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Joined: Nov 2009
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Campfire Ranger
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OP
Campfire Ranger
Joined: Nov 2009
Posts: 15,885 |
The other day, someone had a thread about a 8mm rifle. Having never heard of such, I googled up a conversion site and looked it up. Then as a fluke, I checked some others that I thought I knew. Such as 6mm = .244, nope = .236...... What about 6.8 = .277, wrong again = .268. One more try, 5.56 = .223, nada = .219
My reloading stuff is all boxed up, while I'm remodeling a house, so I cant go grab a bullet and check it out with the calipers. So what am I missing?
Old Turd- Deplorable- Unrepentant Murderer- Domestic Violent Extremist
Just "Campfire Riffraff and Trash"
This will be my last post! Flave 1/3/21
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Campfire Outfitter
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Campfire Outfitter
Joined: Oct 2007
Posts: 14,260 |
You are confusing the groove diameter with the bore diameter.
Its all right to be white!! Stupidity left unattended will run rampant Don't argue with stupid people, They will drag you down to their level and then win by experience
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Joined: Aug 2005
Posts: 63
Campfire Greenhorn
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Campfire Greenhorn
Joined: Aug 2005
Posts: 63 |
Looks like the metric designation is referring to bore diameter whereas our imperial designations are typically groove diameter.
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Joined: Jun 2004
Posts: 7,177
Campfire Tracker
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Campfire Tracker
Joined: Jun 2004
Posts: 7,177 |
Looks like the metric designation is referring to bore diameter whereas our imperial designations are typically groove diameter. Except when they are not. 218 Bee, 250 Savage, 256 Newton, 300 Savage, 30/30, 30/40/ 30/06, 350 Rem, to name a few. In the end, it's all pretty meaningless. GD
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Joined: Nov 2009
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Campfire Ranger
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OP
Campfire Ranger
Joined: Nov 2009
Posts: 15,885 |
You are confusing the groove diameter with the bore diameter. Yeah, you're right!
Old Turd- Deplorable- Unrepentant Murderer- Domestic Violent Extremist
Just "Campfire Riffraff and Trash"
This will be my last post! Flave 1/3/21
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Campfire Tracker
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Campfire Tracker
Joined: May 2011
Posts: 5,800 |
The numbers are all over the place. The 8x57 was also called 7.92x57. The 325WSM is an 8mm (0.323"). They all need "-ish" added to the end of their names.
Whatever you said...everyone knows you are a lying jerk. That's a bold assertion. Point out where you think I lied. Well?
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Joined: Sep 2010
Posts: 3,998
Campfire Tracker
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Campfire Tracker
Joined: Sep 2010
Posts: 3,998 |
The numbers are all over the place. The 8x57 was also called 7.92x57. The 325WSM is an 8mm (0.323"). They all need "-ish" added to the end of their names. Too funny! Except for my wife who is from Minnesota, to her "ish" means" Yuck!"
I am continually astounded at how quickly people make up their minds on little evidence or none at all. Jack O'Connor
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,119 |
Then there are the two different 7.9x57 groove diameters, .318" and .323"--though the bore diameter is the same.
Plus, 7.9mm and 8mm....
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Campfire Outfitter
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Campfire Outfitter
Joined: Jun 2019
Posts: 9,908 |
There's 25.4 MM to an inch, but simply doing the math doesn't always work. For instance, if we multiply 25.4 by .308, the calculator spits out 7.823 - - - - -not the 7.62 that we usually associate with ".30 caliber". Inch/MM conversions are a SWAG at best! Jerry
Ignorance can be fixed. Stupid is forever!
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Joined: Jun 2004
Posts: 44,832
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,832 |
There's 25.4 MM to an inch, but simply doing the math doesn't always work. For instance, if we multiply 25.4 by .308, the calculator spits out 7.823 - - - - -not the 7.62 that we usually associate with ".30 caliber". Inch/MM conversions are a SWAG at best! Jerry 7.62 / 25.4 = 0.3 the .300" bore size associated with 30 cal
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Campfire Outfitter
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Campfire Outfitter
Joined: Oct 2002
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The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system!
