Model 28-2: Off Center Firing Pin?

[mainegrw]

So I took my newly acquired 28-2 to the range today to shoot it for the first time. This gun was made in either late 68 or early 69, and is in primo shape. The action is perfectly tight with no play or endshake in the cylinder at all. The lock up feels akin to a Colt Trooper of that vintage actually.

What piqued my curiosity however, was that I was getting off center strikes on the primers, and even had a couple shots that didn't ignite on the first try. When I noticed it, I stopped and inspected the gun, but everything looks and feels right, no signs of it being out of time, no lead spatter, or bits of jacket on the bench (was shooting JFPs today), and every shot was hitting right where I was aiming. So I'm reasonably certain I dont have a timing issue at all.

Now that I have it home, I did a further inspection, and I believe what I'm seeing is that the firing pin hole is not centered on the bore, but rather slightly off to the right side of the gun. I worked the action while shining a flashlight in the gap between the cylinder and the breechface, and this seems to be the issue. I shined the light from both sides to make sure that it wasn't an illusion caused by shadows, and it appears the same to me no matter the light's direction. The off center hole also matches the striking on the primers shown below.

What I'm curious is, how common is this, and is it something to be concerned about? What also would be the fix if it is something requing repair?

Any thoughts are greatly appreciated, thanks!

EDIT: manged to get a good picture of what I'm seeing down the bore.



Sent from my SM-N976V using Tapatalk

[tenntex32]

Have a local gunsmith check barrel/cylinder/firing pin alignment with a range rod.

Then go from there. Something is definitely amiss and may be due to a bent yoke, improper carry-up, timing, etc.......

I have yet to see one quite that bad and if it is causing misfires then it definitely warrants further investigation.

I guess it's not out of the realm of impossibility for the firing pin hole to be that far off center but it seems a bit odd to me. I would think some other issue is at play.

[mainegrw]

Originally Posted by tenntex32

Have a local gunsmith check barrel/cylinder/firing pin alignment with a range rod.



Then go from there. Something is definitely amiss and may be due to a bent yoke, improper carry-up, timing, etc.......



I have yet to see one quite that bad and if it is causing misfires then it definitely warrants further investigation.



I guess it's not out of the realm of impossibility for the firing pin hole to be that far off center but it seems a bit odd to me. I would think some other issue is at play.

Will look into it... im just surprised, like I said, she shoots nice and straight, and the timing seems right on. The rear sight is set dead center too. If the frame were bent, I'd expect that I'd need to compensate windage-wise a bit. Idk..

Edit: Also, I should mention, the light strikes might be a separate issue. The trigger feels suspiciously light compared to other 28s and 27s I've had, so I think maybe the main spring is ready for rpelacement...

Sent from my SM-N976V using Tapatalk

[Golphin]

I was going to say I think those strikes in the pictures would set off primers. Many put spring kits in the revolvers and that can very well cause light strikes. Also make sure the screw is tight on the spring.

[tenntex32]

Maybe one of the S&W gunsmithing gurus can tell us what the allowable spec is for offset primer strikes.

While I have observed slightly offset primer strikes with some examples the OP's firing pin indentations seem a bit more off center than I would typically expect, but in all fairness it is a small (diameter) pistol primer caliber.

Now if it were a large pistol primer caliber and it was that far offset I would really be concerned, especially since you can get some larger caliber ammo that would typically have large pistol primers that actually has small pistol primers. (My M1917 revolvers in .45acp come to mind as I have used some .45acp ammo that had small pistol primers instead of the typical large pistol primers.)

[mainegrw]

Originally Posted by Golphin

I was going to say I think those strikes in the pictures would set off primers. Many put spring kits in the revolvers and that can very well cause light strikes. Also make sure the screw is tight on the spring.

It's nice and tight, and it doesn't look like anyone took a file to it either. Was thinking maybe it's a reduced power spring, however it does not appear that the side plate was ever removed. If it was, at least it was done right. Every screw on this gun except the grip screw, and strain screw looks untouched by screw drivers.

Really, I dont believe this gun was shot much at all. It was for sure, when I bought it, there was lead residue in all of the chambers and the bore, the cylinder has a turn line, and someone took the time to replace the magna grips with Pachmayrs. I really wish I knew how much.

