Axton isn’t Krieg so he doesn’t need to stack health. I’d stick with the extra grenades, especially if you’re throwing them around like so many fun-sized candies.
What gear are you using? An Ogre has good splash damage and can be a beast in Axton’s hands.
As for your skill, I say it looks good, but you can probably get rid of grenadier with the BBB and relic. I’ll leave that up to the experts, though. Speaking of which, @johnrr6 and @Afro_Samurai, what do you guys think?
I was thinking
Hornet/DPUH
Ogre/kerblaster
SWORDSPLOSION
Topneaa
Those should work just fine with that build.
So then this?
http://bl2skills.com/commando.html#55055152015005515010005050140100
Should give me 20 nades to play with
@BTK420247 The spec you posted looks solid. The +4 grenade Stockpile relic and BBB are really only optimal for a pure grenade build, but not for splash overall… But pure grenades is a super fun challenge! IF you were to go that route I suggest:
-Fastball
-Explosive relic
-Corrosive, Fire, Shock BoTA
-Blue Expert Grenadier with +6 to Steady, +5 to Grenadier
As far as an overall splash / explosive damage build, try using the explosive relic with your favorite explosive weapons. A great one to try is the Swordsplosion. And a shield to alternate when survival is more important would be the Antagonist or the Blockade. Both are very tanky on Axton since he has quite a few shield buffs. If you are running an explosive Axton, I also recommend:
-DPUH
-Baddaboom
-Ravager
-Ogre
-Legendary Soldier
-Legendary Engineer
-Blue Expert Grenadier with +6 Steady, +5 Impact
-Purple Expert Grenadier with +5 Steady, +4 Impact, +4 Grenadier
With that Purple Grenadier and Stockpile Relic you will have 23 grenades which is a TON.
And if you want to abuse grenades, Grenadier is the way to go.
Realize that meteor showers have some limitations though. They aren’t good close up and will kill you quick. And you may want to cosnsider switching out the stockpile for an explosive damage or bone relic. 4 extra grenades may not be worth the loss in damage or cool down.
That will work well with Fastballs and get a DLC 4 grenade to regen grenades. Or use BBB. Weapons choice looks good. Try a Little Evire or Thunderball Fists for shock. The trouble with the Grenadier is that it is an OFFENSIVE mod and is not nearly as good as the Soldier in the defensive mode. You simply CANNOT be defensive minded with a Grenadier.
I forgot to mention that there are other weapons that are NOT explosive that get grenade damage buffs. The two I know of and use most often are:
-Blockhead. I use a Fire BotA with that one.
-Twister. Shock BotA on that one.
-Hornet. Super great for killing loaders, I use it with a Corrosive BotA.
-Pimpernell. I have one in fire, shock, and corrosive. Use the bones with this one.
All great suggestions so thanks for that. I’ll play around with a few different things this weekend and see what I land on.
No twister never got reaper on the splash, after the patch when people including myself said the twister got reaper again we were talking about on the bullet.
For around a year the twister got no reaper at all, not even on the bullet.
No mention of me 
Nah not really lol
You said you were taking a break. 
I said I got back into bl2 a few days ago.
Oh right, you did…congratulations? 
Just kidding. 
Since you’re here, Pimp, any advice for the OP?
You’re lucky I like you. Lol.
To the op the build looks good. I personally always want resourceful in my explosive builds because of battlefront. I would suggest a grog so you can heal off your grenades tho I’m sure someone already said that.
So after about a week of tinkering and killing of come to a conclusion. I F*****g love the SWORDSPLOSION.
I ended up settling on this build.
http://bl2skills.com/commando.html#55055152015005515010005050140100
Later when I have more time I’m going to go thru the master build list for Axton and see if it matches any, I hope not, I’d like to do a kinda write up about my time with the SWORDSPLOSION.
It’s a great shotgun provided you remember not to use it up close… 
That’s part of its charm. If you haven’t killed yourself multiple times in a single Swordsplosion session you’re not worthy of the gun.
Some of us like staying on our feet, Hattie. 
Wait…what am I saying? This is Krieg we’re talking about. 
Yes, how’s that permadeath Krieg run going