I recently acquired a 4006 in absolutely immaculate condition. After getting it sighted in, I can say that it shoots fantastic. However on the two occasions I have taken it to the range I have experienced failures to feed. Today I noted carefully when this was occurring. Every time it happens it is on the last round of the magazine. I have two factory mags that appear to be practically new and it happens on both with the same degree of regularity, which is about one out of three mag loads. I was only filling the mags with five rounds. Today I shot 100 rounds of new factory ammo. 50 were brass cased and 50 were aluminum. The feed issue occurred at about the same rate on either brass or aluminum.

The gun is twenty years old but looks brand new. What do you think is going on? Could it be this gun was "used" as a house defense gun with loaded mags that just sat in a drawer for many years and now the mag springs are too week to feed the last round? I'm sure I don't know, but that's the only thing that I can think of. What are your thoughts? Any thoughts or suggestions will be greatly appreciated. Thank you.

It's possible the mag springs are getting weak. I replaced all mine for my 21 year old 1006, even though I never shot it much or kept the mags loaded. I'm thinking it's either the mag springs or the ammo. Since you have ruled out ammo, that leaves the springs, especially since you said it happens only on the last round. Also, be sure your thumb isn't riding the slide, even just a touch.

Mag springs are not very expensive if you can find them. Check with www.gunsprings.com or MidwayUSA. I think I found mine at Gunsprings. You can get a 3 pack for $17.29 or $7.49 individually. They have the 5% or 10% extra power. Either one would work fine.

I'd change the mag springs for starters.

Well, considering that S&W recommends to its trained LE armorers to replace mag & recoil springs in 3rd gen's either every 5 years (duty guns left loaded all the time) or every 5,000 rounds fired, I'd start by replacing the recoil and magazine springs.

Are the followers yellow or blue? If yellow, (older follower revision), then the mag springs are really old. (S&W might send you the current blue followers at no charge if you call and ask.)

FWIW, I had a friend at another agency (their head armorer) who couldn't get the money allocated to replace the recoil & mag springs in their 4006's at the recommended 5 year interval. He said he was told that since the guns were all running fine, there was no reason to spend the money.

He had to wait until it reached the point where many of the issued guns suddenly started exhibiting numerous feeding stoppages during periodic training/quals before he was able to get the money to re-spring the guns. FWIW, that happened when the guns had reached the point of having been in-service for 7 years.

BTW, it's not uncommon for aging & weakening mag springs to start causing either failures of the slide to lock back on an empty magazine, or failures-to-feed during the last 1-2 rounds in the magazine load. Ignore those signs, and the failures-to-feed usually start happening earlier in the mag loads.

Also, a weakened recoil spring can start to cause feeding stoppages, failures-to-extract and failures-to-close-into-battery.

Now, mix weakening recoil AND mag springs, and you can really start to get some interesting head-scratcher stoppages & malfunctions.

Congrats on the new 4006.

Replace the mag & recoil springs, clean and lubricate it properly (neither under nor over-lubed, and not where it ought not to be lubed), use good quality factory ammo made by one or another of the major American ammo makers, and enjoy.

Just my thoughts.

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Ret LE Firearms inst & armorer

Thanks guys for the confirmation regarding the possibility of my problem being mag springs. I've got new ones ordered. I sure hope this will resolve the problem as it is a quick, easy and cheap fix.

Like Bozz10mm did for his 1006, I'm going to order new mag springs for my 4516 and 4506 even though they have given me no grief.

I didn't see your edit Bozz10mm soon enough to order from Wolff. I found them at Numrich. And as a head's up to others, they are more expensive at Numrich and I didn't see that they offer the 5-10% more power option. I really appreciate the help.

Since I only use 2 mags at a time with my 4006 I have several others that have never been used. Are you saying that these mag springs need to be replaced every 5 years as well?
Incidentially noting the description of the 4006 that started this thread I wonder if it's ever been fired much up til now?

If it hasn't it could very well still require breakin.
Jim

Fastbolt,
Thanks for the great reply and your experiences and knowledge about not changing the springs. Regarding the followers, I have one of each (yellow and blue). The blue one is marked AccuGuide.

