COP asked in SportsOutdoor RecreationHunting · 1 decade ago

Is a 45mm colt handgun a 45 caliber gun?

is 9mm pistol a 9 caliber gun

What is caliber?

and what is the milimenetrs all about

9 Answers

  • 1 decade ago
    Favorite Answer

    45mm is a hair over 2", it used to be that american created rounds were designated calibers due to the SAE units of measurement.

    Foriegn born rounds were given metric designations.

    Simply because thats what units of measure were used in the area.

    That is no longer true.

    It is true that a .357 magnum is about .357ths of an inch, BUT, calibre size is not always the actual size.

    .357 Magnums actually use a .358 bullet, while the .357 Sig uses a .355 bullet.

    The .38 Auto uses a .356 bullet, where the .38 Special uses a .358, and a .38 Smith and Wesson uses a .361 bullet.

    Generally the metric designations are the actual bullet size.

    Thumbs down jackass?

    -(H, he gave an ok answer except for the 10mm being a no-so popular. Little did he know, huh?)-

    And the 9x19 is widely implemented around the globe.

    EFERREL, As for same bullet size, this is only a small sampling however, the following- 7mmTCU, 7mm BR, 7-30 Waters, 7mm IHMSA, 7mm-08 Rem., 7x57 Mauser, .284 Winchester, 7x64 Brenneke, 7mm Express(.280 Rem), 7mm RSAUM, 7mm WSM, 7mm Weatherby Mag, 7mm Rem. Mag, 7mm STW, 7mm Ultramag, all feature the .284 bullet.

    Like the .40 S&W and 10mm use the same bullet.

    There are so many chambering that use the same bullet.

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  • 1 decade ago

    I will start with the 9mm:

    First: 9 millimeters = 0.354330709 inches

    9x19 - Luger/Parabellum - most used in the US

    9x21 - Mostly European firearms

    9x23 - Steyr

    9x23 - Winchester

    9mm Mauser

    9mm Winchester Magnum

    9mm Federal

    A 9mm pistol shoots a caliber of 9mm.

    Now for the .45....

    If you get a chance to see these actual cartridges side by side, you will also get a feel for the differing lengths and weights.

    .45 ACP

    .45 GAP

    .45 Colt/Long Colt

    There are a few more but these are the main ones available.

    The Long Colt is used mostly for Single Action revolvers.

    The .45 ACP is for most 1911A1's and most of the .45's out there EXCEPT for those chambered for the new .45 GAP (Glock Auto Pistol). They are NOT interchangeable.

    If you are using this for self-defense, I recommend buying the one that has the most ammo readily available wherever you will be traveling and that has the lower cost for practice ammo, if that is a factor.

    If you shoot a no-so-popular caliber, like 10mm, it may be tough to get ammo in some areas.

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  • 1 decade ago

    Millimeters and caliber are not interchangeable. Caliber is actually an imperial measurement based on an inch. When you say .45 caliber, it means that the bullet is (approximately) 45/100 of an inch across.

    A 9mm bullet is 9 millimeters across, which is roughly equivalent to .38 caliber.

    A 45mm round would be fired from a cannon, and roughly 4 inches across.

    The different measurements, mm vs. caliber, have no significance except that it indicates (sometimes) that a round was intended for international application. For example, the 5.56 NATO is roughly equivalent to the 223 Remington, but not exactly. It uses a mm designation to have significance in the international NATO community.


    45 mm is about 2 inches. bad math the first time.

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  • 1 decade ago

    No, as a 45 mm handgun would be a hand cannon. The bullet would be almost 2" in diameter. To be precise 1.773".

    .45 caliber refers to the approximate size of the bore.The caliber is measured either from the lands or grooves of the rifling. That accounts for the bullets being a different size than the caliber. There are only 2 calibers that are the exact same as the bullet size. .40 S & W, and .41 S & W magnum.

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  • H
    Lv 7
    1 decade ago

    It is a .45 Caliber (either Long Colt or Automatic-Colt-Pistol which is what 'acp' stands for).

    Millimeters are European designations for calibers. State-side calibers were expressed in American calibration until fairly recently when we also started using the millimeter designation.

    A quick and fairly accurate conversion is: To convert from millimeter to American calibration multiply times 4; a 9mm becomes a .36 caliber. To convert from American calibration to millimeter divide by 4; a .45 acp becomes an 11.2 something.


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  • 4 years ago

    In terms of the cartridge, it's a good cartridge. Plenty of stopping power. The cartridge itself is quite accurate up to 50 yards in a good gun. Don't know about it's penetration against body armor though. Against unarmored humans it's excellent and a proven performer since 1911. The downside is the gun. The M-1911 and M-1911A1 types firing this round are excellent proven performers and completely reliable. But, with the heavy recoil of the cartridge, even with the very heavy unloaded weight of 39 ounce of M-1911 type pistol, makes it very tough to handle for anyone who is not a fully trained shooter. The problem is the ergonomics of the pistol.. Designed before the importance of "making the gun fit the man" became evident, the M-1911 types are a poor fit to the hand. Along with the heavy recoil this breeds real FEAR of the pistol in anyone who is not completely and fully trained. This is not a joke or old wives's tale, Newer designed 45 caliber pistols since about the 1980's may be a better fit for the average shooter, but don't have the proven reliable performance record of the M-1911 types. "Also, the M-1911 type pistols only have a 7 round magazine capacity, 8 with a round in the chamber. In addition, later designed pistols, DA, etc. are safer to carry a round in the chamber. This is not because of mechanical failure of the pistol, it's because of repeated human error.* A better choice for the average shooter would be 9 mm with hollow points or one of the 40 S&W caliber pistols. *added paragraph"

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  • 1 decade ago

    .45 caliber refers to bore diameter in inches. The metric designation of the .45 acp cartridge is 11.25mm. I have seen this marked on many south american military pistols that are chambered for .45 ACP.

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  • Erika
    Lv 4
    3 years ago

    45mm Gun

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  • 1 decade ago

    Please follow the link and read the entire article.

    Thank you. :-)

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