Random heavy trigger pull...any ideas on why?

[DAL357]

My S&W Model 64-3 has been a great gun these last few years that I've owned it. In that time I've fired close to 5,000 rounds through it without a hitch. Lately, though, it's been giving me, seemingly at random, a really heavy trigger pull once every 12-18 rounds of shooting. No, it doesn't have anything to do with overheating, as best I can tell, because it sometimes happens during dry-fire practice also. After getting through that one heavy pull, it goes back to its normal, smooth pull. I haven't narrowed it down to any one chamber it's happening with, and the ratchet doesn't appear to be worn, at least to my untrained eye.

Any ideas on troubleshooting this problem are appreciated. Thanks.

[LtDave]

Check for debris under the extractor star. Usually unburned powder is the cause.

[Sigfan26]

My S&W Model 64-3 has been a great gun these last few years that I've owned it. In that time I've fired close to 5,000 rounds through it without a hitch. Lately, though, it's been giving me, seemingly at random, a really heavy trigger pull once every 12-18 rounds of shooting. No, it doesn't have anything to do with overheating, as best I can tell, because it sometimes happens during dry-fire practice also. After getting through that one heavy pull, it goes back to its normal, smooth pull. I haven't narrowed it down to any one chamber it's happening with, and the ratchet doesn't appear to be worn, at least to my untrained eye.

Any ideas on troubleshooting this problem are appreciated. Thanks.

Check for debris under the extractor star. Usually unburned powder is the cause.

Also, make sure there isn’t excessive buildup on the front of the cylinder (that passes by the forcing cone). Had a rental Chiapa Rhino that would do that constantly


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[medmo]

First thing that comes to my mind. Have a set of feeler gauges? Check bbl/cyl gap. Excessive fouling. Also can visually check the gap putting a light on one side and your eyeballs on the other. Look for a uniform gap. Brownell’s sells a bbl/forcing cone clean kit. Notice any spitting?

[willie]

Swing out cylinder, retract cylinder latch, and then dry fire 20-30 times. If you do not observe heavy pulls, then you most likely can eliminate action problems under the side plate. But this type problem can usually be traced to three causes: extractor rod has unscrewed; debris under extractor star; or front of cylinder dragging on rear of barrel. Sometimes all can occur at same time. Check extractor rod for unscrewing. It has a left hand thread. If tightening is needed, first place empties in cylinder. Avoid loc tite.

[Tom Duffy]

First I heard of placing empties in the cylinder. How come?

[willie]

Older S&W cylinders had two small pins that passed through the extractor star. The pins held the star in place to prevent rotation. Empties take stress off them when unscrewing or tightening extractor rod, which have very fine threads and be torqued tightly. With newer cylinders, using empties may not be needed, but I suggest using them anyway. Newer cylinders' stars are shaped differently to hold stars in place.

[NEPAKevin]

The occasional high primer can also feel like an intermittent heavy trigger but wouldn't happen during dry fire.

[RevolverRob]

Check for build up in the cylinder stop notches and on the ratchet where it interacts with the hand. Sometimes build up there can cause a heavier pull, especially if you don't have momentum going between shooting strings.

The other things to check is to remove the yoke and clean the channel and yoke as well as tighten the yoke retention screw. I've had it happen before where the screw has backed out a turn or so and that causes the yoke to move back and forth, occasionally causing binding between the front of the cylinder and forcing cone.

[medmo]

Check for build up in the cylinder stop notches and on the ratchet where it interacts with the hand. Sometimes build up there can cause a heavier pull, especially if you don't have momentum going between shooting strings.

The other things to check is to remove the yoke and clean the channel and yoke as well as tighten the yoke retention screw. I've had it happen before where the screw has backed out a turn or so and that causes the yoke to move back and forth, occasionally causing binding between the front of the cylinder and forcing cone.

Thumbs up on this one. A carbon build up will cause binding on cyl rotation.