Does the 115% bonus rad damage while gamma burst is active anointment stay working if i swap weapons and then back to the gun with the anointment? or is it like 200% bonus damage while action skill is active where you instantly lose the bonus when you swap weapon?
Also i guess is it 100% essential to run either a frontloader or deathless with gamma fl4k or is this anointment just as good of an option?
The Gamma anoint works when swapping AFAIK.
The 150 Rad under 50 anoint will deal more damage, but to make it permanent you have to run either Front Loader or Deathless; with Fl4k this makes you very fragile because you lose health-gate.
I personally run GB without 150 under 50. It works fine and with good gear can clear any content in the game. Nevertheless it is true that the theoretical DPS potential isn’t as good as RA or FA.
It’s good in that Gamma doesn’t have many viable anoint options, and can be swapped back and forth, but 50/150 is more powerful. Not just in total weapon damage, but in that it boost all damage, like grenades and even the initial burst of Gamma Burst, and stays active at all times. The catch is you need Front Loader or Deathless though. The Gamma is far more limited, but it still can get the job done and gives more shield and artifact flexibility.
Personally I run both, cause drops can be a bitch. So it’s nice to have more 2 anoints you can work with.
im mostly asking as its the only anointment i get 
would be nice having a use. literally 75% of weapons i get have that anointment would be nice them having a use lol.
I personally prefer Gamma anoint over the Urad.
Health gate is pretty important to me because despite what GBX says, you take so much more damage in M10. Without health gate you go down a lot.
On top of that, damage advantage URad setup has over Gamma setup is overrated because you either have to give up an offensive shield like Old God, or the Pearl.
But if you really want to run URad, I strongly recommend speccing into Lick the Wounds.
The problem with damage in M10 with Urad is the damage from splash damage and environmental damage.
I have been running a Urad/Deathless build and the damage increase over Gamma is substantial. However a stray barrel or enemy with a launcher can quickly put you in FFYL.