I have related this before, so please bear with me...I have used the same .243 since 1980..For about 15 years and probably 75 deer or so all I used were 100gr CoreLokts...Didn't have any problems but wanted to try different factory loadings...I tried Remington Premier 100gr SPBT (discontinued), Federal Premium 100gr Sierra SPBT, Federal Premium 100gr Nosler Partition, Federal Premium 85gr Sierra HPBT and Federal Classic 100gr (I think they call it their HotCore), Winchester Supreme 100gr PowerPoint, Winchester White Box Powerpoint, Hornady Custom 100gr InterLokt and the Nitrex 100gr GrandSlam...

I would shoot 5-6 deer with each and sometimes take a high shoulder and sometimes a broadside center lung shot...I never lost a deer so they all "worked"...Sometimes I had an exit, sometimes not...The bullets that were less likely to exit dropped deer closer to where they were standing when hit with a center lung shot...Each deer hit with a high shoulder shot dropped on the spot....

They all worked but the internal damage was more with the "softer" bullets...As a general rule deer shot with a "softer" bullet, through the lungs would run less than 75 yards and many fell from 25-50 yards from the shot, no blood trail but blood at the sight of the hit....Frankly if a deer goes less than 75 yards I will find them and if I have to drop the deer right there I can put it through the shoulder blades....

Now this is what I want a bullet to do....Exit on a center lung shot, especially if the deer is farther than 50-75 yards away, face it when closer the bullet opens up rapidly and you will have that bullet stay in the deer more than one that is 150-200 yards away...Now on high shoulder shots, I could care less if I have an exit, because the deer will drop right there...

You can have too hard a bullet...I had 3 deer in these tests that ran 125 yards or so...All were hit with the Remington Premier 100gr SPBT...These are the hardest bullets I ever shot in a .243, on lung shot deer the exit was smaller than a quarter...I had a decent blood trail, but they taught me that a bullet can be too hard...They would always exit, even on high shoulder shots....

Deer are remarkable animals, easy to kill if hit properly and can go a long ways if not...Several years ago my brother and I were hunting together, on the ground beside a winter wheat field...Several does came out, we both picked one out, he counted to 3 and we both shot....Ended up shooting the same doe...Him with a .270, me with a .243..Both using Sierra GameKings, both had an exit, he hit 3-4 inches behind the shoulder, I hit on the opposite side when she spun around, just behind the shoulder....That dang doe ran about 60 yards or so and fell 15 yards in the woods....She couldn't have weighed more than 100 pounds, yet she took two good hits....That deer made me realize that a bigger hole through the lungs does not always mean they will drop quicker....Both shots were killing shots, she just held her breath and left the field....