They are very close. A Model 10 speedloader will work nicely with a Colt DS. The cylinder diameters are pretty darn close but the frame is slightly smaller and of course the exact dimensions are a bit different. I have a couple of boxes of holsters. One of them will hold both PRETTY WELL but only one out of about six. Unless you are very casual about what you consider to be an acceptable fit my guess is NO. For what my guess might be worth to you.