Got the coilguns lately. I'm not actually convinced that it's necessarily a great idea to use them instead of the sniper rifle.
Pros -
- Much higher damage; two hits should pretty much guarantee a kill on normal difficulty levels IIRC, one hit will frequently be a kill.
- Higher 'throughwall' setting so should penetrate further -- but this reduces damage significantly, and this might actually be a con, because by the time you build your first coilgun the aliens are likely to be wearing armor that heavily mitigates post-throughwall damage, and the civillians OTOH are still fragile.
Tie -
- Exact same accuracy -- same spread value uncrouched, same spread value crouched. The range might be larger (can't recall), but realistically, the sniper rifle is not likely to ever give you an out-of-range error anyway, so any extra range is pretty much a wash on any remotely normal map.
- Same TU cost of 18 for an aimed shot, despite the theoretically present holographic scope.
Con -
- Magazines have small capacity and huge size. The /maximum/ number of shots a single soldier can bring into battle is 10: two rounds in the gun, two two-round reloads in the backpack (taking up most of it!), one two-round reload in the holster (takes up all of it), and one two-round reload in the left hand (which must be dropped before firing). This leaves no room for anything as large as a medkit or plasma pistol. So you make your way to your shooting position, drop the reload from the left hand, and maintain really extreme fire discipline, unless you're willing to designate another soldier as ammo mule.
- This also means that you'll need to spend more TUs reloading per shot actually fired.
- Magazines can't be bought, at least early (haven't run very much past my first manufacturing run).
In contrast, somebody using the sniper rifle can easily carry 25+ rounds, a sidearm (and possibly a reload), and a medikit. Because you can carry more rounds and because they're extremely cheap to replace after the battle, somebody with the SR-1 can take chancier shots. A DF cartridge packs two three-round heavy laser bursts in a much smaller package -- a burst isn't nearly as lethal as the coilgun vs. medium armor, but you can carry quite a few more DF cartridges than coilgun magazines.
So in a wide-open map they're pretty dangerous, but if there's long-range sniper duels where both sides have significant cover and hit odds are looking more like 25% than 85%, the SR-1 or heavy laser might be more reasonable (at least against aliens; there's something to be said for one-shot kills if you're doing multiplayer against humans, because while dropping an alien sniper-wannabe with a Needler to below 50% health means that he'll be shooting wider, a human opponent will presumably pull back for medikit use if possible when wounded. A coilgun hit is much less likely to leave anything left to heal).
The snap shot is also still extremely lethal at close ranges, where an SR-1 might not kill fast enough, but now we're talking more assault role rather than a designated marksman on overwatch.
