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641 Posts

i thought a 7.62 x 51 = .308 cal.

7.62 x 39 = .311 cal

7.62 x 54r = .311 cal.

the above conversion makes 7.62mm = .300 cal.

neither .308, or .311 = 7.62mm

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Joined

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641 Posts

i thought a 7.62 x 51 = .308 cal.

7.62 x 39 = .311 cal

7.62 x 54r = .311 cal.

the above conversion makes 7.62mm = .300 cal.

neither .308, or .311 = 7.62mm

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11,374 Posts

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22,657 Posts

Unfortunately there is no standard. We still have the .45-70, and the .250-3000.

i thought a 7.62 x 51 = .308 cal.

7.62 x 39 = .311 cal

7.62 x 54r = .311 cal.

the above conversion makes 7.62mm = .300 cal.

neither .308, or .311 = 7.62mm

I've learned the system, but I gave up trying to understand it years ago!

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47 Posts

Words of wisdom right there.303tom said:Don`t try to make sense of it, it will drive you NUTS...................

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26,163 Posts

Why ask why? Drink Bud Dry.

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12,047 Posts

You've been there too?303tom said:Don`t try to make sense of it, it will drive you NUTS...................

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22,657 Posts

But is that measurement taken from the lands or the groover??Lazzaroni has the most accurate MM designation. Their 7.82 Warbird is an honest .308 diameter. .308 divided by .03937 = 7.82 MM.

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1,642 Posts

The 7.82 Warbird represents the bullet diameter of the round, which is .308.But is that measurement taken from the lands or the groover??

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1,642 Posts

Which grooves? The ones in the barrel, or the ones on the bullet after it comes out???In that case, it should be the sdame diameter as the grooves.

BTW, I was pulling your leg with the last post!

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941 Posts

Hum the 50 bmg is. 502" in dial. How is that not 1/2"?c3shooter said:

Why ask why? Drink Bud Dry.

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941 Posts

Yes dang phone fat thumbs tiny keys. Need to upgrade to a galaxy s3....c3shooter said:Actually, an UNFIRED .50 BMG has a max diameter of .510. On firing it is squeezed to .50.

solve a lot of mysteries for you. Case in point:

The .45 ACP vs .44 Rem Mag comparison-

I shoot my .44 through one BBQ tank and make a

massive dent on the next one, while a .45 only makes

a dent on the first one.

The manual points out that the .44 uses @ 5 times as much

powder.

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1,642 Posts

A .500 S&W actually is .500.Actually, an UNFIRED .50 BMG has a max diameter of .510. On firing it is squeezed to .50.

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641 Posts

wrong..........straight from a .50bmg barrel makerActually, an UNFIRED .50 BMG has a max diameter of .510. On firing it is squeezed to .50.

We make our .50 caliber barrels with a .500" diameter bore diameter and a .510" groove diameter. The twist rate options are 15" (for the 50 BMG cartridge) and 32" and 48" (for black powder guns and limited to 30" finish length).

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