.270-308 Do we need one?
03-11-2008, 06:17 AM
#31
Boone & Crockett
Join Date: Feb 2003
Posts: 10,679
RE: .270-308 Do we need one?
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
03-11-2008, 08:03 AM
#32
Join Date: Apr 2005
Location: Missouri
Posts: 1,429
RE: .270-308 Do we need one?
ORIGINAL: eldeguello
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
It went something like this:Shato: "I'm looking for a bullet for my 22-250. It shoots 50 gr. Nosler ballistic tips well, but not 50gr. Sierra varminters. I've always been partial to sierra bullets, any thoughts?
Sierra bullet Nerd:
"Well, Sectional density this blah blah, blah, Ballistic coefficient that blah blah blah, Cosine this blah blah blah, Tangent that blah bla blah. No if you divide the square root of the earth circumfrence by the cube root of the Diameter. and multiply the product by the tangent of the cosine of the lunar eclipse. then use quantum physics to determine the twist rate of your barrel. blah blah blah.....................
Shato:
"maybe I'll try Blitzkings, thanks!" hang up
03-11-2008, 09:55 AM
#35
Nontypical Buck
Join Date: Aug 2004
Location: Michigan
Posts: 3,329
RE: .270-308 Do we need one?
ORIGINAL: ShatoDavis
Do you work for Sierra bullets? Because I called Sierra a few weeks ago, and the guy who I taked to spurted off a line of BS like that at me too. I didn't know what the hell he was saying, but he sure did say a lot of it! It went something like this:
Shato: "I'm looking for a bullet for my 22-250. It shoots 50 gr. Nosler ballistic tips well, but not 50gr. Sierra varminters. I've always been partial to sierra bullets, any thoughts?
Sierra bullet Nerd:
"Well, Sectional density this blah blah, blah, Ballistic coefficient that blah blah blah, Cosine this blah blah blah, Tangent that blah bla blah. No if you divide the square root of the earth circumfrence by the cube root of the Diameter. and multiply the product by the tangent of the cosine of the lunar eclipse. then use quantum physics to determine the twist rate of your barrel. blah blah blah.....................
Shato:
"maybe I'll try Blitzkings, thanks!" hang up
ORIGINAL: eldeguello
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
It went something like this:Shato: "I'm looking for a bullet for my 22-250. It shoots 50 gr. Nosler ballistic tips well, but not 50gr. Sierra varminters. I've always been partial to sierra bullets, any thoughts?
Sierra bullet Nerd:
"Well, Sectional density this blah blah, blah, Ballistic coefficient that blah blah blah, Cosine this blah blah blah, Tangent that blah bla blah. No if you divide the square root of the earth circumfrence by the cube root of the Diameter. and multiply the product by the tangent of the cosine of the lunar eclipse. then use quantum physics to determine the twist rate of your barrel. blah blah blah.....................
Shato:
"maybe I'll try Blitzkings, thanks!" hang up
Tom
03-11-2008, 02:34 PM
#37
Fork Horn
Join Date: Jan 2008
Posts: 159
RE: .270-308 Do we need one?
We had a 270win and then 30-06 why didwe need the 280rem? But it is nice to have the choice. If the 277-08 came before the 7mm-08 the latter would not be necesarry, but its a nice cartridge to have. And if there is a 277-08 the 260rem wouldn't be necesary. Or would it? Like choice
Use full 277 bullet weights forthe 277-08110/115, 130, 140, 150, 160gr.
And for the 7mm-08 139/140, 145, 150/154, 160, 175gr.
The last listed for each is most likely too heavy for good velocity.
I would like the 277-08 to match my 358win for th same reason I have a 270win & 35whelen. But the 7mm-08 will work just fine.
The 08 & 06 cases make sense in .257/.277/.308/.358 all would be or are great cartridges but any that shoot the gap are OK with me!
Use full 277 bullet weights forthe 277-08110/115, 130, 140, 150, 160gr.
