Trigger return binding on Model 28 with 14 lb. rebound spring

[AEM]

I have a Model 28-2 that I am sure was in factory condition until tonight. I am pretty sure it has never been fired. I did a light action smoothing and installed a Wolff Power Rib mainspring and a 14 lb. rebound spring. The 14 lb. spring is the middle-of-the-road spring in the Wolff set, which ranges from 13 to15 lbs.

I have done this action job on several J and K frame Smiths, but never an N frame. I take my time and follow directions. I am especially careful to polish the frame where the rebound spring slides, the bottom and interior side of the rebound slide and the hole in which the rebound spring rests. I polished the inside of the hole with 600 grit sandpaper on a small dowel chucked in my Dremel tool. I lubricated the rebound slide, inside and out, with a high quality lube, not a grease.

Upon reassembly, it functioned fine with the sideplate off, but when I replaced the sideplate and carefully tightened the screws, the trigger would sometimes fail to return fully in both single action and double action. It would bind up about halfway through the return and require a nudge to get it to return completely.

It seemed like any tightening of the sideplate screws or even firm pressure on the sideplate with my fingers could get it to bind up. I disassembled and reassembled several times, making sure all was installed correctly and there was nothing binding the action. I couldn't cure the problem that way, so I re-installed the factory rebound spring. That corrected it and it functions fine now, but the trigger pull is still way too heavy. It is almost as heavy as before.

I once sent a Model 27 off to a very highly regarded gunsmith in the Northeast who is renowned for his work on Smiths. It came back with this same problem. He took it back and returned it working fine, but with a significantly heavier trigger pull. That makes me wonder if the N frame can't tolerate a spring lighter than the factory rebound spring. I have the 15 lb. Wolff spring and am tempted to try it, but am too tired and frustrated right now.

Any suggestions whether I made a mistake in the action job or whether it was just the 14 lb rebound spring will be much appreciated!

 

[scooter123]

First, it will be very helpful to load that model 28 up with snap caps and dry fire it until you shoot the rim off of one of those snap caps. That should take about 6 to 8 thousand trigger pulls and will put some wear marks into the frame recess or sideplate.

From your description I suspect that what you have is a binding trigger and you'll need wear marks to identify the area of the bind and how to address it. I had this issue on my model 620 only in my case it was causing a "hitch" in the trigger pull just before the sear released. Making up a 0.0015 inch shim and shimming the trigger away from the frame recess provided a complete solution. Yeah, I could have hand stoned the trigger, however MIM triggers are quite hard and I'd probably still be stoning it because 0.0015 inch on hard steel by hand is freaking huge. Using hardened shim stock was an expedient method that will likely last longer than I'll be alive.

 

[tomcatt51]

it functioned fine with the sideplate off, but when I replaced the sideplate and carefully tightened the screws, the trigger would sometimes fail to return fully in both single action and double action.
It seemed like any tightening of the sideplate screws or even firm pressure on the sideplate with my fingers could get it to bind up.

First, it's very hard on the frame studs cycling the action with the sideplate off.

That said, it sounds like you have a side clearance issue. Put the side plate on with just the trigger and hammer installed. No rebound slide or springs etc. Tighten the sideplate and see if either drags. They should effortlessly flop back and forth. If they don't, find out why. A common cause is one the cross pins protruding slighty.

If that's not it start adding internals one at a time until you find what does drag. It will be easier to feel if you DON'T install the rebound or mainspring. You're not testing for function, you're feeling for drag.

 

[Rule3]

I have the 14 lb spring in several N frames. I do not know why you dremeled the rebound spring slide hole? but suspect you may have messed something up in there like made it too large. Can't tell without looking at it. You sure the hammer block bar is installed correctly?

 

[jimmyj]

Possible the problem is the safety bar

 

[tomcatt51]

Possible the problem is the safety bar

Possible. I fix that by keeping the hammer blocks in a zip-lock bag.

 

[AEM]

Thanks for all the helpful suggestions!

I suspect the hammer block as well. What position should it be in when I close up the sideplate?

I polish the hole in the rebound slide with 600 grit emery paper because it always has machining marks in there and I have read that if you put in a lighter rebound spring you should smooth out the hole to prevent binding of the spring, which may not be present with a full strength rebound spring.

I will get back at it armed with these tips. Thanks again.

 

[jimmyj]

IIRC-the safety bar should be in the low position (hammer and trigger in normal position).
Also make sure the safety bar opening is on the correct stud (the tit on the rebound spring housing)

 

[tomcatt51]

What position should it be in when I close up the sideplate?

With the trigger forward, the hammer block is all the way up. It's up "blocking" the hammer so if can't be forced foward to fire the gun.

It's a redundant part. They were added (late 40's?) after a gun was dropped from something like 60 ft onto the steel deck of a ship and it landed on the hammer spur in such a way the hammer was forced forward firing the gun. You have to actually bend/break parts for this to happen even without the hammer block.

 

[Rule3]

What Jimmy said above^^

I put the bar all the way up to the top and the top of the pin on the rebound slide. It's pretty hard to put the side plate on if the bar is not correct.

