Which is larger 7mm rem mag or 300 win mag?

Answer 1

7mm shoots a .284" dia. bullet.

300 win mag shoots a .308" dia bullet.

The ballistics are similar, depending on the range. The 7mm bullets have higher ballistic coefficient than .308 caliber bullets of similar weight. Example: a 7mm 175 grain sierra spitzer boat tail (spbt) has a ballistic coefficient of 654 a .308 caliber 180 grain spitzer boat tail has a ballistic coefficient of 535. What that means is the 7mm bullet will lose less energy and velocity as it move down range toward the target. This is most important at longer ranges. Example: a 7mm 175 grain spbt fired from a 7mm rem mag leaves the barrel at 2900 feet per second and has 3267 foot pounds of energy. At 400 yards it has a velocity of 2354 feet per second and 2153 foot pounds of energy. a .308 cal 180 grain spbt fired from a 300 win mag leaves the barrel at 3000 feet per second and has 3597 foot pound of energy. At 400 yards it has a velocity of 2326 feet per second and 2162 foot pounds of energy. Nearly a dead heat, certainly not a significant difference in bullet performance. AT 600 yards things begin to change: 7mm rem mag, 2105 feet per second and 1721 foot pounds of energy. 300 win mag 2047 feet per second and 1642 foot pounds of energy. The ballistic advantage of the 7mm bullet continues to make gains on the .308 cal bullet out past 1000 yds. Not much difference, but an advantage for the 7mm bullets, because of the greater ballistic coefficient. One could shoot a heavier .30 caliber that had a higher ballistic coefficient, but as the weight of the bullet goes up so does the recoil. The recoil of the 300 win mag firing a 180 grain bullet is already noticeably more than the 7mm rem mag firing a 175 grain bullet.