Caliber vs. MM
How do you convert caliber to mm? and vice versa.
Thanks,
Bob
Robert L. Ford
Thanks,
Bob
Robert L. Ford
0
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mm divided by 25.4 = caliber
caliber times 25.4 = mm
This is actually only approximate, because stated millimeters and calibers are often only approximate.
For instance, 30 caliber is 7.62 mm, but 30 caliber bullets are actually .308.0 -
Not so easy.
MM to inches is 25.4mm to 1". Caliber is normally thought to be decimal of inches. However, many of the calibers such as ".38 special" measure .356-.357" and a 9mm measures .355" instead of .354".
I'm quite sure some of the bullet experts here can give you a better explanation, just wanted to give you the metric conversion.
(I have to look in the books to make sure of diameter)0 -
Caliber is simply a unit of measurement of the diameter of the bullet using inches. .45 caliber means .45 inches wide. On the other hand, mm is the metric system measurement. 9mm means 9 milimeters wide. To convert use 1 inch = 25mm. 0 -
1 mm = (for all intents and purposes) .0395". In the case of a 9 mm
9 x .0395" = .3555" (close to the .356" of the 9mm).
Is this the conversion that you were looking for? Sometimes the rules of caliber vs diameter and gauge don't make a lot of sense....
Hope this helps.0 -
quote:Originally posted by hslaterpryce
1 mm = (for all intents and purposes) .0395". In the case of a 9 mm
9 x .0395" = .3555" (close to the .356" of the 9mm).
Is this the conversion that you were looking for? Sometimes the rules of caliber vs diameter and gauge don't make a lot of sense....
Hope this helps.
Robert L. Ford0 -
Dont feel like the lone ranger here...I still have trouble with this one. 7.62 = 30 cal. in most applications that is. I just bought a Swiss K31. That shoots 7.55 x 55 ammo. Going by the numbers, that should be small than the 7.62. But it is considered a .308. (Isnt that bigger than 30 cal?) I'm so confused. 0 -
Hello to add another worm to the bag .some countries use the bore diameter and some use the distance to the bottom of the grooves. Reloading manuals give you correct bullet size. also cartdridges of the world is good ref. quote:"PRAISE THE HARDBALL GUN" 0 -
Part of the problem is whether the measurement is of the bore or bullet (groove) diameter- for example, a .303 Brit & a .308 Win; the Brit is larger because the measurement is of the bore whereas the Win is a measurement of the groove. Add to this a conversion from metric; throw in the case length, grains of black powder capacity, grains of bullet weight, year of design, company that designed it, some guy the company liked, the velocity of a particular load, and God knows what else, & I can see the cause for confusion. It's why in Hunter Ed we advise the students to make sure the cartridge designation on the barrel matches EXACTLY the cartridge head stamp. 0 -
victory38,
I work with metrics every day.
Caliber is inches and of course mm is a metric unit. There are hundreds of unit converters on the internet that are freeware. Download one and go to "linear" or "length" then enter the dimension you want to convert. Very easy to use.
The only trick is knowing if the the caliber name is the true bullet diameter, e.g., 7.62mm = .308 inch or 30 caliber, 7.62x39mm = approx. .311 inch, 45 caliber = .451 or .452 inch, ad nausea.
Barnes in Cartridges of the World has a pretty good explaination of all of this and it is still very confusing.
Regards,
Heavy[:)]
Very confusing.0 -
as mentioned b4 1mm = appx .0395556 per my verizon phones calculator
SUBMARINE SAILOR,TRUCK DRIVER,RUSTY WALLACE FAN AND AS EVERYONE SO OFTEN POINTS OUT PISS POOR TYPIST e-mail alisonandwalt@charter.net0
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