5.56 mm .225
6.00 mm .236
6.35 mm .250
6.55 mm .258
7.00 mm .276
7.62 mm .300
7.65 mm .301
7.70 mm .303
7.92 mm .312
8.00 mm .315
8.40 mm .331
9.00 mm .354
9.50 mm .374
10.00 mm .394
10.50 mm .412
10.60 mm .417
11.00 mm .433
12.00 mm .472
12.50 mm .492
12.70 mm .500
13.00 mm .512
13.40 mm .528
14.40 mm .567
14.80 mm .583
15.25 mm .600
15.40 mm .606
16.40 mm .646
17.40 mm .685

ColeK
October 23, 2009, 09:27 PM
I wouldn't convert a 9mm, I would sale it. And buy another .38 Special, .357 Mag or .45 APC.

Isher
October 23, 2009, 09:39 PM
Cutename -

I've seen this argument go round a few times.

Actual bullet diameter tends to vary a few thousandths

From the black and white English/Metric conversion.

So whether you are talking mm or english,

The caliber is approximate to the actual math.

isher

gyvel
October 23, 2009, 09:42 PM
Here's a simple little trick for you that will give you approximate conversions from metric to "calibre."

One mm is approximately 4 "calibre" (a "calibre" is .01")

Just multiply the metric bullet designation by 4 and you will have a "close enough for government work" bullet diameter. For example, 9x4=36, so a 9mm bullet is approximately 36 calibre. (Actual is .355, but the number is rounded up.)

Conversely, by dividing a calibre designation by 4, you get an approximate metric designation, i.e. 40 cal. divided by 4 gives you 10 (i.e. 10mm.)

Unfortunately, because of disparities in naming some cartridges, primarily in the 19th century, dividing by 4 won't give you a true metric designation in every case. The classic case would be the 38 Special, which is actually a bit smaller than 36 calibre (.357"). Likewise, a 44 Special or Magnum is technically a little smaller than 43 calibre. (.429")

This trick isn't meant to give you exact measurements, but you will have a close enough approximation to get an idea of comparison.

Yoda
October 23, 2009, 10:17 PM
I've been told that the bullet diameter of old Russian "9mm" Makarov was slightly larger than the 9mm Parabellum. For this reason, it would be unwise for me to try to shoot "9mm" Makarov through my S&W Model 940, which is a 9mm revolver.

So I've been told by folks smarter than me.

- - -Yoda

MD_Willington
October 24, 2009, 01:20 AM
9x18, the bullet is actually 9.2mm uses .363" diameter bullet

Yosemite Sam
October 24, 2009, 04:49 AM
Here's how the math is done:

http://i60.photobucket.com/albums/h8/mrjickles/THR/9mmconversion.jpg


But I guess if we look at the actual bullet design, the real dimensions are different:

http://i60.photobucket.com/albums/h8/mrjickles/THR/9mmdiagram.jpg


It's just easier to say "9 millimeter" than "9.017 millimeter".

TEDDY
October 24, 2009, 09:31 AM
its not wise to figure to much and to much explanations.
europe cal. go by the hole size not the rifleing size.the bore is .303 but the bullet is .312.americans use the bullet size.
the 44CB uses 45 cal bullet.the 36 cal used 38 bullet.best I can discribe it.and then there are the other names.you really have to memorize the cal.

bubbaturbo
October 24, 2009, 09:50 AM
So to summarize, a 9mm is either .354 inches, .355 inches, .356 inches, approximately 36 caliber, or you can't tell because of the Europeans. :)

kanook
October 24, 2009, 10:24 AM
38, 380, 357, 9mm. diameter wise pretty much the same.I think gym is spot on. He said "pretty much the same" not exactly the same.If the OP is going to reload, then they are not even close.

9mm uses a .355 - .356 diameter

38 S&W uses a .360

38 special and 357 mag use a .357 - .358

Just think if the OP tried to push a .358 down a .355 bore. Or god forbid he get a box of .360

Some firearms will slug out different to get better results.

eye5600
October 24, 2009, 10:49 AM
Wikipedia is a great resource for this kind of question. There has been an on-going project to put up shooting information.

See: 9x19mm_Parabellum (http://en.wikipedia.org/wiki/9x19mm_Parabellum)

The magic number for converting from inches to/from metric is 25.4. There are 25.4 mm in one inch, so 9mm is 9/25.4= .3543 inches.

However, as noted above, you can not reliably tell the actual diameter of a bullet from the name of the cartridge. Some names are based on the bullet, some on the casing, some on pure marketing hype.

It looks to me that the diagram at the above link says that the bullet is 9.03mm or
9.03/25.4 = .3555 inches, while the text suggest than in the barrel, the lands = 8.82 mm, and the grooves = 9.02 mm.

armsmaster270
October 24, 2009, 02:16 PM
Kanook has the normally accepted data: 9mm -.355 jacketed, .356 lead/ 38/357mag -.357 jacketed and .358 lead however there were slight differences between S&W and Colt barrels. On another note the 357Sig round uses 9mm bullets.

MachIVshooter
October 24, 2009, 07:54 PM
its not wise to figure to much and to much explanations.
europe cal. go by the hole size not the rifleing size.the bore is .303 but the bullet is .312.americans use the bullet size.
the 44CB uses 45 cal bullet.the 36 cal used 38 bullet.best I can discribe it.and then there are the other names.you really have to memorize the cal.

There's so much wrong with this statement, I'm not even going to bother correcting. Just suffice it to say that one needs to know the correct nominal bullet diameter for the cartridge and firearm they are using.

Just think if the OP tried to push a .358 down a .355 bore. Or god forbid he get a box of .360

They'll go. Just compresses the bullet a bit. The bigger problem may be chambering the round; that extra .005" may cause the case mouth to be too large.

You have to remember just how small a thousandth of an inch is, how much force you're talking about, and how easy it is to swedge copper and lead. There have been cases of people firing .30 caliber rounds in .284 caliber rifles with no adverse effects beyond pierced primers, and you're talking .024" there.

I'm not advocating the use of incorrect diameter bullets, simply stating that a conventional lead or jacketed bullet a few thousandths over bore size is not going to leave the shooter an amputee.

Shadow 7D
October 25, 2009, 03:59 AM
BTW, which 9x18, I think that there are at least 4..

Dr-Science
October 25, 2009, 04:19 AM
http://www.google.com/search?hl=en&source=hp&q=9+mm+to+inches&btnG=Google+Search

gyvel
October 25, 2009, 08:26 AM
BTW, which 9x18, I think that there are at least 4..

Well, there's the 9x18 (9.3x18) Makarov, and the 9x18 Ultra, but what else?

Proinsias
October 25, 2009, 08:44 AM
9mm Police.

Blackbeard
October 25, 2009, 09:40 AM
Just think if the OP tried to push a .358 down a .355 bore. Or god forbid he get a box of .360

I don't think the OP meant to suggest firing different ammo through a 9mm gun. I think he meant to ask what 9mm is in English measurement.

dom1104
October 25, 2009, 05:36 PM
this..... is the longest thread with the most answers for the simplest question that really should never have been asked since a quick google search or any reloaders manual would have answered it.

WOW.

gyvel
October 31, 2009, 05:07 AM
9mm Police.

I think that is just another name for the 9x18 Ultra.

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