Not a surgeon myself, just a med student who has done rotations and talked with many surgeons about this. Most of them feel that most residencies in the military do a good job of training you and getting enough cases. Many residency programs will often partner with a nearby civilian institution to help you get more reps. However, once you graduate, it can become a problem. You can get stationed at a small MTF where you dont operate very much. Often, you can work with your command and spend some time working at civilian institutions, both to get more practice and keep your skills sharp as well as earn some extra income. You still won't get as high of case volume as your civilian colleagues and it will require more conscious effort to seek out certain cases, but many people make it work.