How many CC's do you lose when going under the muscle?

 Thank you for the question. In my opinion, it is not possible to accurately determine how many CCs the you would “lose” when undergoing sub muscular breast augmentation surgery.  I would suggest that you do not make your decisions based on statement such as: “you will lose 50 cc of volume when breast implants are placed under the muscle”. These statements are simply not reliable enough to utilize clinically. Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work. Sometimes, it is necessary to seek several consultations before you feel comfortable about your choice.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "large C or small D cup” etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate. Again, best not to discuss your goals and/or judge the outcome of the procedure performed based on achieving a specific cup size.  The use of computer imaging may be very helpful during the communication process. The use of  in bra sizers may also be helpful. In other words, use as many “visual aids” as possible during the communication process. I encourage patients to meet  with me as my times as necessary, to feel comfortable that we are both on the “same page”.
 
3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery. I generally select appropriate breast implant size/profile after the use of temporary intraoperative sizers and viewing the patient's chest in the upright and supine positions.
I hope this (and the attached link,  dedicated to breast augmentation surgery concerns) helps.  Best wishes.

There is an imperceptible loss of projection
approximately 1 cm and volume following subpectoral breast augmentation. This would clearly depend on the thickness of
the pectoral muscle

No one will be able to predict your cup size, because there is no standard bra sizing among different manufacturers.  You should re-visit with your surgeon to look at before and after photos of patients who look like you, try on sizers, do the "rice test,"  and avail yourself of all options to know what it may look like to have 500 or 550 ccs.  Your surgeon will be the best guide, so go back one more time for final questions. Click on the link below to see a breast augmentation that is fully healed.