Here's information for the standard multi-player semi-auto rifles. There's also partial information for the M39 EMR, which you can only unlock through playing in co-op mode. I don't play co-op, so I'm unable to analyze that weapon.
I assume we're talking about these:
- MK11 MOD 0
- M39 EMR (Co-Op unlock)
There's no significant difference between their unlocks. Their origin, Russian (SVD and SKS) vs. NATO (MK11 and M39), will affect which faction's holographic sight and red dot sight they get first, for example. But ignoring very minor differences, the unlock progressions are the same.
This earlier question points you to damage information for these weapons, from a weapon stat spreadsheet that includes other information as well.
Here's a table copied from that answer (thanks Jeff Atwood). For comparison, player health on a standard server is 100.
RANGE 5 10 15 20 25 35 40 50 60 80 100 meters
SVD 50 50 49 48 47 44 43 41 38 34 34
MK11 50 50 49 48 47 44 43 41 38 34 34
SKS 34 34 34 34 33 32 32 30 30 30 28
M39 50 50 49 48 47 44 43 41 38 34 34
So the SKS is lower than the others, but still decent on a per-shot basis.
Rate of Fire
Unfortunately the spreadsheet mentioned above says nothing about semi-auto rate of fire as of this writing. The problem is that semi-auto weapons don't have a rate of fire in the same sense that auto weapons do.
You'd think ROF is just "as fast as you can click, but with an upper limit enforced by the weapon." And while that's roughly true, it's not quite that simple.
Empty a few semi-auto clips as fast as you can. You might expect to hear a regular rhythm constrained by the weapon's upper limit, but you'll actually hear something pretty irregular, including some very fast spurts. There almost seems to be a sweet spot, meaning it's less about how fast you click than about whether you click at just the right times.
Given that caveat, here's information on the MK11, SVD, and SKS. I don't co-op, so I haven't unlocked the M39. For a semi-realistic number rather than an optimal (impossible) one, I emptied 10 clips for each weapon, timing with a stopwatch, and averaged the time needed... i.e., there's lots of room for observation error.
So a disclaimer: understand that these numbers are very, very squishy.
Pseudo rate of fire (rounds per minute)
I have no great idea for measuring this precisely.
What I did was to measure—on my screen with an actual ruler—the distance between the white reticule brackets when the weapon is equipped. Obviously the mm measurement will vary with screen size, but it'll give you a basis for comparison between weapons.
Note that this was not scoped in. Once you scope in, the reticule's brackets disappear, making it look like every weapon is equally accurate... which I doubt is true. My leap of faith is to assume that differences when firing from the hip will translate into differences when you actually aim. That could be wrong.
I've included a couple of other weapons for comparison.
Smaller number = better (tighter) spread.
Semi-Auto spread in mm
Weapon Stand Crouch Prone
MK11 45 39 33
SVD 45 39 33
SKS 33 26 21
Other weapon spreads for comparison
Weapon Stand Crouch Prone
AK-74M 33 26 20
M9 14 14 14
G17C 10 10 10
The SVD and MK11 are pretty comparable, as you'd expect since they're the starting weapons for the two factions. Personally I feel the SKS works well for front-line recon play. It's less powerful than the others per shot, but it has less spread and a slightly higher ROF.