MODEL 66-1 2.5 INCH THUMB LATCH POSITION CLOSED

[haifabuddy]

It sits back a bit too far when cylinder is closed, comparing appearance to other 65s and 66s. Functions ok. Is there something that need replacement in the mechanism? The rear of the cylinder is very close to the frame. Is it possible it sits back too far, thus pushing back the thumb latch release? How can I determine if it is out of specs? (I do not have gauges or tools for that purpose).

 

[Jellybean]

As long as it functions O.K., without binding or sticking, there shouldn't be a problem with it. It's position is determined by the Center pin protruding from the rear of the cylinder when closed.

Your cylinder should be real close to the frame in the back, it should have counterbored cylinders so the cartridge rims sit down inside the cylinder. If your other 65s and 66s are newer than about 1982 they should look different as this feature was dropped about that time. After the change the cartridge rims sit outside the cylinder and can be seen from the side with the cylinder closed.

 

[haifabuddy]

Thanks. The center pin does seem to stick out more than others I have. I know the rear of the cylinder in a P/R gun sits closer to rear of frame than newer others, as my 66-1 but I was thinking there is a spring that has become weakened allowing the center pin to more easily push back the thumb latch. My concern is that the thumb latch should not sit so far back and this could be a sign of future trouble.

 

[Jellybean]

I see. Your thumbpiece is attached to the bolt, which does have a spring at the back of it. With the cylinder closed check to see how much wobble you can feel in the thumbpiece. If you can easily push it back further there may be a problem. Keep in mind this isn't a very heavy spring and it won't take a whole lot to move it. You're just looking for resistance more or less. There might be some up and down wobble in the thumbpiece which is normal.

With the cylinder open, look at the breech face where the cylinder pin enters the frame and you should see the front of the bolt sitting flush with the frame. Pull back on the thumbpiece a couple of times and let it go, if it returns to the flush position without hesitation it should be O.K.

 

[haifabuddy]

Passes all the tests you advised. Comparing to other 66s (-2) and 65s (-2 and -3), however, I think the bolt spring is a bit weaker than others. Maybe this is something peculiar to the 66-1. I am going to add this part to my spare kit.

Thanks again. Now I know no need (or excuse for PC work) to send to SW.

Ordering bolt plunger spring spares. Is that correct?

 

[Jellybean]

Without looking up all the part numbers I would say there wasn't any difference between the models you listed. However that doesn't mean your spring isn't weakened a little.

The springs part description is "Bolt Plunger Spring" and Smith and Wessons part number should be 070200000

 

[haifabuddy]

Thanks, that's the part # I picked out. When I call I will ask if that spring can weaken in a 40 year old gun which is not shot much.