General use Stubber Gungryn
 Ogryn Build - Warhammer 40k: Darktide 

Very easy to use, light attack spam with heavies and special attacks mixed in will deal with most frontline mob situations. Good vs everything except crusher trains, can melt bosses with ease and hold the line pretty easily. I only use this build on stubbers because burst limiter override is still kind of bad unless it's with stubbers. I'm on the fence about good shootin's usefulness, you can drop good shootin for lynchpin for more survivability if you are using the gorgonum stubber instead of the achlys but honestly most teammates are going to be running all over the place. You can actually regen pretty fast while braced with steady grip so make sure to keep that in mind.

Weapon notes: 

1. Bull butcher is the general easy to use knife for hordes but it really struggles against maulers and ragers, you can throw out a special attack punch and switch weapons. With slaughterer charged up you can just light attack spam and mix in punches unless you need toughness back. The Krourk mk4 is better against everything but you need to learn it's attack pattern to use it effectively. You can swap confident strike with tenderizer for better elite damage.
2. Achlys or Gorgonum stubber? Honestly in most situations the Gorgonum is going to be more useful at practical ranges thanks to its better accuracy and higher damage but the Achlys sure is fun to shoot. I would forget about the Krourk mk5 stubber, it is the ugly middle child that is neither accurate or high dps enough to justify using over the other two.

You can really substitute any melee weapon you are most comfortable with but there is an ugly truth to the gungryn: you NEED ammo. The cleavers are the fastest move speed and you can haul some ogryn behind to secure some ammo for yourself because lets face it, almost every other match is going to have one guy autogunning everything and vacumming 90% of the ammo, it's just a fact. Don't be that guy. Exercise some fire control and save some ammo for the littl'uns. Have fun!