What I do know is that it came out of a local collection along with some other neat pieces I've grabbed recently. The seller is down-sizing, and selling off his stuff a few at a time. Out of it, I grabbed a 1947 K22, this model 28-2, a 38 M&P model of 1902, and possibly a 38/44 HD (not sure if this one was part of the collection or not). The latter two were in tough shape, shootable, but not really to my liking, so they were traded for other guns. The guy also collected antique Colts, and High Standard stuff too. There were boxed examples of many HS target pistols, and at least one of every version of the Colt Woodsman that caught my eye among others.

Sent from my SM-N976V using Tapatalk

[tenntex32]

Originally Posted by mainegrw

It's nice and tight, and it doesn't look like anyone took a file to it either. Was thinking maybe it's a reduced power spring, however it does not appear that the side plate was ever removed. If it was, at least it was done right. Every screw on this gun except the grip screw, and strain screw looks untouched by screw drivers.

Really, I dont believe this gun was shot much at all. It was for sure, when I bought it, there was lead residue in all of the chambers and the bore, the cylinder has a turn line, and someone took the time to replace the magna grips with Pachmayrs. I really wish I knew how much.

What I do know is that it came out of a local collection along with some other neat pieces I've grabbed recently. The seller is down-sizing, and selling off his stuff a few at a time. Out of it, I grabbed a 1947 K22, this model 28-2, a 38 M&P model of 1902, and possibly a 38/44 HD (not sure if this one was part of the collection or not). The latter two were in tough shape, shootable, but not really to my liking, so they were traded for other guns. The guy also collected antique Colts, and High Standard stuff too. There were boxed examples of many HS target pistols, and at least one of every version of the Colt Woodsman that caught my eye among others.

Sent from my SM-N976V using Tapatalk

Here's a quick way to test/fix your mainspring strain screw if you think reliable primer ignition may benefit it being a tad longer.

Knock out a fired primer from a case. Remove the small anvil in the primer cup. Take a small flat tipped punch and flatten out the firing pin indentation. Back off the strain screw enough to place the primer cupped over the end of the strain screw and then tighten the strain screw down.

If it ignites primers reliably and doesn't create an excess amount of trigger pull weight you can simply leave it in place. If it does create an excess amount of trigger pull weight you can adjust the screw back out slightly to see if there is a sweet spot somewhere before it once again becomes unreliable.

If you find you still need more than the primer cup's material thickness for reliable ignition you can always add a shim in the bottom of the primer cup without worry of it coming out once everything is screwed back down.

It might be a simple way to diagnose (and possibly fixing) the problem before buying another strain screw.

[Hondo44]

Originally Posted by mainegrw

I did a further inspection, and I believe what I'm seeing is that the firing pin hole is not centered on the bore, but rather slightly off to the right side of the gun.
What I'm curious is, how common is this, and is it something to be concerned about? What also would be the fix if it is something requing repair?

Any thoughts are greatly appreciated, thanks!

I agree with your findings.

I would further troubleshoot the isuue in the following ways:

With cyl open, pull back on thumb latch so you can pull the trigger, drop the hammer but do not release the trigger to keep the pin in the bushing hole.

Is the pin crowding the left side of the hole?

Now cock the hammer and inspect the pin.

Are there rub marks, burrs or gouges on the left side of the pin and does it look slightly tweaked to the right?


Suggestions if you find the above evidence:

1. If you can track down the few misfires to another cause, do nothing.

2. Use a small needle file to slightly relieve the left side of the hole in the bushing. Smooth the burrs on the pin and/or straighten/replace if bent. Test for centered firing pin strikes.

3. Return to S&W or take to a S&W knowledgeable gunsmith to repair/ replace bushing.

My recommendation is to start with #2 above.

[Abbynormal]

Were the rounds reloads or factory? When was the last time it was cleaned? I've seen off set firing pin imprints in a lot of Smiths and never had a problem.

[mainegrw]

Originally Posted by Abbynormal

Were the rounds reloads or factory? When was the last time it was cleaned? I've seen off set firing pin imprints in a lot of Smiths and never had a problem.

They were Winchester factory loads, and the gun was freshly cleaned last weekend, and was treated to a coat of Rennaisance Wax to boot. No crud build-up problems here.

Sent from my SM-N976V using Tapatalk

[mainegrw]

Originally Posted by Hondo44

I agree with your findings.



