625 misfires/45 auto rim

[KAYDADOG]

DocSavage, I had a similar problem with a new S&W 929 9/mm pistol using moon clips and CCI primers.
Talked to S&W and they stated to use factory ammunition which is never going to happen to a reloader.
Any reloaded ammunition should perform very close to factory rounds.

Changed to a longer firing pin, no change.

Long story short talked to someone at my firing range. He suggested to try Federal primers which may use a softer material.
Bought 100 to try and loaded them to the same parameters of the ones used with CCI primers.
Went to the range and guess what had zero misfires.
Luckily I bought 10/K Federal small pistol primers when they were still $150 per/1000 not like $600 now.

Only experienced misfires in this particular gun. Sometimes the solution can be a component used.
The 9/mm rounds with CCI primers work fine in any of my semi-auto guns.

Hope this helps. Just something to look at.

[tejano]

My 929 is also a federal primers revolver. I seat them down hard using a Lee Turret Press. Also, I have had my best luck with Lapua, Winchester, and Federal cases. My 625 has been federal primers only ever since the mods at SDM Fabricating were done years ago.

[DocSavage]

I have CCI and Remington primers on hand may try the R-P primers next. Will have to wait for primer prices to go down when that will happen Is anybody guess. I'm happy to have figured out the problem short of sending back to S&W or having a local smith work on it. I've got loads of 45 auto ammo and moon clips the auto tim brass makes life a bit easier to shoot

[slughammer]

..... These were R-P cases will try the rounds loaded in Starline brass later this week. Will update afterwards.

Can you measure the rim thickness of the RP and Starline brass?

Sent from my SM-G781U using Tapatalk

[Outpost75]

IIRC the 625 revolvers have a frame-mounted firing pin, rather than one pivoted on the hammer nose, as on older models. You need to measure the driven protrusion of the striker point with hammer down and trigger held back, which is easily done with the cylinder and yoke assembly removed. On a .38 or .357 driven protrusion should be 0.028-0.032". Not sure of current spec for a gun using large primers, but my M1917 S&W and Colt New Service with hammer-mounted firing pins are 0.040" and will set off rifle primers if primer pockets are cut deeper for them. They produce 0.018" copper indent, using the government gage. About the same as a .44-40 Winchester 73 or 92!

Head clearance and cylinder end shake are also factors as both reduce striker indent. WW2 spec for M1917 revolvers being rebuilt for reissue was 0.012" minimum on annealed copper cylinder held in the government gage holder. This is the same as CPB spec on .357 revolvers and for M9 pistol.

With frame-mounted firing pins you can have the issue of primer cup material flowing into the firing pin bushing when there is excessive radial clearance of the bushing hole around the diameter of the striker point. Most common in .357s. If thin cup primers used in +P+ or magnum loads produce punctures at the striker indent fouling and debris entering the firing pin bushing can bind the sliding fit of firing pin and reduce striker energy through frictional losses and cushioning effects. IMHO this was a poor design for police service!

When I was at Ruger in 1980s we went all around the mulberry bush to mitigate primer flow into the bushing and to insure adequate copper indent on contract guns. On CPB contract production they wanted 0.030" min driven protrusion with 0.012 min indent on copper. Normal commercial product was normally l held to 0.028 driven protrusion with 0.010 copper indent. good spec for .38 and .357 whichncurrent S&W often fail to meet.

[M-Tecs]

The early 625's had the hammer nose firing pin. It appears -4 was when the switch was made since the 625-4 can be found with either hammer style. The Smith & Wesson S&W Model 625-4 still has the pin in the hammer.

Pics here https://lsbauctions.com/5221/smith-w...case-mfd-1995/

[DocSavage]

Both revolvers are 625-8.

[376Steyr]

Both revolvers are 625-8.

Perhaps the Internal Lock System (AKA the Hillary Hole) has somehow gotten gummed up and is slowing the hammer fall?

