+3.5-5% Strength for 3.5s on Hit. Stacks 5 times.
+25-40% Cleave on Hit. Stacks 5 times.
+10% Critical Chance for every 0.2-0.35 second while aiming. Stacks 10 times. Discharges all stacks upon firing.
You can Hipfire with this weapon while Sprinting. +6-15% Close Damage while Sprinting. Also reduces weapon spread at all times by 30%.
Point-Blank Barrage is very fun and very strong, but it tends to be an ammo blackhole. Using it in quickplay is less consistent than going for full melee focus with Heavy Hitter.
You can use any grenade, they are all fine it's up to personal preference.
Either Bullrush or Taunt (With Valuable Distraction), both can work.
Only Bonebreaker is really viable for melee, Ogryn boys don't get much flexibility with their auras.
Heavy Hitter is just superior to Feel No Pain, the latter adds a lot of tankiness and lets you shrug off hits a lot more, but in maelstrom ideally you can survive without that much damage reduction and the bonus damage for heavy attacks lets you get rid of the massive number of enemies much quicker and that tends to have more consistent results for success.
Karsolas is my most comfortable pick as it can deal with hordes extremely well, and also clear out carapace relatively easily, but pretty much any Ogryn melee can do the job. Shovels, bully clubs, cleavers, even slab shield does a lot of damage and is not really a "tank" melee. Go for your most comfortable melee, but keep in mind you'll want to be using your heavies most of the time.
Same thing with ranged weapons, I like the Kickback for its range but you can also use Rumbler, Grenade Gauntlet, or Ripper Gun (Mk V tends to be best and should be used unbraced for best effect). For the Heavy stubber you'll probably want the Gorgonum as it's more efficient and has better range than the Achlys when you're not using Gunlugger build.
You either go full health or full toughness. I like full health for being able to tank a couple of stray hits and surviving on low health tends to be easier for you than other classes so you can let quickplay teammates take medicae stations if there aren't enough for everyone. Also synergizes well with Too Stubborn to Die.
For perks I like the standard CDR and stamina regen, and for Ogryn specifically it feels like they benefit more from toughness regen speed, you tend to eat a lot of stray shooter salvos and it can eat through your toughness quickly, and so with Lynchpin, having quicker coherency toughness can really be felt as long as you stick to the team most of the time.