I have a 3D profile plane and it snaps out of an inside loop very easily, but does not snap out of an outside loop. The outside loop is very tight compared to inside loop.
Thanks in advance!

Are you carrying a lot of aileron or rudder trim?

Oh your good! Yes, right aileron trim is more than it should be....
Why would that be causing it?

Snap roll is a combination of aileron, elevator and rudder. You give hard elevator to make a loop and you have aileron trim then the plane will appear to snap.

Use less elevator or fix your ailerons to get rid of trim.

Try flying on a sim and do a loop and bury the right stick to a corner and I bet you will see a similar situation.

K. Cannon nailed it. Excessive aileron trim will induce unwanted results. If that trim is necessary to fly basic straight and level because of probable warps, you can minimize the effect by setting up for what is known as "True Neutral". I found this a few years ago in a Model Airplane News Flight Technique article "Intro to 3D Flying". Author Dave Scott explains the procedure. Or, keep backing off elevator travel till you get a reasonable loop as mentioned.
Fly low...Fly safe