Model 13-1 light primer strikes

[olympicmotors]

Help needed please , I inherited an early 70s 13-1 about 2 years ago. First new gun my dad ever purchased in early 70s. I know complete history of the revolver. Never any gunsmithing of any kind done to it.

Took it out first time in many years a few months ago and had numerous light primer strikes / failure to ignight. Removed grips and found strain screw had backed out a little. I tightened screw all the way, and took back to the range yesterday. It was better, but still had one light strike. Using winchester white box ammo. No problems with any of my other revolvers with tjis ammo.

Firing pin looks ok, what do all of you think? Time for new mainspring ?
Time for trip back to factory ?

Yes I have the factory wood grips also.

Any suggestions are appreciated. Thanks

 

[armorer951]

Personally, I wouldn't send it back to S&W for a number of reasons. Since the gun has not been used much or worked on during it's lifetime, I would guess that it needs a good, thorough cleaning and re-lubrication both inside and out. Be sure to check for debris or old lube under the extractor. (an old toothbrush works great for cleaning here)

Beyond that, the rear gauge or "headspace" may be out of spec. If you have some feeler gauges, the rear gauge (space) between the rear of the cylinder and the breechface should be between .010" and .014". (smaller is better, check after cleaning and wipe down) If it's too far out of spec, this could cause light strikes.

There are many other possibilities, (including interference between the rubber grip panels and the mainspring) but these are by far the most common, particularly for an older gun that has been in storage.

 

[olympicmotors]

Thanks , good advice. I actually did take the sideplate off and clean, and relube it. I will try to gauge the rear headspace and take a close look at the rubber grips also.

Much appreciated,

 

[Jason Demond]

Any time a S&W starts in with the light primer strikes, it's a good bet the strain screw has backed out.

There were a lot of little tricks back in the day to lighten the action on S&W revolvers. Shaving the sides of the mainspring was one, and shortening the strain screw was another.

At some point, S&W actually produced a shorter strain screw. It is not uncommon to find these installed on older used guns.

If you have the ability, you can stick a fired primer between the screw and the mainspring. It will stiffen the action some and give a little more tension on the main spring. More tension equals more power to the hammer. That would be the cheapest way to perhaps solve your problem.

If you replace the main spring, don't go with anything less than full power. I suspect with the strain screw tightened, and the gun still having the issues. You might have a shortened strain screw.

 

[olympicmotors]

Any time a S&W starts in with the light primer strikes, it's a good bet the strain screw has backed out.

There were a lot of little tricks back in the day to lighten the action on S&W revolvers. Shaving the sides of the mainspring was one, and shortening the strain screw was another.

At some point, S&W actually produced a shorter strain screw. It is not uncommon to find these installed on older used guns.

If you have the ability, you can stick a fired primer between the screw and the mainspring. It will stiffen the action some and give a little more tension on the main spring. More tension equals more power to the hammer. That would be the cheapest way to perhaps solve your problem.

If you replace the main spring, don't go with anything less than full power. I suspect with the strain screw tightened, and the gun still having the issues. You might have a shortened strain screw.

I appreciate the suggestion, but I intimately know the history of this revolver, and am fully certain it has never been worked on. My dad would not have ever taken the side plate, or even the grips off. I myself have been the one that shot it most over the years, and even then very sparingly. This gun has not seen 500 rounds through it its entire life.

I may try your trick of a fired primer under the screw. Thank you

 

[Steve912]

I may try your trick of a fired primer under the screw. Thank you

Get a pick or jeweler screwdriver, and pry the anvil out
of the cup. Will make it a lot easier to sit, on end of
strain screw.

Post a pic of the mainspring, with grips off, if ya got the
time.

 

[Protocall_Design]

Sometimes the factory firing pin is on the borderline of being too short. When that's the case, it take a heavier than normal hammer strike to reliably set off the primers.

IF that is the problem on this gun, (not saying it is) you can get extended firing pins from Welcome to Power Custom.

 

[bananaman]

My 10-5 , R.B. 2" that I won online was somewhat cosmetically challenged.
Everything felt great dry firing. At the range, had some light primer strikes. Indeed the strain screw had been shortened. SO, being a pack rat, I had held on to a shortened strain screw for a square butt. Put it in and Bingo, no failures again for over 3 years. Bob