Yes, the early models (1988 and 1989) seemed to have very tight chamber dimensions. I have a 1988 (625-2) and it would only make it through about 25 rounds before it became difficult to load the next moonclip into the gun. There was absolutely no room for fouling to accumulate. 2 minutes with a finishing reamer fixed that. They are incredibly accurate guns. They also have some of the best accurte barrels S&W has ever produced. I still have a target fired in 1990 from a Ransom Rest that shows 6 rounds in one hole from 17 yards. No one at the range could believe it. If you find an early model with tight chambers any good pistolsmith can ream the chambers for you. It only takes a little tiny bit and only removes a very small amount of steel.