Pick your poison, do you want a flat shooting rifle that has really light weight bullets that weigh 32 to 40 grains or do you want a somewhat flat shooting rifle that can shoot bullets that weigh 40 grains up to 77 grains. ...A 75 grain bullet going 2800 fps will still be holding onto 514 ft lbs of energy at 500 yards whereas the 204 Ruger shooting a 40 grain V max will only have 404 ft lbs of energy even though it started out at 3900 fps. The 32 grain load which starts at 4225 ...will only have 326 ft lbs of energy at 500 yards. So if you want knockdown power further out the 223 carries it but it will have more drop. With the 204 Ruger you will get a laser like trajectory but have less oomph when you get out there a ways.
+1
It depends on your distances, targets. If you are only concerned about exterior ballistics (which bullet flies flatter), then the 204 generally wins out. If you will be (and I'm sure you are) concerned with terminal ballistics (in a nutshell = killing power), then the 223 MIGHT win (WILL win if you are comparing heavier bullets in 223 with 204 bullets at longer distances). A good range-finder and dialing in your scope will take care of the bullet drop factor - with practice
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