Questions on getting a S&W Model 52 working properly

First topic message reminder :

One of my friends from my shooting club had a Model 52 that most of the time refused to fire.  The primers looked like they were hit fine by the firing pin, but the rounds didn't get off.  After sending it to S&W twice, and getting advice from everyone at the club, he found the fastest way to resolve this - he bought another M-52 that works perfectly with any ammo he feeds it.

I asked him if he was going to sell the old gun, but he didn't want to sell it to someone who would be as frustrated as he was.  I told him I'd like to buy it, if for no other reason than to have a gun to learn how to work on, as I hate the idea of doing anything to my own M-52.  We agreed on a price, and I took it home.  I spent much of the rest of the day cleaning and examining it.  It looked like it was packed with old oil/grease, the recoil spring was backwards, and the barrel had lead in it which eventually came off with Hoppe's.  

If I can't get it to fire reliably, I'll come back here and ask for advice.  For now, I have a question about the slide.  Comparing this gun with my own, there are three holes on the top of the slide on this gun, that don't exist on mine.  Would anyone here recognize if they might be for a rail, and if so, who might sell the rail?  I will measure the hole spacing. (I sort of gave up on steel sights because of my eyes, but who knows, maybe they will work better now than years ago, since I had the cataracts repaired.)

Also, are there any books that were written on how to work on the Model 52?  I have books on 1911's, and revolvers, but this gun is very unique.  I certainly don't want to do something wrong unintentionally, that I could have avoided.

Take out the filler screws and look at how far the holes go down

Good ideas there, Could have a burr inside the firing pin channel due to the former slide mount. Hard to diagnose things from afar.

Brownells, Numrichs, Ebay all have exploded diagrams of this pistol. There is not too much in the ignition components that is scary. Punch the pin out of the mainspring housing after the slide removal and drop all the the stuff out, wash everything down with Naptha and reassemble. Take pictures along the way if you have too.
My bet is the back end is full of goo and dust bunnies.

How to replace the mainspring:

From Donk52, on S&W Forum...  Safety removal - the plunger and spring is in a different location on the 52, it's on the other side, but the procedure is the same"

The 52 is pretty much a modified 39 smith...on the safety he was luckly the little detent and spring didn't take a trip across the room BTDT.. covered with a plastic bag is a good feature when taking it apart

Dr.Don wrote:I vote for making sure the firing pin and its channel are not all gooped up.  I would for sure check this before replacing the mainspring.  Swapping the uppers will tell you whether the mainspring is usable.

I'm 99% sure we found the problem.  If you look at the first photo at the beginning of this thread, you see three screws filling in holes that were made for mounting a sight.  

I wondered why the firing pin felt like it was moving through gravel as I pushed it in and out.  I figured the chamber was full of dirt, but when I went to clean it, there was no dirt to speak of.  One of the fellows in the S&W forum suggested that the holes for the sight might have a burr on the bottom.  Worse than that, at least one screw was screwed in so far, that it was binding the firing in spring. The "gravel" I felt was each coil on the spring hitting that screw.

No wonder the tech people at S&W couldn't fix it - all of the S&W parts were fine.

I'm happy it seems to be fixed, and thanks mostly to Don in the S&W forum, I now feel comfortable disassembling the gun far more than I would have dared to on my own.


Moral of this story - before blaming the gun manufacturer and their parts, check out any aftermarket stuff that was done to, or added to, the gun.    Sheesh.....

Jglenn21 and Bruce Martindale had it nailed for you on this forum. Can't be giving that other forum any credit.

If I understood what they meant, this would have been solved long ago - I wasn't smart enough to realize what they were referring to.  In retrospect, it's obvious.

It was the screw, not a burr, as once I backed out the screw a few turns, I could no longer feel any obstruction when I pushed a small tool into the channel - the obstruction was gone - but yeah, there still could have been a burr in addition to the screw.  

My fault - and these guys were smarter than the technicians at S&W who twice tried to fix it, and couldn't.  

If I was smarter, I'd have put two clues together.  Pushing the firing pin in an out felt like "pushing a rod through gravel" (my words), and then not finding any debris in the chamber.


I never, at any time in the past, really even thought about how the firing pin and spring worked.  No experience at this.  Most of the reason for buying this gun was to learn how to work on an M-52, and I learned more in the past two weeks than in the previous 75 years.  'Jglenn21 and Bruce "nailed it", but I didn't know enough to understand what they meant, and the implications.  Of course, now, in hindsight, it all makes sense.  So this gun has been "broken" for about 30 years!!!!

LenV wrote:.....You have two identical pistols. One works and one doesn't. You can narrow down the culprit in very easy steps. Step 1. Swap....    parts.

I asked Don, who assembled the Model 52 guns at S&W about this.  He said something about parts being assembled when the guns were "white".  I'm not sure what he meant, but he advised me not to swap the slides.  Each slide is matched to the frame.  The concept sounds fine.  I will ask him what he meant by "white".

jglenn21 wrote:Take out the filler screws and look at how far the holes go down

Thanks - you have the right answer.  The holes go all the way through, but in my case, at least the rear screw went all the way through, and then some.  I could see it looking into the back of the firing pin chamber.  

They were not Locktited in place.  Anyone who might have checked if they were tight, could have turned them down too far.  

