Yesterday I was at Cabela's (for as much as I've trashed them). In the "Library" they had a Smith & Wesson Model 745 for sale. This is a single action only model, production 5,000 units. It had the IPSC 10th anniversary logo on the side of the slide. Stainless frame, blued slide. This is a kinda rare gun but this example had quite a bit of nicking and scratching on it. It had seen some use.
That's certainly something to think about when buying a 645. Because many of them were used in competition. Me, I don't want to buy a retired competition pistol. They get fired A LOT. In the matter of the 645 design, the barrel locking lug rides along the top of the slide release as it unlocks. This is a wear point. The slide catch will wear down and get a flat on it; the matching surface of the barrel lug will incur some wear and you might see some razor blade edges on it. You can replace the slide catch; when you file off the sharp edges of the barrel lug, the wear on the face of the lug hasn't been reduced. Also, the stainless steel frame takes a hammering over time where the barrel comes to a stop under full recoil. All of this results in a looser pistol.
Another thing about a tired 645. The rear sight is subject to loosening up. It's kinda fiddly with several little parts and springs under it. Most people don't think about this, but the recoil of the slide when fired is pretty violent. The energy that is imparted to things attached to it tends to shake them up. I'm not a fan of some of the adjustable rear sights that Smith & Wesson used on their autos in this era.
When I look at a pistol like this, I want to see one that wasn't fired all that much. I'd like to be the guy who does it. Let's compare the situation to a set of golf clubs. I want to buy the set of clubs that belonged to a guy who took it up, then got tired of it after a few months and put the clubs away. That happens in every sport/activity. So look for the gun that belonged to a quitter. Or wasn't used in a shooting sport at all, if that can be determined.
That's certainly something to think about when buying a 645. Because many of them were used in competition. Me, I don't want to buy a retired competition pistol. They get fired A LOT. In the matter of the 645 design, the barrel locking lug rides along the top of the slide release as it unlocks. This is a wear point. The slide catch will wear down and get a flat on it; the matching surface of the barrel lug will incur some wear and you might see some razor blade edges on it. You can replace the slide catch; when you file off the sharp edges of the barrel lug, the wear on the face of the lug hasn't been reduced. Also, the stainless steel frame takes a hammering over time where the barrel comes to a stop under full recoil. All of this results in a looser pistol.
Another thing about a tired 645. The rear sight is subject to loosening up. It's kinda fiddly with several little parts and springs under it. Most people don't think about this, but the recoil of the slide when fired is pretty violent. The energy that is imparted to things attached to it tends to shake them up. I'm not a fan of some of the adjustable rear sights that Smith & Wesson used on their autos in this era.
When I look at a pistol like this, I want to see one that wasn't fired all that much. I'd like to be the guy who does it. Let's compare the situation to a set of golf clubs. I want to buy the set of clubs that belonged to a guy who took it up, then got tired of it after a few months and put the clubs away. That happens in every sport/activity. So look for the gun that belonged to a quitter. Or wasn't used in a shooting sport at all, if that can be determined.