I just found something interesting on a old 5 screw pre M 10 as I was cleaning it out I sprayed some compressed air to dry out the solvent and found a tiny pin. Turns out it was the rebound slide stud. I have never seen one that came out. Just dumb luck I saw it and it did not fly to some area of the garage never to be found.

The bar should always be put back in. It does not add to the trigger pull and makes a much safer revolver should it ever be dropped.

 

[scooter123]

It's a redundant part. They were added (late 40's?) after a gun was dropped from something like 60 ft onto the steel deck of a ship and it landed on the hammer spur in such a way the hammer was forced forward firing the gun. You have to actually bend/break parts for this to happen even without the hammer block.

The reports I've read concerning this incident indicate that the Lieutenant who dropped that Victory model was the person who was killed by the resulting discharge. It's also implied that the gun was dropped on a steel deck from waist height, not 60 feet. In fact I've never seen one report that specifically stated the height of the drop, if you have a link to the original Naval report please post it.

The hammer block was a direct result of this incident and I personally feel that it's unwise and unsafe to remove it. This device has absolutely NO detectable effect on trigger feel and at most it's only negative is the subdued "rattle" it introduces into the lock work.

 

[tomcatt51]

The reports I've read concerning this incident indicate that the Lieutenant who dropped that Victory model was the person who was killed by the resulting discharge. It's also implied that the gun was dropped on a steel deck from waist height... if you have a link to the original Naval report please post it.

My understanding was that a sailor was killed by the "AD" of a Victory model dropped from considerable height onto a steel deck. As a result the Navy requested Colts but Colt couldn't meet production quotas so they went back to S&Ws after S&W added the current version hammer block.

The earlier Victory models (starting in 1905?) did have a hammer block but unlesss kept clean it was prone to jam with crud rendering the block in-operative.

You can show otherwise? If you have a link to the original Naval report please post it.

It is clear a S&W revolver dropped on the hammer spur has to bend/break parts (the rebound slide holds the hammer back with the trigger forward) for the hammer to move forward.

 

[scooter123]

The current hammer block was definitely post WWII, my recollection is it was 1947 but that isn't a memory I would put money on, might have been 1948. So, there wasn't any resumption of production due to the new design, that was done to insure a higher degree of drop safety for the emerging civilian market.

I'm also under the impression that prior to this design the only drop safety feature was the rebounding hammer that is driven by the rebound slide. I've also seen reports in the internet that the hammer pivot pin failed on that single fatality and this allowed the hammer to pivot forward of the rebound slide and contact the primer. As we both know hammer pivot pins can and have failed on occasion from just simple use. So, it's not much of a stretch to conclude that this particular failure may have some of the cause being poor metallurgy in the pivot pin. Basically, without the help on a Naval Historian about the only thing we can say safely is that "stuff happens".

What I do know for sure is that the current hammer block is about as impervious to "stuff happens" as I think is possible. Basically, it's a very elegant, simple, and effective solution to the issue of providing a drop safety in the event of a failure of the pivot pin. Since I'm already well down the path of Hearing Impaired that slight rattle doesn't bother me a bit and I don't see any reason not to use this very clever bit of design.

 

[tomcatt51]

Suit yourself, we can dis-agree. IMHO the hammer block is redundant but then my only revolvers with hammer spurs are 17/617's.

On my "useless list" the hammer block ranks below magazine disconnects and 1911 grip safeties.

Regardless of "your impression" it is a fact the the Victories did have a (failure prone because they got dirty and quit working) hammer block, and after the Navy "drop" incident, it was changed to the current version. That's pretty easy to research, if you choose to learn about this.

 

[PERAZZI]

1911 grip safety on your useless list?? I thought this was JB's only safety requirement, the sear blocking slide safety was a useless gov't requirement.

 

[tomcatt51]

The grip safety was added to meet Army bid/trials specs back in 1907(?). It wasn't part of the original design.

 

[David LaPell]

I also wonder why you would need a Dremel on any part of the inside of a Smith revolver. The most aggressive piece of hardware I use which is following Jerry Miculek's trigger jobs is an India stone and I have done quite a few action jobs with no problem. I think your issue might be the hammer block but from what I know is that the sideplate won't go on if the hammer block is out of position unless you pound it in place. You might have to back off your strain screw a bit. I know on some of my guns I replace the strain screw with a shorter screw altogether because I had some of the binding issues. Back your strain screw off and you might get it to work. I know I have had to replace most of my Strain screws with set screws of the proper diameter but much shorter when I put in a different spring.

 

[Pig Hunter]

I had a 19-3 with a similar problem. The hammer block was interfiering with th rebound slide as it was not properly fitted.try assembling without the hammer block,and lighter spring and see what happens. If allworks well fit the block and go shooting.

 

[hotrod150]

I've had some trouble with the trigger not wanting to return when I tried to drop in a hammer or trigger from another gun. Most recently, I dropped the bobbed hammer from my model 60 into a newly acquired model 60-- it seemed to cycle fine but when I put on the sideplate the trigger would hang up on the return stroke. I even tried switching the hammer & trigger from gun to gun as a set-- no good. With the hammerblock out, the trigger returned just fine. I'm an OK parts changer but no gunsmith, so i finally gave up and put the hammers back into the guns that S&W intended them to be in and called it good. (pissed me off though)