Mk25 Navy hammer

[mi4]

Lately it happened a couple times that I pulled the trigger and hammer dropped but failed to stuck the firing pin. I can't find a pattern so far. What could it be? Thanks.

[Lonestargrizzly]

Hammer spring?
Have you cleaned it recently?
Maybe your firing pin is gunked up?

[dummykid]

did you oil your firing pin before? if so , it might be the build up dirt inside the firing pin chamber.

[Lonestargrizzly]

Is this during live fire or dry fire?
Cuz it may also be your ammo

[nikki#2]

Hammer spring?
Have you cleaned it recently?
Maybe your firing pin is gunked up?

Maybe it's corroded worse than mine?

[Lonestargrizzly]

Maybe it's corroded worse than mine?

Its possible. Im not too familiar with sig but on failure to fire I'd always go with the cheapest suggestion first and be suspect of the ammo.

[rideordie]

Not sure about the SIG but when my XD45 started doing that it was really dirty and the gunk build up was pretty bad. A disassembly and good cleaning fixed the problem.

[WaltKowalski]

Did you check the primer? Was it a light strike? (Slight dimple from the pin).

As others have said, could be crud buildup from excessive oil that could be inhibiting pin if that's the case. If there is no evidence of the light strike then there may be a problem with either the hammer spring or strut, or it could also be the firing safety pin lock or lever (see #28 in diagram below) for the pin preventing it from advancing.

[mi4]

Update: is this dirty?

[mi4]

checked main spring, nothing strange. Maybe E2 grip somehow interacted with mainspring?

[reagan8]

Update: is this dirty?

I've never removed my firing pin, so I don't know whether that's particularly dirty, but I think it really depends on how gummy that dirt in your picture is.

Does it wipe away easily with barely any pressure? If yes, probably a non-issue. If not, that's probably the cause; it definitely isn't helping.

Very interesting to see a newer 226. Mine's 20 years old and the safety lock / plunger is very different (rectangular not circular).

[mi4]

I've never removed my firing pin, so I don't know whether that's particularly dirty, but I think it really depends on how gummy that dirt in your picture is.

Does it wipe away easily with barely any pressure? If yes, probably a non-issue. If not, that's probably the cause; it definitely isn't helping.

Very interesting to see a newer 226. Mine's 20 years old and the safety lock / plunger is very different (rectangular not circular).

I wiped it away easily. Actually, it seems not the problem of firing pin ---- after I cleaned it, it happened again once (less than 100 rd fired since cleaning). So I removed E2 grip and inspected and reinstalled the mainspring yesterday. I will see if the problem is still there this weekend.

[CouchOperator]

Call Gray Guns. They should be able to give you advice

(541) 468-3840

[Monkeywrench]

You have a Gray Guns trigger? I had the same problem with mine. Back out the stop screw one quarter turn and you should be good.