ORIGINAL: stubblejumper
I have two 300 ultramags and use the 180gr tsx in both.I use 88gr of r-25 in one rifle and 93gr of r-25 in the other rifle.One rifle produces 3360fps and the other 3380fps.The difference in powder charge seems large for such similar velocities but I m using different lot#s of powder for each and the barrels and throat lengths are different as well.In both cases the col is 3.670" and the primers are fed-215.
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Holy cow, your kidding. Now thats wild. 5gr delta same velocity. wonder what would happen if you swapped ammo between guns. I wonder if the dominating factor is powder lot or rifles. I would be leary shooting the 93gr load in the other rifle as you probably are.
I got up to 92gr RL25 and 180gr TSX before bearly seeing pressure signs.