6906 intermittent light primer strikes

[Aukula1062]

Had my daily carry 6906 out out to the range last week to do some shooting and ran into intermittent light peimer strikes were the cartridge failed to fire. I would fire 2 or 3 rounds with no problem then the pistol wouldn't fire. I extracted the round and saw a light primer strike, a very slight dimple. I set the round to the side racked and fired another round with no issues. I recovered the fired round and the primer strike
was centered and well struck by the pin. 2 more rounds and I experienced the same light primer strike. I stopped shooting the gun and took it home for a closer examination. The firing pin isn't hanging up on anything and moves freely in the channel when the firing pin safety is depressed.the decocking function workes, trigger seems fine and the gun cycles dummy rounds fine. Tommorow I'm going to disassemble the slide and see if there is anything that stands out as broken or not right. Any old 3rd gen guy out there that have seen this problem before? Any help would be appreciated. Thank you!

 

[JohnHL]

A common problem contributing to light strikes on the S&W metal frame, center fire, semi-auto pistols is a build up of "gunk" in the firing pin channel.

Pulling the manual safety body, releasing the firing pin and spring, and cleaning the channel typically restores the pistol to proper operation.

John

 

[JohnHL]

Did you try re-firing the light strike rounds?

Sometimes a primer will appear to have a light strike if it is not fully seated.

I'm still leaning toward gunk in the firing pin channel.

john

 

[LVSteve]

Factory ammo or reloads?

 

[stansdds]

As mentioned, hard primers (foreign made ammo) or primers not fully seated (reloads) can cause what will appear to be light strikes, especially if the main spring (hammer spring) is weak or was replaced with a lighter weight spring.

The other possibility is debris or gummy, dirty lubricant in the firing pin tunnel. The firing pin tunnel and firing pin really should not be oiled, but oil can get into the tunnel during cleaning and oiling of the exterior of the slide.

 

[kbm6893]

I’ve replaced the firing pin spring in all my used 3rd gen pistols and seen some nasty stuff in there.

 

[Aukula1062]

To answer the the ammo question, new manufacturer Geko 124 grn FMJ. I have had zero problems with that ammo in the past using it in the 6906, 915, 5906, 3953 and the 5946. Yes, I fired the 2 light primer struck rnds out of my 915 that range session. Of all my 3rd Gens, the 6906 is the only import. It showed a lot of carry wear but it doesnt appear shot out. Being honest here, i really dont remember how dirty it was since i cleaned it after i bought it. I'm not certain but I believe it to be an ex Israeli police pistol so I'm sure it has been used and abused. Hopefully it is just built up gack in the firing pin channel. Thank all of you for your help! I'll let everyone know what I find when I get it apart. I ordered a complete spring kit from Wolf plus a few more recoil springs as well.

 

[WR Moore]

Be very careful not to confuse the decocker/safety detent spring with the spring that holds the right side lever in place. They're very similar but different.....as you'll find out if you confuse them.

 

[Aukula1062]

Be very careful not to confuse the decocker/safety detent spring with the spring that holds the right side lever in place. They're very similar but different.....as you'll find out if you confuse them.

Roger that.

 

[BLUEDOT37]

I'm not certain but I believe it to be an ex Israeli police pistol so I'm sure it has been used and abused.
I ordered a complete spring kit from Wolf plus a few more recoil springs as well.

Good idea! I always change out all of the common use springs on my "new to me" purchases.

You never know how long its been since they were refreshed or if someone installed a reduced power spring(s).

Better to start with new springs & a good known.

.

 

[stansdds]

Wolff makes very good springs.

 

[Fastbolt]

Be very careful not to confuse the decocker/safety detent spring with the spring that holds the right side lever in place. They're very similar but different.....as you'll find out if you confuse them.

Abso-freaking-lutely.

Mixing up the ambi lever and body plunger can make for some hard, gritty and nasty decocking lever movement (and mar the inside surface over which the head of the plunger rides).

However, mixing up the ambi lever and body plunger springs can make for a nasty surprise when shooting ... as the ambi lever spring isn't strong enough to keep the manual safety assembly from rotating when the slide slams to the rear of its travel.

Well, trying to depress the body plunger spring under the ambi lever is ... hard.

However, the typical symptom of having switched the springs is that the gun will decock itself when fired, and the levers will remain in the On-Safe position. Often for each shot.

I knew another agency where a newly minted junior armorer made this mistake after inspecting duty weapons, and it wasn't discover until the next round of quals, where the guns used by the cops started decocking and remaining On-Safe when they were fired. They'd been carried in that condition for some months, so it was lucky they hadn't had any OIS incidents during that time.

Mixing up the springs is specifically discussed and warned about in the armorer manual, in both the manual text and the Trouble-shooting sections. For a reason.

FWIW, in the olderr 3rd gens the ambi lever plunger in the 9's/.40's had a semi-rounded head and shoulder, while the newer guns had a straight, wide headed plunger (first used in older .45's). It requires a lever with a wider notch for the wide head.

Manual safety 'body' plunger on left. The semi-rounded ambi lever plunger in the middle and the last revision of the ambi lever plunger on the right.



Older plunger and lever on right, newer on left.


FWIW, here is a 9/.40 ambi lever on the left, and a .45 ambi lever on the right.


The pin punch points to the extra 'tab' on the inside of the ambi lever, which helps prevent lateral movement. It was later determined that the .45 ambi lever needed to be used in the early 9/.40 slides when they were equipped with the optional spring-loaded, decock-only assembly.

It helps keep the assembly from shifting an potentially causing interference with the freedom of movement of the firing pin within the assembly. I learned about in one of the armorer update classes, and had to replace the older standard ambi lever with the .45 ambi lever. What was interesting was that when I called to order the lever, the parts guys hadn't yet been told about the need for it in decock-only guns.

Ambi lever spring (right) and body plunger spring (left). When new, the ambi lebver spring is painted light blue, and the body plunger is unpainted. The body plunger coils are thicker and it's virtually impossible to compress the spring between thumb and forefinger. The lighter tension ambi lever spring can be compressed between fingers. DON'T MIX THEM UP.


Just some thoughts.

 

[Fastbolt]

Oh yeah, we could always tell the guys & gals who drenched their weapons with solvents/CLP and oils ... because the excessive amounts would migrate into the firing pin channel and gunk up the firing pin spring (fill between the coils) and impeded the firing pin's movement. Light-strikes were the clue.

We recommended they didn't use excessive (slathered) liquids to the openings in the slide where they could easily run inside, but not easily run back out.

We recommended they point the slide down when scrubbing the breech face (let gravity help keep any liquids from running inside the firing pin hole; keep it away from the rear of the firing pin; keep it away from the nylon and steel plungers at the rear of the slide (bottom), since those opened into the firing pin channel; and the bottom of the manual safety assembly body (through which the firing pin moves).

FWIW, not introducing excessive liquids to the outside of the extractor, and the bottom of the extractor, is prudent. Notice the narrow slot on the bottom of the slide, to the right of the pickup rail? That opens into the extractor slot in the 9/.40 slides. Also, due to older machining methods in the early 3rd gen guns, sometimes a very thin bit of steel might break off at the rear of the narrow notch, and a 'crack' would form turning back toward the pick-up rail. Sometimes the small, thin bit would break off and fall away at the rear of the narrow cut. Cosmetic, we were told.