since the 7.62x54r put holes the size of your fist into people,imagine what the 14.5 would do.
Doesn't exactly work like that. You're just showing kinetic energy, and not discussing terminal ballistics.
In terminal ballistics, the amount of tissue damage done is a factor of caliber, projectile length, and the distance at which it yaws, OR in some cases, how much fragmentation occurs, and the distance at which it fragments.
In the case of the bullets at hand:
7.62x54mmR = 0.31 cal, 3.33cm long (Type L 148gr Ball)
.50 BMG = 0.51 cal, 5.87cm long (M2 Ball, length also common to many .50 bullets)
14.5mm = 0.586 cal, 5.1cm long (BS/API)
14.5mm projectiles are usually shorter, with the longer cartridge packing more powder, accelerating the projectile to higher velocities.
The difference between the diameter is fairly irrevelant, and .50 BMG/7.62x54mmR perform pretty much the same as 7.62x51mm M80 Ball (what I'm talking about is they yaw at the same distance) so, with 14.5mm actually being SHORTER than .50 BMG, and assuming that it performs not unlike M80 since it has no unique attributes (such as an air-pocket in the tip, like 5.45mm) it would likely create smaller exit wounds than .50 BMG, or at least very comparable.
While I cannot tell you the size of an exit wound after 20cm penetration for .50 BMG Ball, I can tell you that the AMAX cartridge (which are much longer than .50 BMG ball and also sometimes expand) creates ~7-8 inch wide exit wounds. Thus one can be certain that 14.5mm will produce smaller exit wounds than that.
Edit: Note that some 14.5mm projectiles are longer than 5.1cm, and even longer than 6cm. I do not know all the exact details, but the ORIGINAL 14.5mm BS API 65.5g projectile was 5.1cm long. Thus one can say that there may be alot of performance difference with 14.5mm cartridges, but of course, since they'll all reliably stop a man in a single hit, that difference seems irrelevant.
I'll attach this image again to help illustrate my point.
14.5mm will probably look just like .50 BMG, with potentially more temporary cavitation.