I was looking at using Predators Mark set. Partly because I ended up with 3 items already due to the armour and stats and also because it sounded like a decent 4 piece Bonus.
The 4 piece bonus for this is:
Set Bonus (4):
Talent | Predator’s Mark
Hit 10 shots without switching target to make the enemy bleed for 100% of damage already done by those bullets.
Some people were of the opinion that it may be a total bleed of the 10 shots combined e.g. 10x 25K shots = 250K bleed whereas others thought it would just be the 10th bullet damage e.g. 25K bleed.
I went ahead and tested it with Pistol, SMG and Sniper. I didnt have LMG etc to test but my guess would be it works for ALL weapons:
The last section of the video I put explosives on. Its worth noting that the explosive damage does not seem to be counted for the bleed effect i.e. 25K bullet damage and 10K explosive will NOT give 35K bleed but just 25K bleed again.
So the results are that the 4 piece bonus will take the damage from your last 10 hits from bullet damage (as misses dont reset it) and then inflict an average of these hits as bleed damage every second for 10 seconds giving you a total of 100% extra damage bonus. It would also appear that, if you have hit 10 shots and they are bleeding, the 10 shot "counter" is not reset until the bleed stops i.e. you cant have 2 or 3 lots of bleed on a single target at the same time.
Of course, someone can heal themselves but the bleed will still occur for the remainder of those 10 seconds
Not sure about you but, in theory it looks good for PVP.... Only time will tell.