Originally Posted by muddober
They are both based on the parent case which is the 8mm Remington magnum. I have not been able to get but about 3860 fps out of mine but at that speed it will shoot less than a 1/2" at 100 yards. My gun is a 700 Remington with a 26" Hart stainless heavy barrel. If I can see a jackrabbit that is standing still and there is no wind he is in trouble. Most of my shooting is on my own farm so I know my distances. We have several pivots for irrigation and the fields are 880 yards accross making it easy to judge distance by the track of the pivot.
Thanks for the info I was using 8mm remington mag brass and necking it down to 7mm. I did not know that they were using it also for 257. That is one fast rifle for a 100 gr pill.