I would further troubleshoot the isuue in the following ways:



With cyl open, pull back on thumb latch so you can pull the trigger, drop the hammer but do not release the trigger to keep the pin in the bushing hole.



Is the pin crowding the left side of the hole?



Now cock the hammer and inspect the pin.



Are there rub marks, burrs or gouges on the left side of the pin and does it look slightly tweaked to the right?





Suggestions if you find the above evidence:



1. If you can track down the few misfires to another cause, do nothing.



2. Use a small needle file to slightly relieve the left side of the hole in the bushing. Smooth the burrs on the pin and/or straighten/replace if bent. Test for centered firing pin strikes.



3. Return to S&W or take to a S&W knowledgeable gunsmith to repair/ replace bushing.



My recommendation is to start with #2 above.

Thank you for the tips, will definitely check these things, however I don't recall seeing any unusual wear on the firing pin when I cleaned and waxed the gun last week. I will give it more scrutiny though.

Everything seems to run nice and smooth, and right, that's why I was surprised to see the off center strikes. I do really believe the light strikes were unrelated, as I've had that problem before with a Pre-27. It was easier to chase down with the Pre-27, as it was fitted with a Wolff reduced power spring, which has a ridge down the middle, and is quite readily identifiable by sight. This one seems to have a S&W stock spring, and its not striking as lightly as the Pre-27 did.

Sent from my SM-N976V using Tapatalk

[6string]

I've seen this before. The hand is pushing the cylinder counterclockwise upon the moment of lock up and discharge.
Have a look at the fit of the crane to frame. The tightness or looseness may be different depending on whether the hammer is cocked or not. The hand, upon lock-up, pushes on the cylinder in the same direction it opens.
Sometimes, the front lock-up piece that locks into the front of the ejector rod is not as tight as it could be.
Maybe an oversized hand was installed?
Often, people think that's the main culprit regarding lock-up issues.
Personally, I think it's preferable to have a bit of play in the cylinder rather than the cylinder is firmly locked up but out of alignment.

[mainegrw]

The plot thickens... in an attempt to stiffen up the mainspring, I tried the suggested trick with the primer cup over the screw tip. Turns out, it's not necessary, as backing the screw all the way out, and reinserting it, allowed the screw to set deeper. I had to pull the side plate off to diagnose the following described problem, so I replaced the spring with another one I had in my spare parts box as well.

Unfortunately, another issue popped up now: in single action, when the hammer drops it pulls the trigger forward with it. Trying to observe the issue with the sideplaye off yields no discernable problem, as it doesn't happen with the side plate off. Any idea what could cause that? Everything runs fine in DA, this seems to be a problem with SA only. I dont see any signs of part modifications or anything, no polishing or anything. I just dont know what to make of it...

Sent from my SM-N976V using Tapatalk

[tenntex32]

Originally Posted by mainegrw

Unfortunately, another issue popped up now: in single action, when the hammer drops it pulls the trigger forward with it. Trying to observe the issue with the sideplaye off yields no discernable problem, as it doesn't happen with the side plate off. Any idea what could cause that? Everything runs fine in DA, this seems to be a problem with SA only. I dont see any signs of part modifications or anything, no polishing or anything. I just dont know what to make of it...

Sent from my SM-N976V using Tapatalk

Here's a pic of a 28-2 of mine with the sideplate off (hammer down) that I just took for another thread. The sliding bar hammer block is shown in the full up position as it would be when fully assembled and the hammer down.

Have a look at your 28-2 and see if you see anything different.

Let me know if you need me to take a pic of it with the sideplate off and the hammer cocked.

(The only thing I can come up with if it isn't doing it with the sideplate off is that there is something wonky with regards to the sliding bar hammer block when you screw the sideplate down. Other than that we would need to see good quality pics of it with the sideplate off.)

HTH,
Dale

[Muley Gil]

"Let me know if you need me to take a pic of it with the sideplate off and the hammer cocked."

Try to avoid working the action with the sideplate off and the mainspring attached to the hammer. The hammer pin isn't supported on both ends and has been known to snap off.

[tenntex32]

I'll try not to do it a bunch if that makes you feel better.

Of course I typically just back the strain screw out and don't dilly-dally if I all I need is a quick pic.

That being said if anyone is prone to doing so often please heed Muley's advice.