It took me several minutes to appreciate that the holes were literally going into the firing pin chamber.  
Had you told me about all this two weeks ago, I'd have said, "I guess so, but why is that a problem?"  

Maybe I've progressed a bit further in the School of Gunsmithing, but I'm not yet even at the 6th grade level.....

Firing pin spring uses up much of the energy from the pin being hit by the hammer, and by the time all the coils go by the obstruction one by one, most of the energy us used up, leaving very little to hit the primer with.  More things I've just learned.   Thank You again!

This is actually not an unusual problem.  Rail get mounted and uses the correct length screw to have proper thread engagement.  Rail gets dismounted and owner assumes they can use the same screws to fill the holes - wrong.

I just discovered a similar one.   I purchased Marvel Unit 1 with optical rail installed.  The screws were tight, but as I cleaned everything, I noticed the rail itself was not tight.   It turns out the screws are the correct length for the Iron Sight rib which is thicker.   The screws are too long for the optics rail and bottom out in their holes. I'll cut new screws over the weekend so I can mount either rib with full thread engagement.

Actually, the screws I took out were set screws, with a flat blade gap on top.  Now I need to find some regular screws, very short, to replace them, or re-use them after locktiting them in place.  I'm pretty sure the guys I got the gun from removed the optical sight, and just found some small set screws to plug the holes, which means there probably isn't any "burr" as the first owner shot it with the optics for a long time before putting the gun away in his safe.

mikemyers wrote:

He said something about parts being assembled when the guns were "white".  I'm not sure what he meant ...

Most likely "before they went into the bluing tank". I'd be more curious about what he means by assembled in that case. The trigger parts, barrel etc. would not be blued. Maybe he's referring to the process of selecting and fitting the slide, frame and other parts.

That rings a bell, the blueing.  I will find out.

There are three pages of discussion, starting here:
http://smith-wessonforum.com/smith-wesson-semi-auto-pistols/585908-s-w-model-52-2-failure-fire-quite-often.html

Assuming you don't want to go through all that, I'll ask Don tonight.

From Don:

"The frame and slide are mated and sent off to finishing.  
The "small parts" are fit to each individual gun.  
Things like extractors, springs, and plungers and various pins are pretty much generic to the 52.  
The parts that are unique to each gun are, barrel/bushing, sear, hammer, drawbar, slide stop and many others.  
There's a sort of finesse to the assembly of parts to achieve the desired function of the gun."

mikemyers wrote:From Don:

"The frame and slide are mated and sent off to finishing.  

Yep, there you go. I definitely agree to keep the frame and slide together on such a gun, even when testing.

I spoke too soon.  
Went to the range this morning, and the gun behaved same as before.

My UPS package from Brownell's arrived with the new mainspring.

Old spring is 2” long, .27” diameter, .05” wire, and 22 coils (20 active coils).
New spring is 2” long, .27” diameter, .05” wire, and 18 coils (16 active coils).

The new spring is would in the opposite direction from the old spring.

I had a lot of trouble re-assembling the backstrap.  I had to use the trick of clamping the spring to the backstrap with a tie-strip, then get it in place, then cut the tie-strap.

If you guys know and understand coil springs, you'll know what reducing the number of coils does.  
I will test again tomorrow.

If that doesn't fix it pull your firing pin and check it and the pin..also the channel for burrs. I'd also leave the rail screws out to insure they aren't draging while.you test

They're possibly 'filler screws', made for plugging unused holes.

Brownells has these with a small flange at the head end, so they bottom out when installed and stay tight.

Didn't fix it.  First five rounds were perfect, then it started failing to fire.  Mysteriously, some of those rounds didn't have any dent in the primer, nothing!  The person before me, and I, thought the primer pin chamber was clean.  I guess I do that again.  I just got my new firing pin spring today, but that's not likely to be the problem.  The firing pin itself could have an issue - ordered a replacement today.  The fellow who worked on it before me had to file something on the 'safety'.  I think getting a new one is reasonable.

Maybe I just push it off to the side for a while, and think about it some more.  If all else fails, I can send it to Dave Salyer.

Are you sure the safety lever isn't slipping down some and blocking the hammer from hitting the firing pin?
You do know you can dry fire the 52 with a round in the chamber as long as the safety is on.  Not a safe practice but can be done.  Sounds like the safety might be the problem and blocking the firing pin,  getting hit light or not at all.

Virgil

I don't know what to check, and I'm not "sure" of anything.  I ordered a replacement firing pin and safety.  Will swap those when the parts arrive.

The last person to work on the gun told me this afternoon that he had to file something on the safety.  I will try to figure out what he did, and where, and maybe your idea is right, that the problem is in the safety.  It "feels" it is where it belongs.

Yes, I knew I could fire at a live round with the safety on, but I don't do stuff like that.  

Any ideas on how to test the firing pin, using empty rounds with no primer?  Maybe put a piece of tape across the back?

Here is a thought.   Put dykem on the firing pin and spring, reassemble and live fire until it fails to ignite.  Then disassemble and see if the problem is coming from the spring and pin - for example, if the pin is hanging up in the breech, you would see a ring of bare metal on the tip of the pin.  At the least, that would let you rule out the pin and spring as being the source of the problem.  

In addition to the theory that the pin might be catching at the tip end, it also may catch on the hammer end and fail to protrude sufficiently.  Again, the end result of this test would let you rule out the pin/spring/frame interface.