Dog I rescued in January
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Campfire Regular
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Campfire Regular
Joined: Feb 2006
Posts: 1,416 |
The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system! I could agree with you but then we would both be wrong!Jerry
Minnesota; Land of 10,000 Taxes
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2005
Posts: 38,867 |
The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system! I would agree with you so then we could both be right!
Not a real member - just an ordinary guy who appreciates being able to hang around and say something once in awhile.
Happily Trapped In the Past (Thanks, Joe)
Not only a less than minimally educated person, but stupid and out of touch as well.
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
Posts: 41,974 |
The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system! I would agree with you so then we could both be right! Nope, you'd both be still wrong. The metric system is perfect; 10mm = 1cm - 100cm = 1 metre - 1000 metres = a kilometre 10ml = 1cl - 100cl = 1 litre - 1000l = 1 kiloletre Water boils @ 100*C & freezes at 0*C (roughly)
Paul.
"Kids who grow up hunting, fishing & trapping, do not mug little old Ladies"
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Campfire Outfitter
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Campfire Outfitter
Joined: Jan 2016
Posts: 12,009 |
JOC wrote a good chapter on it in the Rifle Book titled "how Cartridges are Named" I think. Some for bore diameter and some for groove diameter. I've never understood the rant about metric. metric is what it is. We here in the US have grown up with the imperial system so we're comfortable with it. Europe has the metric system and our autos are a mix of the two. You can convert and machine just as precise either way. Threading metric with an inch lead screw lathe that's geared for it isn't as easy as cutting imperial threads. Cutting metric threads on a metric geared lathe isn't so easy either. The thread dial is a mass of gears. Then there's British Whitworth.
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Campfire Ranger
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OP
Campfire Ranger
Joined: Nov 2009
Posts: 15,885 |
I had forgotten about British Whitworth, glad you mentioned it. Several years ago, I was working for a company that made machinery, thus there was a machine shop. Once in a while, they would take in machines, not made by them, for repair. Usually machines that no one else would touch. One day, one of the foreman came by my office and asked if I would come look at a machine they were having problems with. None of our bolts would fit. A machinist helper had disassembled the machine and thrown away the old bolts. Gonna replace them during reassembly, but nothing we had would fit, different threads. Found one of the old bolts and none of our thread gauges matched the bolt. Didn't know what we had.
I was told they took the bolt, to the the place where they bought bolts, and they figured out it was Whitworth. Guess the machine had been made somewhere in the UK, but that's just a guess. Last I knew, they were trying to find the correct bolts, instead of having to tap out the holes. Never did find out what they did.
Old Turd- Deplorable- Unrepentant Murderer- Domestic Violent Extremist
Just "Campfire Riffraff and Trash"
This will be my last post! Flave 1/3/21
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Campfire Regular
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Campfire Regular
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Posts: 965 |
The bullet does the job, so I don't really care about land or groove diameters. This confusion should have been avoided from the beginning.
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Campfire Outfitter
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Campfire Outfitter
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The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system! I could agree with you but then we would both be wrong!Jerry Ok wise guy divide a meter by 3, divide the meter by 4, What is the metric equal of .001? Notice anything here?
Dog I rescued in January
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Campfire Outfitter
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Campfire Outfitter
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Nope, you'd both be still wrong. The metric system is perfect; 10mm = 1cm - 100cm = 1 metre - 1000 metres = a kilometre 10ml = 1cl - 100cl = 1 litre - 1000l = 1 kiloletre Water boils @ 100*C & freezes at 0*C (roughly) The metric system, being invented by the French, cannot be perfect. At least we can never let them think that it is, they're arrogant enough already.
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Sep 2009
Posts: 41,974 |
The world needs to come to grips with the fact that the inch/foot/yard measuring system is far better than the damned metric system! I could agree with you but then we would both be wrong!Jerry Ok wise guy divide a meter by 3, divide the meter by 4, What is the metric equal of .001? Notice anything here? 1 Metre = 100cm/3 = 33.3cm or 333mm 1 Metre - 100cm/4 = 25cm or 250mm 1" = 2.54cm/1000 = 0.00254mm Don't see your problem
Paul.
"Kids who grow up hunting, fishing & trapping, do not mug little old Ladies"
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