Hello,i need your help for the following problem. I try to sumarize:
Last september i buy a S&W 28 Highway patrolman 6" in mint conditions. I shoot with it almost every cartridge available, also reloaded without any sort of issue. The only problem for me was the heavy single action trigger pull. So i decide to install a Wilson combat pack, i install the 13 lb. Reduced Power Rebound Trigger Spring and the Reduced Power Hammer Spring (also if for my N frame it seems too short). I adjust the strainscrew and i shoot almost every ammo available (commercial or reloaded) without any sort of problem and the trigger pull weight is improved, i was satisfied.
In March, Corona virus lockdown until end of May, revolver in the safe. About one month ago i begin again to shoot and here begin the problems. Same reloaded ammo, same primers, same priming tool, same powder, same cases and so on. The situation degenerates in 100 rounds. In the beginning a misfire every 5 shot until 4 misfire every 5 shot. I try another primer brand, same result. Panic.
I screw the strainscrew and the situation improves but still today 2-3 misfires every 50 rounds, and the trigger pull is now heavier then before. I take down the side plate and the first thing i see is an anomalous, very light, sign on the right side of the hammer. So i see that between the frame and the hammer in the top part of the hammer the space is not simmetric. At left a paper piece can enter, on the right the paper piece in one point can't pass. My doubt now is that something happens and the hammer is no more simmetric in his position. So the friction between the hammer and the frame on the right makes the rotation slower and gives misfires. Anyway i try to follow the hammer during his rotation with my thumb and i feel a very light variable friction. Did i make a mistake during the reassembly of the trigger-hammer when i install the wilson springs? I'm almost desperate. Thanks a lot in advance for your help.I wish you the best for your health.
Ciao.
Simone

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Simone,

First, I don't think the position of the hammer in the frame is the problem. If the hammer were hitting the frame, or rubbing the frame to the degree that it affected reliability, there would be some sort of major rub mark or contact site on the frame. Remove the mainspring and re-install the sideplate.......if the hammer moves freely under the sideplate without tension from the mainspring then this is not the issue.

Also, the mainspring strain screw is not meant to be "adjustable". It should be screwed in all the way, all the time. (tight) You don't mention if these misfires are happening in both single action and double action??

If you have ruled out things like shooting debris (dirt) under the extractor or in the cylinder assembly, and excessive endshake to the point where the rear gauge or "headspace" is out of specification, then the likely source of the problem is your substitution of the Wilson aftermarket parts, and the attempt at "adjusting" the mainspring screw. After a good cleaning, go back to the factory installed parts (mainspring and rebound spring) and see if the problem goes away. These and many other aftermarket parts are not always "drop in" reliable.

Carter

__________________
Ret. LE, FA Instr, S&W Armorer

Springs that have been used, tend to "let down" or have a reduction in strength. How much it lets down, pretty much depends upon the quality of the spring. This is normal.

Now several other things may have happened here. First, the reduced power hammer spring is meant to be used with the strain screw tightened all the way in. Second, the strain screw has to be original, unaltered length.

Second: if the strain screw isn't all the way in, it can work loose. This will reduce tension and cause misfires.

If the hammer rubbing on the frame really bothers you, Power Custom/Grand Masters LLC sells hammer shims (available from Brownells if shipping out of the country is permitted) to center the hammer better in the frame. However, as said above, this probably isn't your issue.

Simone,

You mentioned in the beginning that the replacement hammer spring was short. The first thing I would do is replace it with another brand spring like Wolff, etc. Whatever you can get in Italy.

Also verify that the hammer stud the hammer pivots on is not broken.

Giorno di padri felice!

__________________
Jim
S&WCA #819

trigger shims are your friend.

Dear All, thank a lot for all your contributions.Today i replace the Wilson hammer spring with the original smith & wesson spring of the revolver, and i tighten the strainscrew. Now percussion appears more strong and also the lateral friction of the hammer appears to be reduced. Tomorrow i will test it to the range and we see if the issue is solved.
I discover also that this site: S&W K L N Shim Kit
ships the shirms kit internationally. Usally for me is impossible to find a dealer shipping parts outside of USA. I was asking also if screws (strain screw and side plate screws) which are simple parts can be shipped outside of USA.
Anyway, considering my passion i have to plan a travel in USA, in this occasion i will buy all the little parts which are impossible to buy for corrispondence.
Best regards and stay healthy.
Simone

It’s more than likely the reduced power hammer spring. Especially in double action.You can turn the strain screw all the way in, and that may help, but if the problem continues replace the spring.

The strain screw was never designed as an adjustment... it is made to be kept tight.

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S&W factory revolver armorer

Until you get a replacement spring and to improve the trigger pull of the original spring, you can use the weak spring with a shim under the strain screw.

__________________
Jim
S&WCA #819