70-100% Rending on Backstab Hit.
1-4 Bleed Stacks on non-Weak Spot Hits.
Gain Ranged Attack Immunity while sprinting with over 50-80% Stamina.
7-10% Reload Speed for 2.5 seconds after Close Kill. Stacks 5 times.
Using a borderline-SMG for sniping? A bit odd, but it works. Executioner Stance plus a surprisingly accurate autogun ADS means you can just delete huge numbers of specials, elites, and ranged enemies. Keeping up the ES through reloads is trivially easy as long as you pick your next target and re-aim quickly. You should have more than enough ammo to take out every special you see, even if you're not getting head-shots at long range.
The rate of fire makes the Columnus Mk V decent against hordes, but it won't be your primary tool. This is effectively an "ALL THE GRENADES" build. You're regenerating them constantly, hold 4, can get them from Ammo Crates, and often throw doubles. There's not a horde in the world that survives five grenades spammed around.
The grenades bleed stacks mean that they're functional for hordes that come with Maulers, Ragers, and Ogryn, but this is where you'll find that the Combat Blade really shines. The speed and mobility mean that you can dance around enemies while knocking off large chunks of health with crits, bleed, and backstabs. Also, the weapon details damage listing lies. For a weapon that starts with a max of 140 damage on a heavy swing, you can get 1300+ damage hits with crit heavy backstabs, even before Rending. The stat page lists a max in the 800 range.
All in all, you have tools to deal with just about anything. Monstrosities are the weakest part of the build, but the bullet-hose means that you can just keep moving and still put a lot of bullets into weakpoints. And if all else fails, 4-6 shredder grenades will at least do something, and your knife can pile on bleed stacks all day.