Originally Posted by goodgrouper
I sure would like to have someone explain to me how the 250 grain SMK can be a FMJ and the 300 be so much more explosive. I just don't get that. The sectional density of the 300 is way higher and both bullets are made of the same jackets and I presume the same lead.
I'm new to the big 338 arena, but I have smacked 3 whitetails with the 300 smk from the new long gun this season. 2 were just under 200 yards and one was at 475 yards. I'm pushing the 300 SMK at 2965 fps from a 34 inch barrel with 105 grains of US 869 in a 338/300 RUM. All had .338" entry holes with near explosive results after a few inches of penetration. I figure that the 300 SMK opens quicker than the 250 SMK because the non-bonded 300 SMK core itself has a higher SD than the core of the 250. I would guess that at impact the less dense jacket of the bullet would slow down faster than the core, causing the core to slam into the nose of the bullet and pry open that tiny hollow point. The more lead and jump space in the shank of the bullet, the more the nose of the bullet will open on impact, and the greater potential for the hollow point to build hydrostatic pressure...or just grab stuff and fragment. If the 250 SMK does not have enough SD, it may not dislodge the core as violently as the 300 SMK. The bowling ball thing surprises me though. Maybe the hollow nose of the 300 crumpled on the surface of the ball but the point of the 250 penetrated.?
Thanks for the helpful test results. I can't stay on target with the 300's either but they are so accurate that I don't want to experiment right now.