Shawn and GG,
Interestingly enough, my elk that I shot at 607 yards with my 338 AX and the 265 gr AT RBBT would be very similiar in terminal performance to what you would see with the 338 AM with the same bullet impacting at 1000 yards.
At 607, the 338 AX has around 2400 fps retained velocity, my 338 AM should be clipping along just over 2500 fps at 1020 yards with the load I am using which is relatively mild at a 3460 fps muzzle velocity, it would not be hard to push over 3500 fps.
Very similiar terminal velocities between the two rounds are these different ranges. Now I know that RPMs would be different and to some degree that can effect terminal performance as far as expansion and penetration but I do not believe the difference would be measurable.
That 265 gr AT RBBT smacked that 1100 lb bull, hit a rib on the onside, plowed a 4 to 5" hole through both lungs, centered a rib on exiting and made a 1.5 to 2" exit wound on the offside. I Remember seeing the bull go down and noticing the huge blood stain on the offside shoulder which to be honest suprised me that it penetrated so well.
When I say it plowed a 4 to 5" hole though both lungs, I am not talking blood soaked lung material, it was simply gone. It would not have been hard to literally put your fist though both lungs through the penetration path of that bullet.
The path was even and consistant as well, not a huge intital wound channel and then tapper off but just a consistant big hole bored through the chest.
I believe the aluminum tip aids in expansion just enough for good tissue damage but the VERY heavy jacket stops expansion on soft tissue relatively early for deep consistant penetration.
How would it have performed on a hard shoulder impact, no idea but had I known what I do now, I would have aimed to center that big shoulder!!
As far as the 300 gr SMK, its a different beast when driven to 3300 fps at the muzzle. IT will never be a huge expanding bullet without the impact of heavy bone but it expands much more reliably at 3300 fps muzzle velocities then it will in smaller rounds.
Much past 1200 yards, with any round, you will not get much expansion with this bullet in my expansion testing. The AT RBBT on the other hand is a different story.
Here in 3 weeks or so there will be a pronghorn taken with these bullets to test how they expand on light game at long range. There will be a full report on the findings and then onto deer hunting as well. No fear anymore about not enough penetration, if the bullet will fully vent an 1100 lb bull elk, no deer on the planet will be an issue.
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