Thread: 6.5x55 bullet options

I was surfing through the forum and read a few different threads on various bullet types and I've ended up quite confused, so hoping some of you ballistic genius types can help me out with your experience.
I guess I'm also hoping that some of the newbies to hunting might benefit from this discussion too and it might help them make better choices when buying ammo so they lose fewer animals than perhaps the rest of us have, before we figured some stuff out.
When "ballistic tip" or polymer tip ammo started being marketed and we were all told how animals would fall over dead just by the sight of these bullets, I accepted this as truth and bought a pack of Hornady Superformance (blah, blah). Unfortunately, as they had quite a different POI to my Federal ammo, I shelved them. Then one day, after losing a Sika stag (which I'm sure I hit well in the HILAR), got pissed off and decided it was time to re-zero my rifle with these new Hornady SST whiz bang things... With disappointing results!

Here's a couple of photos of the Federal Powershock 140gr, showing entry and exit at 75m.


I thought I had matching photos of the Hornady SST trial, but couldn't find them. But I can say that the damage on exit was far less compelling with exit hole less than half the size and very little cracking or distortion of the other pumpkin (bloody good fun shooting pumpkins btw!! :-D)
A mate shoots .25-06 with SSTs and nailed a huge Sika stag last year at about 80metres, hitting him perfectly through the centre of both 3rd ribs, yet very little expansion of the bullet, so he ran quite some distance before he realised he was dead (:-P). The exit wound was only twice the size of the entry hole.
So, I've had a mate reload some brass with Sierra SPBTs and slowed down the charge a bit to 2560fps MV, which I haven't tried on either pumpkins or deer yet, but they're consistently very accurate on paper. When I've dug some of my Sierra pills out of the clay, they seem to have very little lead left and just a mangled copper jacket remaining (?!)
Reading many comments about "plastic tip shite" or "old school 1960's" "anaemic" bullets leaves a guy feeling like its all too techno and hard, so we just shoot whatever we get and hope for the best.
Perhaps a few of you could enlighten us with exactly how these bullets are supposed to work in different situations?
And why we might choose one over the other? I'm not asking for a full science lesson in bullet aerodynamics or anything, but more about the speed vs distance vs mushroom effect.
Thoughts?