How much larger is the Winchester Magnum .300 VS's the 7.62 NATO round??

Question

From article..

"But there is also a lower-profile effort going on in the 25th Infantry Division to upgrade the venerable M24 sniper rifle from a 7.62mm NATO round to the more powerful .300 Winchester Magnum, a change that would give snipers the ability to hit an enemy out to 1,200 meters."

Why does this Winchester round increase the affective distance by about 400 meters?

And if this new round is this much better then why wasn't it used from day one? Is it new?

article

http://www.marinecorpstimes.com/news/2008/08/army_sniper_080308w/

Answer 1

no,the magnum round was from the late 60's or early seventies.i have a 300 magnum and also a 308 or what you call the 7.62 nato.they are one in the same.the load is heavier in the magnum.the new 300 short magnum may be a better round and compairable in weight to the 7.62.a good sniper can make the 7.62 get out and kill beyond 1200 meters.the difference isn't worth the cost as now a lot of them are using the 50 cal.

Answer 2

The 300 Win Mag and the 7.62 and .308 bullets are identical in diameter.  For those of us with knowledge of the subject they are all commonly referred to as 30 caliber cartridges.  The 300 has the inherent accuracy to be a better sniper rifle that either of the other 30 calibers mentioned plus it has more effective range.  The 50 BMG or one of the Barret's is a super-long range set up.

Answer 3

the 7.62 round is basically the same as a .308 which is obviously slightly larger than the .300 round.  But thats just talking about the physical size of the round.  The power comment is referring to the actual muzzle velocity and bullet speed.  The magnum round is considerably faster, so it will then travel farther and give a stronger punch when it hits its target.

I agree with whip - if you are the one flipping the bill, go with the lesser expensive.  The difference isn't worth the cost.