Very quick way to do this , in the second section with Jeffery called Mountain Highs.
Go into the Trials section (you have to beat all the normal levels first) and choose Trial#9.
Here you will have 3 boulder shots, and 2 rings of orange pegs , approx 70 of them.
Aim on the left side of the rings and shoot, you should have no problem getting 50+ in 3 shots.
Now if going for this achievement specifically here don't clear all the pegs as this will finish the level and add to the amount of time needed with the end extreme fever sequence and reloading the level, what you are looking for to move it along faster is just to keep re-trying the level.