Hi JagMagMan,
The biggest problem any manufacturer has in designing a bullet is to get it to perform within a "set of parameters". The same bullet that makes a lightning quick kill on a broadside lung shot on a whitetail at 275 yards from a .308 Winchester......will likely fail miserably if shot from a .300 RUM on a frontal quartering shot on that same whitetail. If it is "soft enough" to open at long range from medium velocity cartridges.....it will likely "nearly explode" when pushed from an ultra fast cartridge and hits its target up close! Premium bullet manufacturers try to overcome some of these "problems...(ie. variables)...by designing in features to answer
both sets of circumstances. Like the Nosler Partition. It is designed to rapidly open the front portion of the bullet and transmit lots of trauma even when impact velocity is low. It also has a partition dividing the core....so the rear portion of the bullet can not come apart...and therefore continues to penetrate. But even the best of bullets are not "perfect".
And it is hard to know for certain that the corelokt "failed" on the above described scenario. It did after all penetrate "through and through" on a broadside shot....and created enough trauma to kill the deer. (Though it ran about 80 yards.) But still, from that instance it would be hard to draw a conclusion of failure. If the "hit" was through the lungs...and placed high through the lungs.....the lungs would have to "fillup to the entrance or exit holes" prior to running out. I have hit deer in the lungs (and blood was "sprayed out" at the point of impact...but then no more blood, (or very little), until the lungs were full of blood. And usually the deer is dead, or nearly so, by then.
Quite a number of years ago I loaded some .30-06 and .308 Winchester cartridges using both Sierra's 150 and 170 grain .30 caliber flat nose bullets. These bullets were intended to work....and open up....at .30-30 velocities. I loaded these bullets to roughly .300 Savage velocities. I wanted the bullets to expand "very rapidly"....but not to explode on the surface. And in approximately 9 out of 10 unsuspecting deer hit with those loads....did nothing but drop. Very few ever did any thing other than drop...or give a convulsive leap. But one day my wife jumped a big doe from the hilltop above me. As she came trotting down the hill I shifted my position to get ready for the shot, and she saw me at about 20 yards. She did not try to change directions...but dropped her head and flat out "flew past me". At nearly muzzle contact distance I shot once and saw nothing but an eruption of "purple-red" in my 2X scope. She was over the "bench" so fast I never got another shot. As I gathered my things I heard my wife yell and ask if I had shot. I told her I had and pointed out my "things"...pack...scent...etc. and told her to stay with the gear while I quickly followed the deer. We hunted public land in Pennsylvania...and you don't waste time recovering your deer.....or someone else will! That deer travelled down hill nearly 100 yards. The bullet had hit the bone in the right front shoulder and had turned her lungs and heart into liquid jelly. You could spin her right front leg in an entire 360 degrees. But the bullet did NOT exit. Now based on that incident you could conclude one of several things. The bullet did not exit....so did it fail? The deer did not drop immediatly...so did the bullet fail? The bullet killed the deer and I recovered it...so did it succeed? The internal trauma to the chest cavity was massive....so did it succeed?
The reason I had loaded those bullets that way was to try to introduce massive trauma internally and put the deer down as quickly as possible. Both I, and people I know, have hit deer fatally and lost them to another "hunter" because the deer had run 50 - 100 yards and someone else got a bullet in it. Or even once or twice.....didn't even shoot it....just found it first and tagged it. So rather than argue with someone about who made a killing shot...the idea was to "put them down quickly". And it did that....nearly all of the time! But I knew not to try to take a shot other than through the ribcage. If I would have tried to push those bullets length wise through a deer.....it would have failed to penetrate sufficiently....and made a terrible mess of an external wound.
I related on an earlier thread on this site that I once observed my brother shoot a medium sized whitetail at "maybe" 30 yards. I visually saw her near side shoulder momentarily collapse...and pop back out. (Looked like someone had stood on her back and smashed her shoulder with a 12 pound hammer.) She flipped upside down, all four hooves flailing, then regained her feet and quickly disappeared up the hill. I never even thought to yell at him to try to get another shot. Not only had it happened quick....but I honestly thought we'd have a dead deer on the ground within 50 yards or so. She topped that hill, circled to the other side of it, went down the far side, to the heaviest of cover at the river's edge.....where we lost her tracks among the myriad of other deer tracks. We spent four hours looking for her that afternoon....and never saw her again! I have know idea what happened. Bullet might have "sailed through" and failed to expand. Bullet might have "blown up" on the near side shoulder and never reached the vitals. To this day.....I have no honest idea what happened. Just what I saw! In case you're wondering...he hit her with a Hornady Interlock, 150 grain .30 caliber bullet, out of a .30-06....standard velocity reload. That same bullet and load....from that same 760 carbine....had killed alot of other deer....but it dang didn't kill that one, (at least we didn't recover it). And she had travelled probably better than a quarter mile to reach that river. Go figure!?!
My point of all the above is simply this. You might get the kind of performance you'd like to get 95 times out of a 100. And if you did...would that mean the bullet worked? Or failed? I guess which of those times someone asked! But people do have a tendency to remember the 5% of the failures over the 95% of the successes. (Though often they will only admit to their successes
.)
I don't know what to tell you about that particular load from Remington out of your 7mm on whitetail. What I do know is that even on a good lung shot animal....frequently there will not be alot of blood visible on the ground....unless the exit hole is rather low on the anatomy of the animal. If the exit hole is higher up on the shoulder you frequently won't get massive amounts of blood within the short distance most animals will run with their lungs shot through! Which is exactly the reason why I always question people I know when they tell me they got a shot...but missed! (I've actually convinced my brother-in-law, and two separate friends......all of whom I knew could shoot.....to go back out with me and look some more. In all three cases...we recovered dead deer!)
If you lack confidence with that bullet and load....then by all means switch! But you may find out that the next load doesn't do anything better than the one you just left!
Best of luck to you though with your search!
P.S. I don't have a financial interest in Remington....or any other ammo manufacturers either
!