What is the difference between the bore performance of .25, .264, .277, & .284? If I have a similar Bullet of 130 Grains for Each and have the same case capacity which one will perform the best? Lets base this on two cases 50 & 70 Grain capacity. Curious how well a .500 BC bullet will perform from each out to 1500 from 300.
Bore Performance Data?
- Thread starter RustyPin
- Start date
"Phoeniceltic -
Howdy !
You might gain some insight by running some numbers through the
“ Powley Computer “. There on free to use on-line versions you can access.
You can also peruse the information manual about his computer.
Look here: embscomputerart.com
Your question to my mind.... asks for a comparison between theoretical cartridges, that vary by caliber. Specifically.... comparing internal ballistics efficiency of the guns / cartridges.
For that, Powley suggests comparison using “Expansion Ratio”.
Again, that’s something the Powley Computer helps with.
As a basic rule... as the bore size goes up, chamber pressure would drop;
all other factors being pretty much equal.
Hope that helps ??
With regards,
357Mag
Howdy !
You might gain some insight by running some numbers through the
“ Powley Computer “. There on free to use on-line versions you can access.
You can also peruse the information manual about his computer.
Look here: embscomputerart.com
Your question to my mind.... asks for a comparison between theoretical cartridges, that vary by caliber. Specifically.... comparing internal ballistics efficiency of the guns / cartridges.
For that, Powley suggests comparison using “Expansion Ratio”.
Again, that’s something the Powley Computer helps with.
As a basic rule... as the bore size goes up, chamber pressure would drop;
all other factors being pretty much equal.
Hope that helps ??
With regards,
357Mag
DaveTooley
Gold $$ Contributor
Your assumption that a fixed bullet weight will have the same BC regardless of caliber is wrong. A bullet with a BC of .500 for each caliber will perform essentially the same regardless of caliber.
If for argument sakes the BC's were the same, the bullet weight the same, case capacity the same, but caliber was the only difference. then the bigger caliber will always push the bullet a higher speeds than the smaller caliber bores shooting a bullet of the same weight.
You can just look at the 308 Winchester + 260 Rem + 7mm08 + 243 Win. as an example...
Loaded to the same pressures ( say 58,000 psi ) with the same amount of bearing surface in the case neck, in a 24" bbl shooting 115 gr bullets ( I know 115 gr bullets don't exist for the 6.5mm caliber).
243 win will shoot it at 3,000 fps
260 rem at 3,100 fps
7mm08 at 3,200 fps
308win at 3,300 fps
You can just look at the 308 Winchester + 260 Rem + 7mm08 + 243 Win. as an example...
Loaded to the same pressures ( say 58,000 psi ) with the same amount of bearing surface in the case neck, in a 24" bbl shooting 115 gr bullets ( I know 115 gr bullets don't exist for the 6.5mm caliber).
243 win will shoot it at 3,000 fps
260 rem at 3,100 fps
7mm08 at 3,200 fps
308win at 3,300 fps
DaveTooley
Gold $$ Contributor
You can't have the same bullet weight/shape in different calibers and have the same BC. It defies the laws of physics. Leave BC's out of this. They are not relevant.
Bullet weight as a ration to bore size changes thus the increase or reduction in velocity.
Bullet weight as a ration to bore size changes thus the increase or reduction in velocity.
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