Large-calibre rifle rounds and ranged accuracy

Assuming a completely standard round design, is there much to differentiate the long-range performance of a heavy-calibre round (such as .50BMG/Russian, 14.5 Russian or 15.5 FN) other than the additional drag caused by a fatter projectile?

And if not, why do numerous 'sources' (google the phrase, it's on every single page that references 14.5 Russian. Verbatim.) claim that "the accuracy of 14.5x114mm degrades significantly beyond 1000m"? Is this true, and if so why? And why does this not affect .50cal rounds?

And, as a final question, for a long-range anti-personnel round, is a saboted sub-calibre round preferable to a full-bore slug? And would such a round also be suitable for certain types of anti-material work, such as defeating electronics? EOD work would presumably continue to require a full-bore round to accommodate explosive warheads such as Raufoss.

well "standard round design" is a bit misleading. If you mean a cylinder that comes to a point, yes they both share that design.

But the /fatter/ projectile of the 14.5mm is likely not designed for long range performance with regards to shape-- it may have be easier to make in a less efficient form with the idea being heap enough lead and youll hit what youre trying to kill.

but to try to compare the designs as being "standard rounds" as if that meant they were of similar form aside from diameter is really wrong fundamentally.

Not mention it may be that ballistically the 14.4mm is just in a bad spot with its form for this size round.

The 14.5mm fires a lightwieght projectile (compared to ther power-loading) to achieve ridiculous velocities. So now you habe a light 'n fast flying brick of armor-piercing death.

After 80 meters or so, it was decided that the guns lose enough penetration due to these things already, that it was not deemed effective for engaging vehicles beyond the 1km mark.

And 14.5mm vs infantry is kinda like shooting a sea-sparrow at a somali pirate. So why optimize the round for doing this to 2km?

Actually the exact phase coems from an article on the M6 gepard:

http://www.onwar.com/weapons/infantry/fire...Gepard_AMR.html

And the phrase got copied into the wiki article on the 14.5x114mm round and hence to infinite articles that are simply copy pasta from wikipedia.

Its not where near as much of an issue as the gepard suggests (and which seesm to have a lot to do with with too much roudn for a too small gun).

After all the NTW-14.5 claims 2,300m and the various KPVs/ZPUs claim 8000m as effective rnages (not that the ZPUs are terribly accurate as they need a bit of dispersion).

I use 14.5 as my tank's co-axial. Before introduction of the ILS (a TRT-25 rip) in place of the original Commander's RWS, the Commander had a 14.5 as his RWS.

The 14.5 RWS was intended to threaten thin-skin and harass lightly armoured vehicles (IFV/APC) at medium-long range, and engage infantry at close-medium, with the ability to 'snipe' with a hilarious zoom function on a stabilised platform.
Not to mention, my Special Forces snipers like doing sniping the American way, with an anti-material round. Only the 14.5 is a 'backup' weapon to a 'conventional' sniper with a .338, so I was really confused as to the supposed inaccuracy, which is a quality rarely stemming from the bullet itself anyway.

Not sure if you'd already done this, but if you look at the drag equation you figure out pretty quickly that a conventional cartridge design gains range as you scale up. Drag coefficient is staying the same. Frontal area is going up as a square function. Drag is going up as a square function. Kinetic energy is going up as a cubic function. This is why larger bullets have a higher BC.

I'm not sure why 14.5 would be deemed to lose accuracy beyond 1km. It might be a rough way of indicating that commie-made stuff wasn't that accurate to begin with. It's vaguely possible that their form factor is so awful that they're going subsonic at that range, but that seems unlikely. It could also just be one of those "facts" that gets mindlessly repeated.