Welcome guest, is this your first visit? Create Account now to join.
  • Login:

Welcome to the NZ Hunting and Shooting Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.

DPT Black Watch


User Tag List

+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 21
Like Tree8Likes

Thread: Caliber names

  1. #1
    Member mattdw's Avatar
    Join Date
    Apr 2012
    Location
    South Canterbury
    Posts
    102

    Question Caliber names

    So, the .303 caliber is actually .311" in size. But the .308 caliber is actually .308" in size. However, .308 is also called "7.62 NATO" despite .308" being 7.8mm. Also, "7.62x39" (which may pre-date 7.62 NATO?) is actually .311". 7.62mm is 0.300".



    The .223 caliber is actually .224", or 5.68mm, but it's also called the "5.56 NATO". .224 and .220 are also .224", as is anything called ".22", but .222 (which used to be .222") is .223". 5.56mm is actually around .219", so who knows where that came from.



    The 6.5mm caliber is .264", despite 6.5mm being .255" (While the ".25" family clock in at .257".)

    7mm is actually .284" which is somewhere around 7.2mm, but maybe that's just lazy rounding.

    I'm aware that this is mostly a series of historical accidents and "near enoughs", but did nobody ever stop and think "this is getting a bit out of hand, perhaps we need to rethink our naming system"?
    PerazziSC3 likes this.

  2. #2
    Member
    Join Date
    Nov 2012
    Location
    BOP
    Posts
    17,587
    Now that's heavy! The .45 cal I size to .41 and the .577 I size to .571 and the .55 I use a .53 ball wrapped in onion paper, so it all started long long ago
    mattdw likes this.

  3. #3
    By Popular Demand gimp's Avatar
    Join Date
    Dec 2011
    Location
    The Big H
    Posts
    8,009
    7.62mm groove, 7.8mm land = .308.

    Etc.

    It's to do with land/groove diameters for most of these

  4. #4
    Member
    Join Date
    Nov 2012
    Location
    BOP
    Posts
    17,587
    And using lead as I do it bumps up and fits the bore

  5. #5
    308
    308 is offline
    Member 308's Avatar
    Join Date
    Dec 2012
    Location
    Wgtn
    Posts
    2,190
    Talk to women about clothes sizing - now there's a completely inconsistent nightmare
    Wirehunt and Maca49 like this.

  6. #6
    Member
    Join Date
    Jul 2012
    Location
    Galatea
    Posts
    1,099
    I thought most modern calibers came after the 30/06 named because it was 30cal designed in 1906... 30/06. The 308 was a shortened version of the 30/06 I cannot remeber how the 08 came into it but I thaught it was a measurement thing. Most names came from the designers/wildcatters looking for a catchy name and have little to do with exact bore size. This was my understanding which may be partly right or not at all. Wheres flintlock when you need him.

    Sent from my GT-I9300 using Tapatalk 2

  7. #7
    By Popular Demand gimp's Avatar
    Join Date
    Dec 2011
    Location
    The Big H
    Posts
    8,009
    .308" is the groove diameter, 7.82mm. .300 or 7.62mm is the land diameter.

  8. #8
    Member mattdw's Avatar
    Join Date
    Apr 2012
    Location
    South Canterbury
    Posts
    102
    So e.g. .223: 5.56mm = .219", .224" diameter = .005" groove depth.

    .308 vs .300 = .008" groove depth. (.303 vs .311 = also .008" groove depth? But it's named for the smaller not the larger.)

    6.5mm = .255", so .264 - .255 = .009" groove depth.

    And so on, I guess. So, interestingly, where there's a mm-united caliber name (5.56, 6.5, 7, 7.62), that usually seems to refer to the smaller dimension, and the corresponding imperial measure (.223, .284, .308) seems to refer to the outer dimension. Is that just accidental, or something the euros and americans do differently?