And for the 7mm-08 139/140, 145, 150/154, 160, 175gr.
The last listed for each is most likely too heavy for good velocity.
I would like the 277-08 to match my 358win for th same reason I have a 270win & 35whelen. But the 7mm-08 will work just fine.
The 08 & 06 cases make sense in .257/.277/.308/.358 all would be or are great cartridges but any that shoot the gap are OK with me!
03-11-2008, 04:22 PM
#38
Spike
Join Date: Feb 2007
Posts: 90
RE: .270-308 Do we need one?
ORIGINAL: bigbulls
That's what I was saying but I guess I was proven wrong. [&:]
As for .264" and .284" bullets being ballistically superior to .277" bullets - theballistic properties of any caliber bullet depend on two factors-their sectional density (weight IN POUNDS divided by the square of the diameter in inches)and their form factor, or shape. (Sectional density / form factor = ballistic coefficient-B.C.) So if you take bullets of any given caliber, givethem a specific sectional density and identical form factors,they will ALL be ballistically IDENTICALregardless of their diameter - .264", .277", .284, .308", whatever. Of course, to remain ballistically identical, the shape has to remain the same, and weight must increase as diameter increases to maintain identical SD's.............
Agreed that the same S.D.'s and forms would produce the same B.C.'s... Can't argue with math. However, I was just saying that .277 bullets are ballistically inferior because we round off our bullet weights. A 120 grain .264 bullet and 140 grain .284 bullet both have higher S.D.'s than a 130 grain .277 bullet. Therefore, theyshould have higherB.C.'s. Also, for whatever reason, many .264 and .284 bullets happen to have really good streamlined shapes, which improves their B.C. relative to S.D.
This is perfectly demonstrated by the fact that the 140 grain .284 Nosler Ballistic Tip's B.C. is .485 and the 140 grain .277 Ballistic Tip's B.C. is only .456, even though it's S.D. is .013 higher than the .284's.That math doesn't work, unless the .284 bullet is designed more aerodynamically... Which mean's it's ballistically superior. Everyone agree?
And the original question per the title of the thread was whether or not a .27-08 is NEEDED, not whether people would buy it. If it's not obvious to some why we don't need a .27-08, then those are the exact same people who are the reason it might sell anyway. We do, afterall, live in the most excessive, over-the-top nation on Earth.
03-11-2008, 04:32 PM
#39
Spike
Join Date: Feb 2007
Posts: 90
RE: .270-308 Do we need one?
[quote]ORIGINAL: TJEN
We had a 270win and then 30-06 why didwe need the 280rem?
Remington was trying to match the .270 with a cartridge that would work through their new semi-auto rifle. The semi-auto action couldn't handle the pressures of a .270 load. This is why .280 ammunition still isn't loaded to as high of pressures as the .270. However, since the .280 bullets tend to have higher ballistic coefficients, they still come really close and sometimes even beat the .270 in trajectory.
We had a 270win and then 30-06 why didwe need the 280rem?
Remington was trying to match the .270 with a cartridge that would work through their new semi-auto rifle. The semi-auto action couldn't handle the pressures of a .270 load. This is why .280 ammunition still isn't loaded to as high of pressures as the .270. However, since the .280 bullets tend to have higher ballistic coefficients, they still come really close and sometimes even beat the .270 in trajectory.
03-11-2008, 06:01 PM
#40
Boone & Crockett
Join Date: Feb 2003
Posts: 10,679
RE: .270-308 Do we need one?
This is perfectly demonstrated by the fact that the 140 grain .284 Nosler Ballistic Tip's B.C. is .485 and the 140 grain .277 Ballistic Tip's B.C. is only .456, even though it's S.D. is .013 higher than the .284's.That math doesn't work, unless the .284 bullet is designed more aerodynamically... Which mean's it's ballistically superior. Everyone agree?
It's not, the 140 grain .277 bullet is ballistically superior to the same weight bullet in .264".
To say one bullet caliber is superior to the other is false.
I understand your point but...............
