Just purchased a Savage Axis chambered in 7mm-08.

I looked at the trajectory and ballistic statistics which is what drove me to purchase that calibur.   I am also not a legit sharpshooter....yet so I was sold on the fact that the 7MM has a flatter trajectory.

My question is, my Remington R1 1911 chambered in .45 ACP  shoots 230 gr cartridges.  Why is the 7MM-08 round only 120-140 gr?  Why does a pistol cartridge have more grain to it than a hunting round?

Well it's quite simply because it has a much larger diameter.

Think about it like this, if the two bullets were only cylinders (no curve to them) the 45 would require a much larger cylinder because it has a much larger diameter 451" vs 284"

This isn't always the case though. A .308" bullet can be up to 220 gr while a 451" ACP can be as low as 185gr.

It really depends on the length of the bullet, which they vary to get better ballistics, which leads to a larger mass and less wind resistance.

The reason is balance....

Every rifle is designed to fire a bullet of a particular length and weight.  It is entirely possible that a factory could make a 230 grain 7mm bullet.  Or a 60 grain one.  However, neither of these would work because no rifle will stabilize them or shoot them at common speeds.  Most bullets are designed to be used at muzzle velocities of about 2400-3200 fps.  So, you have 7mm bullets in weights like 120, 140, 160, and 175.  The big 7mm Magnums will do okay with 160s and 175s, but muzzle speeds with the 7mm-08 would be too slow to be very useful (down to about 2300 fps for 175s in 7mm08).  So, factories make loads with 120 and 140 grainers.  And these run at 2500 to 2900 in your 7mm08 -  just perfect speeds for useful expansion.  A 200 grain 7mm bullet would also be sooooo long, the typical rate of twist in your rifle would never stabilize it.  It would likely tumble.

At one time, before the 1880s, militaries used big slow blackpowder cartridges like 45-70 and 450-577 Martini. These fired 400 and 500 grain bullets at slow speeds.  In the 1880's they started moving towards smaller caliber bottle necked cartridges like the French 8mm (232 grainer) and the early German 8mm (225).  We followed suit with the .30-03 firing a 220.  Most of these used round nosed bullets that were big slow bullets by our standards, but super fast during the day.

During world war 1, we learned that faster bullets travelled farther, with less drop.  You  cannot simply take a 220 grain bullet and decide to push it faster.  Guns blow up.  The only way to get a bullet to go faster with safe pressure is to use a lighter bullet. So we scrapped 220 grain bullets and starting using  streamlined smaller lighter bullets like 150's in 30-06.  

Same for Paul Mauser.  The original 7mm cartridge was the 7x57mm firing a 173grain roundnosed bullet in mausers 1893 rifles built for Spain.  Speed was about 2200 fps.  That was later changed to a - wait for it -  140 grain bullet at almost 2800 fps.

Virtually all common bottle neck cartridges will do the same thing -  fire a bullet at 2600-3200 fps.  Big magnums go faster.  Smaller cases go slower.  It's al about finding a balance between bullet weight and bullet speed, all at pressures of 50,000 or 60,000 psi or a little more.

Your 1911 uses a big slow bullet.  You can find some pistols that go faster.  357 SIG comes to mind.  However, that is still a matter of using a lighter bullet (125 grains instead of 230) in order to go faster (1300 fps instead of 900).  7.62 x25mm tokarev goes a bit further.  They lighten the bullet to 86 grains in order to go a tad faster.  Pistols simply won't go much faster than this because barrels are short, and no one wants a 5 pound pistol.  A 28 ounce handgun only has so much steel, and therefore can only handle so much pressure.

there ya go.........

Fro

Why is a 300lb man bigger around than a 150 lb man if the same height?