I picked up the 66-1 at a local Gunshow. After firing it with some magnums the cases were a problem to get out. I noticed the primer strikes appeared inverted. I posted about it and got a number of reasons why it may have occurred. One was the strain screw was not all the way In. Have been around guns a long time and have never seen this issue from that but was likely shooting 38's. I tightened the screw and finally got a chance to bust a few caps. Works fine. Thanks to whoever made the suggestion,
JR

Were these reloads or factory loads? I've never seen any fired inverted primer strikes. I've seen them nearly flat with excessive pressure loadings. If you reload, you might try using small rifle primers to see if that makes a difference if it occurs again. I use small rifle primers in my .38 Super , .38 Special, and .357 Magnum loads, and they work fine.

At one time, I had a Llama .38 Special revolver which had a disturbing habit of the primer blowing out at the firing pin area (i.e., a round hole where the firing pin depression should be), and resulting gas leakage. I never figured out why, but it didn't happen when small rifle primers were used. I didn't keep the Llama very long after this discovery.

These are Remington 125 Factory. When I asked about it I was told on here the recoil was pushing the hammer back blowing the primer into the firing pin hole. After tightening the strain screw as the person suggested it stopped.
JR.

I never heard of that before. But it does make sense to me. thanks for posting this up; will keep it in mind if I ever see that situation in the future.

Some people think the strain screw is for lightning the trigger pull. I've seen people shorten them and back them off. Problems arise sooner or later.

I guess the reason I never saw it when I taught LE firearms is we usually shot Wadcutters and at the most +P. It makes sense as I was watching some screen captures off a friends video he was showing the fire and recoil. I told hin that he faked it because the hammer was back on a number of shots to some degree. I knew he would never do that and now it's clear that the hammer can be pushed back with a 357 load. His didn't have issues with the primer though.
JR

That is very similar to the condition that resulted in the 686/586 recall back in the 80's. A enlarged hammer nose bushing. You may want to contact S&W and see if there was ever a "soft" recall on the 66 for that same reason.

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H Richard
SWCA1967 SWHF244

I heard a loose strain screw can cause light strikes, but in this case I think it was barely on the edge of a light strike. With the earlier lockup recall the primers had flowed back around the firing pin. Here it looks like the hammer just hit enough to detonate the primer which then pushed the firing pin back.

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"He was kinda funny lookin'"

I believe you are correct. That's what I was told by someone on here before I tightened the screw. After tightening the issue went away.
JR