[M-Tecs]

You can purchase a longer firing pin here.

https://tkcustom.com/products/s-w-co...ded-firing-pin

https://www.brownells.com/handgun-pa...prod60302.aspx

https://www.brownells.com/handgun-pa...-prod5483.aspx

https://www.apextactical.com/apex-re...firing-pin-kit

http://www.powercustom.com/store/ind...roducts_id=303

https://www.wingtactical.com/firearm...ame-revolvers/

Some good discussion here

https://forums.brianenos.com/topic/2...ed-firing-pin/

https://www.1911forum.com/threads/s-...roblem.402246/

[DocSavage]

Perhaps the Internal Lock System (AKA the Hillary Hole) has somehow gotten gummed up and is slowing the hammer fall?

Don't have a key for the lock but was thinking of giving the internals a spray of carb cleaner. The problem is with 2 different 625s one much worse than the other. I have vernier and will measure rim thickness and compare with drawings in Lyman manual and compare to Starline brass.

[DocSavage]

Just measured rims R-P .083 Starline .085 wiki say rim thickness .0827

[megasupermagnum]

Don't have a key for the lock but was thinking of giving the internals a spray of carb cleaner. The problem is with 2 different 625s one much worse than the other. I have vernier and will measure rim thickness and compare with drawings in Lyman manual and compare to Starline brass.

If you've never had the side plate off the thing, that is definitely the #1 thing to start with. Carb spray isn't what I would try, but maybe. I don't think you could do very good spraying it down by the hammer. You definitely want the side plate off, and give it a proper cleaning. Clean your firing pin while you are there.

[DocSavage]

Not going to remove side plate on my own too much of a chance of part s launching themselves into orbit or that black hole where all small parts seem to end up. Will look at IL with a jeweler's loop as it might be an allen screw or torx.
Worse comes to worse I'll contact S&W for a key.

[slughammer]

Just measured rims R-P .083 Starline .085 wiki say rim thickness .0827

OK, so the brass is in spec.

Do you have a set of feeler gages? A few of us could check our headspace and we could compare measurements.

My 625 Model of 1989 with the hammer mounted firing pin measures right about .102 - .103 for headspace.

Firing pin protrusion is not as easy to measure, but you can visually look at it by opening the cylinder, then pull the thumb latch to the rear and hold it there, you can now pull the trigger double action and see the firing pin protruding from the frame. After that you can tie the trigger back and examine it further. (3 hands may be necessary.

https://i.imgur.com/Pw5SW5K.jpeg

https://i.imgur.com/Q5O1Wxk.jpeg

[DocSavage]

Going out Saturdsy with a batch of 45 acp in moon clips to see if I get the same results as the auto rim brass. Might just get a longer firing pin and have my local gunsmith install it. %20 for the pin and $45 for labor,cuts down pn the aggrevation dept.

[Geezer in NH]

Trigger job done on it check the strain screw some smiths take a little of the tip of the screw so even tightened down it does not hit the mainspring enough. I would try a new factory screw.

[DocSavage]

Bought the 625 used but it's been reliable up until recently. Have checked the strain screw first thing though I was thinking of putting a small piece of lead shot under the strain screw.

[rintinglen]

Back in the day when revolvers ruled the earth, at least the holsters of law enforcement portion thereof, there were a fair few fellows who would grind the tip of their main spring strain screws to lighten the trigger pull. Sometimes to the point of causing light hammer strikes. A quick and dirty fix for this was to take a spent primer and pop out the anvil. Back off the strain screw until you can just slip the primer over the shortened screw and then retighten. This usually fixed the problem.

Sometimes it took taking a small primer, popping out the anvil and inserting it inside a large pistol primer cap. I never knew this to fail.

In this case, I'd install a longer firing pin. Five to ten thousandths should do the trick.

[tejano]

Funny, I had completely forgotten about the spent primer trick even though I used it myself back in the 80’s. The odds are good that it will extend the life of a “relaxed” mainspring, especially with Federal primers. Mine is a 625-2 model of 1988 so the firing pin is on the hammer.

[DocSavage]

Pulled the grips off the 625 strain screw is intact,called Apex Tactical and ordered 2 new firing pins.
If I'm replacing one pin may as well replace the pins in both 625s.