Will 500cc implants under the muscle look small?

The implant selection should be based on a combination of your desired size, soft tissue dynamics, breast base diameter and skin elasticity.  I recommend an in-office examination as well as a detailed discussion with a surgeon who you are comfortable with.   Finally, make sure your surgeon is a Double-Board Certified Plastic Surgeon certified by the American Board of Plastic Surgery (ABPS), a member of the American Society of Plastic Surgery (ASPS) and the American Society of Aesthetic Plastic Surgery (ASAPS).Best,Dr. DesaiBeverly Hills Institute for Aesthetic Plastic SurgeryHarvard Educated, Beverly Hills & Miami Beach Trained, Double-Board Certified Plastic Surgeon

I routinely perform a 3-d simulation for all of my breast augmentation patients in order to properly assess and size each patient so they are ultimately happy with their final size and profile. 

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  500 and 600cc implants are large implants.  Pictures would be very helpful in making this decision.  The size, profile, and shape of
the implant is based on your desired breast size/shape, your chest wall
measurements, and soft tissue quality.  This decision should
be based on a detailed discussion with equal input from both you
and your surgeon.   
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

Dear Meganjimenez,determining the ideal breast size and matching that goal for the patient is the most difficult part of breast augmentation. It starts and ends with the patient. We have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements. Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If its too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match. Of all of my breast augmentation patients, everyone of them have been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small. You should spend some time discussing it with your plastic surgeon.Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery 
Member, Am. Society of Plastic Surgery

It is difficult to counsel you without an exam, photos or measurements of your chest wall and breast configuration.We use surgical simulation software in our office to take a lot of this kind of guesswork out. Did you use a sizer in the office? How did you and your surgeon arrive at the implant size? Was it just exam and conversation or did you use any other objective method like the above to narrow the search?