  9. #9
    Member
    Join Date
    Nov 2012
    Location
    BOP
    Posts
    17,587
    With the older rifles you need to slug the barrel to get the dimensions, an difficult to measure uneven number of rifling grooves. Older barrel can vary

  10. #10
    Terminator Products Kiwi Greg's Avatar
    Join Date
    Dec 2011
    Location
    Nelson
    Posts
    5,809
    Quote Originally Posted by Maca49 View Post
    With the older rifles you need to slug the barrel to get the dimensions, an difficult to measure uneven number of rifling grooves. Older barrel can vary
    Also on new ones that don't have the calibre/chamber designation engraved on the barrel......

  11. #11
    Member mattdw's Avatar
    Join Date
    Apr 2012
    Location
    South Canterbury
    Posts
    102
    Huh, interesting. It is something I like about guns (my day job is computers) is just how lo-fi the tech really is. Sure, my 25-06 may not be the "best" caliber, but hell, a 1906 cartridge design is still doing pretty well, that's quite something.

    My 6-year old laptop is obsolete, my 106-year old cartridge still has off-the-shelf ammo and rifles for it, and apart from the noise, barrel length, short barrel life, and poor projectile selection , competes reasonably well.

  12. #12
    Caretaker
    Join Date
    Dec 2011
    Location
    Hawkes Bay
    Posts
    6,509
    Quote Originally Posted by mattdw View Post
    Huh, interesting. It is something I like about guns (my day job is computers) is just how lo-fi the tech really is. Sure, my 25-06 may not be the "best" caliber, but hell, a 1906 cartridge design is still doing pretty well, that's quite something.

    My 6-year old laptop is obsolete, my 106-year old cartridge still has off-the-shelf ammo and rifles for it, and apart from the noise, barrel length, short barrel life, and poor projectile selection , competes reasonably well.
    117g ballistic tips or 115g vld projectiles would bring your 2506 right up there with the best of them
    A big fast bullet beats a little fast bullet every time

  13. #13
    Member Scouser's Avatar
    Join Date
    Dec 2012
    Location
    JAFA
    Posts
    4,510
    'my 106-year old cartridge still has off-the-shelf ammo and rifles for it, and apart from the noise, barrel length, short barrel life'


    Hi guys, excuse my ignorance, if im reading the above statement from mattdw correctly, does 25-06 cal 'burn barrels' quickly with factory ammo?....as i have one!
    While I might not be as good as I once was, Im as good once as I ever was!

    Rule 4: Identify your target beyond all doubt

  14. #14
    Member mattdw's Avatar
    Join Date
    Apr 2012
    Location
    South Canterbury
    Posts
    102
    Scouser, my understanding is, yes, relatively so. I'm running warm handloads, and can expect somewhere around a thousand rounds before accuracy starts to fade, I think. Factory ammo would presumably be a little better if it's not running as hot. (I could be wrong on this.)

  15. #15
    Terminator Products Kiwi Greg's Avatar
    Join Date
    Dec 2011
    Location
    Nelson
    Posts
    5,809
    Quote Originally Posted by Tussock View Post
    Its all relative. Depends on your definition of quickly. If you fire hundreds and thousands of rounds then yes. If you fire 20 a year then no.

    But yes, compared to other rounds they tear into barrels, as they are quite overbore. The barrel I took off my older Ruger 25-06 was visibly obliterated.
    The poo for free is suprising hard on barrels for a factory round especially if you use them for what they are best at, ventilating heaps of Goats in a hurry.....

 

 

Similar Threads

  1. next caliber help
    By longrange308 in forum Reloading and Ballistics
    Replies: 31
    Last Post: 25-10-2012, 10:15 PM
  2. Peta-names-sexiest-vegetarians
    By chux75 in forum Off topic
    Replies: 5
    Last Post: 02-07-2012, 10:56 PM
  3. Dog Names
    By cambo in forum Hunting Dogs
    Replies: 33
    Last Post: 21-06-2012, 12:52 PM
  4. Dog Names
    By cambo in forum Dogs
    Replies: 33
    Last Post: 21-06-2012, 12:52 PM
  5. Coloured Names
    By Tone in forum Off topic
    Replies: 21
    Last Post: 09-01-2012, 06:45 AM

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Welcome to NZ Hunting and Shooting Forums! We see you're new here, or arn't logged in. Create an account, and Login for full access including our FREE BUY and SELL section Register NOW!!