Finding proper bullet diameter for the round used

Servant · January 24, 2012, 03:42 PM

Ok, so when I ask about the diameter of a bullet, I am told "go read your manual." So let me ask this, Where in the manual does it tell you? Example, in "Modern Reloading" in the 45 ACP part, there is a diagram of the round. the diameter for the bullet shows .452, this is not separate for lead bullets, following is frangable, jacketed and lead. In the Hornady 8th edition, it says the diameter is .451. Now, unless I am wrong, we use .451 for jacketed bullets, and .452 for lead bullets. Correct? Reason I am asking is because I am wanting to order some dirty thirty bullets, and because of this issue I want to be sure before I order. I am seeing in both books .308. Is this correct? And if so, it seems there are several rounds that use this diameter. So, can bullets used in a 30-30 be used in a....303 Savage, 300 savage, 308 Winchester, etc.? Is there anything else that needs to be looked at while determining which bullet to get? Enlighten an older youngster!!

Sevens · January 24, 2012, 04:12 PM

Well, there's kind of two different questions in here. First is... what is the diameter of cartridge XXXXX. And the way most of us get that answer is... we just kinda know it.

Like we know that .30/30, .30-06 and .300 Win Mag all use the same diameter .308" bullet. We also know that some are a little odd... like the .303 British is [i]not[/u] the same as our .30 cals and that the 8x57, while referred to as the 8mm Mauser or the 7.92x57 is going to require a .323" bullet.

Most load manuals will tell you this, but not all of them I guess.

The other question is what bullet diameter to I need in cast lead for my handgun? And the basic answer is one-thousandth over the typical size (as you said) but more advanced loaders and casters will tell you to slug your bore and find out EXACTLY what size bullet you need for the best performance.

Slugging your bore involves driving a soft lead ball down the bore and then measuring the diameter of that crushed ball to see exactly what your particular handgun would like best.

TATER · January 24, 2012, 04:41 PM

I Think Ruger actually made the earlier models with .308 and changed later to .310.
7.62X39 is actually .792 mm (.312) not .308 and somewhere around 120-130 grains.. However, It is
More common to see this round loaded with .310 metal Jackets, Hornady makes a couple bullets for this
at .310… With the designation of 7.62x39. All this info should be in your book.

FrankenMauser · January 25, 2012, 12:02 AM

All of the cartidges you listed have a .308" bore size.
(30-30, 303 Savage, 300 savage, 308 Winchester)

Any .308" bullet will work. But, you still need to make sure the bullets are appropriate for the application. I.e.: weight range, shape, toughness/rated velocity, cannelure location, etc.

Quote:

The other question is what bullet diameter to I need in cast lead for my handgun? And the basic answer is one-thousandth over the typical size (as you said) but more advanced loaders and casters will tell you to slug your bore and find out EXACTLY what size bullet you need for the best performance.

Yep. I slugged my .444 Marlin last night (not a handgun, but the concept still applies). The cartridge is supposed to have a nominal .429" to .430" bore.
I found a .439" throat (that's big), .428" lands (true "bore" size), and .432" grooves (what we usually care about).
That means I have a decision to make: go with something that fits the throat (and is big for the grooves); or go with something that fits the grooves, but is small for the throat. Lucky for me, the .444 Marlin's throat is essentially non-existent (less than 0.050"). So, I need a .432" bullet, for optimum performance.

Servant · January 25, 2012, 12:07 AM

that makes better sense than looking for the info. Thank you.

January 24, 2012, 03:42 PM	#1
Servant Senior Member Join Date: December 13, 2011 Location: Louisiana Posts: 116	Finding proper bullet diameter for the round used Ok, so when I ask about the diameter of a bullet, I am told "go read your manual." So let me ask this, Where in the manual does it tell you? Example, in "Modern Reloading" in the 45 ACP part, there is a diagram of the round. the diameter for the bullet shows .452, this is not separate for lead bullets, following is frangable, jacketed and lead. In the Hornady 8th edition, it says the diameter is .451. Now, unless I am wrong, we use .451 for jacketed bullets, and .452 for lead bullets. Correct? Reason I am asking is because I am wanting to order some dirty thirty bullets, and because of this issue I want to be sure before I order. I am seeing in both books .308. Is this correct? And if so, it seems there are several rounds that use this diameter. So, can bullets used in a 30-30 be used in a....303 Savage, 300 savage, 308 Winchester, etc.? Is there anything else that needs to be looked at while determining which bullet to get? Enlighten an older youngster!! __________________ "If you want to lead, you must first learn to serve, for the 1st shall be last and the last shall be first." If you can't run with the big dogs, stay on the porch. Lead, follow, or get out of the way!

January 24, 2012, 04:12 PM	#2
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	Well, there's kind of two different questions in here. First is... what is the diameter of cartridge XXXXX. And the way most of us get that answer is... we just kinda know it. Like we know that .30/30, .30-06 and .300 Win Mag all use the same diameter .308" bullet. We also know that some are a little odd... like the .303 British is [i]not[/u] the same as our .30 cals and that the 8x57, while referred to as the 8mm Mauser or the 7.92x57 is going to require a .323" bullet. Most load manuals will tell you this, but not all of them I guess. The other question is what bullet diameter to I need in cast lead for my handgun? And the basic answer is one-thousandth over the typical size (as you said) but more advanced loaders and casters will tell you to slug your bore and find out EXACTLY what size bullet you need for the best performance. Slugging your bore involves driving a soft lead ball down the bore and then measuring the diameter of that crushed ball to see exactly what your particular handgun would like best. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

January 25, 2012, 12:07 AM	#5
Servant Senior Member Join Date: December 13, 2011 Location: Louisiana Posts: 116	that makes better sense than looking for the info. Thank you. __________________ "If you want to lead, you must first learn to serve, for the 1st shall be last and the last shall be first." If you can't run with the big dogs, stay on the porch. Lead, follow, or get out of the way!

January 24, 2012, 04:41 PM	#3
TATER Senior Member Join Date: November 19, 2002 Location: Mississippi Posts: 963	I Think Ruger actually made the earlier models with .308 and changed later to .310. 7.62X39 is actually .792 mm (.312) not .308 and somewhere around 120-130 grains.. However, It is More common to see this round loaded with .310 metal Jackets, Hornady makes a couple bullets for this at .310… With the designation of 7.62x39. All this info should be in your book.