I have a 625-4 that will only fire 100% of the time with Federal primers.That is frustrating because I am not always able to find Federal primers.
Any one here changed out their hammer nose to one that is longer?Are you able to use any primer with this fix? Do you get any primer puncturing ?
Where can I buy a longer hammer nose that works and is not too expensive?

I don't know of a longer hammer nose firing pin.

In the meanwhile, is your strain screw uncut and all the way in?
On a stock mainspring?
If so, put a primer cup under the strain screw to increase the load.
Are you using clips?

Do you have cylinder end shake?

Me? I use only Federal primers for double action revolvers because I have some with reduced mainsprings. I know they are hard to find now.

Stock mainspring and screw and no excessive endshake;still having problems.

Power Custom has new hammer noses that may be longer.

Alternatively, you can take off the one you have, grind back the face of the hammer .005 or .010, keeping the same angle. A belt or disc sander work well for this. Replace the hammer nose and it will go further in by the amount ground off the hammer.

Before using, you need to check that the hammer nose is not hitting the hammer nose bushing in the frame, or it will push the bushing proud of the recoil shield surface. If it's hitting, file relief on the hammer nose wherever it contacts. This will be on the top or bottom radius parts of the hammer nose.

__________________
protocalldesign.com

It’s not that easy I’m afraid. First off you need to weigh or measure your mainspring. You need between 38-42 oz of pull for that weight of hammer and your stainless spring. Fed primers are the standard softer easier ignited primers and CCI used to be the hardest but not sure anymore. If your spring set up is too light then that is your problem regardless of the screw.

Facing or removing hammer material will change the hammer seat relationship. It is usually easier to stone the hammer seat than removing material from the hammer face. Too much hammer nose or firing pin protrusion and you could have punctured primers if you shoot hot loads. Not good.

Rick

Let me also add hammer nose protrusion measurements
.055” optimal
.060” max

I'd try a primer cup or spent 22 case on the strain screw first. I think I'd get a replacement strain screw and mainspring second. These are easily replaceable parts that doesn't permanently alter the gun. Springs especially can loose strength over time

__________________
NRA LIFE
Reserve Officer 9yrs

Have you checked the rear gauge or "headspace"? Excessive rear gauge can contribute to reliability issues.

Is this a .45 acp that uses moon clips? if so, the moon clips can also create issues if they are damaged or out of spec.

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

I have not checked the rear gauge yet.I have just found out that the hammer is striking the frame too much at the bottom with off center clearance not allowing the nose to fully enter the recoil shield.
I have been firing the revolver with full moon clips and with Auto-Rim ammo with the same results.

Just to clarify have you checked spring weight and if so is it within spec and what is the protrusion measurement. If both of these measurements are okay and your problem remains even with auto rims then I suspect I don’t know without getting my hands on the gun. Are these primers igniting in your other guns and loads ?

BTW after a hit what do the primers look like ? Photos ?

You know this whole primer shortage thing kind of screws up custom comp revolvers and the way we used to set them up. Mainsprings were re-shaped and tuned and weight set for Fed or WW primers which had the softest cups but now all bets are off. Anyway I don’t think you should alter your gun so much that if Fed primers return you will be unhappy.

Thanks for the suggestions,I will when time is available check the mainspring.But,I think I just found the problem;the end gauge is 0.019-not good! I have some parts that I swapped out and fitting theme the end gauge is now 0.004-a little tight but I will see how that does at the range.

I guess I should have asked or you should have told us the gun is undergoing ongoing modifications and part swaps.

Rick

What is end gauge. Do you mean cylinder gap?

What parts? Need to check headspace. If using same cylinder and barrel. Headspace more than likely increased making thing worse.

Well to tell you the truth it was not undergoing modifications but when Armorer951 asked what he did he shook out some cobwebs from the old mind and I remembered I had not checked the headspace.When I did check it I found it to be excessive and having a few parts I began to see if I could get the revolver to spec.I tend to check a lot of things and then forget to check some crucial specification.Getting old is not fun!!!!!

Bruce,end gauge is headspace measured from the recoil shield to the loaded cartridge under the hammer nose.I replaced the extractor star and for once the headspace was what I noted.

The old trick of installing an empty primer cap onto the strain screw really can work. It may sound like a wives tale but it has "fixed" two of my revolvers over the years. If you have a primer available try it.

Thank you ! If this headspace change doesn't do the job I will try that.

I’ve built a number of the early issue 625’s years ago and headspace was always a moving target with early moon clips. Anyway I have two right now that perform well with loaded chambers measured headspace at .008”. I know Ronnie Power likes to see .006” but I am good with a bit more. If you elect to gauge with empty cylinder then measurements should run .093 to .096 but again mine shoot reliably with .098” .

With plenty of spring weight and all the parts including nose protrusion correct you should have reliable ignition. Don’t think you can tweak an N frame DA to 6 lbs or less and have a reliable double action revolver. It’s a lot more than springs and aftermarket gizmos. If you have a 8 lb pull your doing good and it should shoot well if you do your part. Don’t believe these guys claiming 4-5 lbs pulls cause it’s either BS or they don’t know how to set up and weigh.

Good luck
Rick

Milton you don’t need to play that game if your spring weight is correct. You need to measure your DA pull to know what your spring is set at. Unless you know your spring weight and how hard the hammer hits you’re just chasing you tail. Of course you if don’t care about DA trigger pull so much then go ahead. Do you have a gauge to measure with ?

The factory spec for the rear gauge (headspace) on the 45acp is .090" - .094".

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

That’s funny all my old gunsmith class notes and later records from Ron Power say .093-.096” max. Actually I don’t think I ever had a 625 that would gauge as tight as .090” or even .091”. I can’t imagine most 625’s with moon clips even turning with a gap that close. Maybe auto rim ? But I’m sure your right it’s just not something I’ve ever run into. Maybe the 25’s were set up a bit different.


Rick

The factory even gave the recommended measurements to us in metric......

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

Yes ,set with a 45 Auto Rim.

Just checked the headspace again without a round in the chamber and got a reading of 0.092.Sorry my feeler gauge does not read in metric measure!!!

Since there are two ends, headspace and cylinder gap are defining terms.
a measurement of .004" is indicative of cylinder gap. As noted headspace is measured from cylinder to recoil shield. Sorry for questioning the numbers.