I'll also be ordering mag springs and recoil springs for all my 3rd gens. Better to be proactive on this issue than reactive. Thanks.

Jim,
I thought the same thing. This gun does not look like it has been fired at all. The only evidence I could see was a tiny bit of discoloration on the mag followers where the brass drags on the plastic as it feeds. I've got about 200 rounds through it and there seems to be no easing of the problem. Here's a couple of pics of the gun. The shiny area on top of the hammer is from the photo lights. It isn't wear.

The recommendation has always been said in connection with mags that are being carried/used everyday (in other words, left loaded on gun belts, or in lockers between shifts, all the time).

Never heard anyone suggest we needed to re-spring any of the new/unissued mags we may have sitting in parts inventory.

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Ret LE Firearms inst & armorer

Nice looking 4006. Looks like one of the blue carbon steel hammers and a machined carbon steel, flash-chromed trigger.

Don't fiddle with disassembling the adjustable sights. Getting parts for those older sights, unique to the S&W guns, can be difficult.

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Ret LE Firearms inst & armorer

Not knowing your experience with the 3rd gen .40's, make sure the follower & mag spring orientation is proper when reassembling the mags. I've seen a couple instances where someone put the spring or the follower in backwards.

The higher top/front of the mag spring rests in the area behind the front "legs" of the follower.




Make sure the front lip of the metal butt plate catch is inside the mag body, and doesn't slip out in front (between the bottom of the mag body and the top of the butt plate). (No pic of that problem.)

Don't be stingy on recoil or mag springs. I like how an armorer instructor for another gun company said it during an armorer recert I attended earlier this year.

He said, "Fresh springs keep guns alive."

The .40 is a hard caliber on guns. The recoil forces and slide velocities are harder in the .40 than on the 9/.45 guns.

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Ret LE Firearms inst & armorer

If you can't easily get a new blue .40 follower, let me know.

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Ret LE Firearms inst & armorer

Besides the obvious (color), is there a difference between the yellow and blue followers? Spring length or force rating, are two possibilities that come to mind. Also, was there a specific reason for the change?

I recently purchased a very early S&W 4006 (SN: TFH0666) produced in August 1990. As this weapon was originally purchased by a collector (accumulator) in North Carolina, it is in 'NIB' condition and came with two 11 round magazines of the yellow follower variety. During my search for additional 4006 magazines, all I could find were ones with blue followers. As they're still "in the mail," can I expect any change in performance from one to the other?

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I've gotten some variable and even ambiguous answers to that question over the years. At least a couple guys basically shrugged and said they didn't know why the difference of color occurred.

I've not noticed any obvious difference when eye-balling them, myself. Doesn't mean my eyes are precise enough to catch anything subtle, though.

I've been told that it might've been a subtle change requested by the engineers, or it might've been something as simple as a change of vendors and/or some spec of the plastic material being used. Dunno.

I've been told of some agencies who changed out their existing yellow followers for the new blues ones, if only to have the latest revision.

Nothing in the way of a "recall", or told to "stop using them", that I've heard.

If you call and order replacement 3rd gen .40 followers, you get blue ones.

I've seen my fair share of yellow .40 followers still being used in older 4006's. None of the owners had any particular complaints to report. I've replaced them for the owners whenever I've had extra new blue ones on hand. (They feel better about it, if nothing else. )

If it were me, I'd replace the original recoil & mag spring, if only because it's an easy step to take to help prevent unnecessary battering. (I've seen some folks store pistols with the slides locked back.)

Mag & recoil springs get their own fair share of occasional revisions, too, so why not switch out any old/original springs for the current ones?

Congrats, BTW.

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Ret LE Firearms inst & armorer

Thank you for the feedback. Based on what I've read here, I was planning on doing the spring upgrades after the blue follower magazines arrive. However, as this piece appears to have not been fired much, if at all, I'm going to sight it in and run a box or two through it to see how it handles (feeds and ejects) various types of ammo using both the original and newer magazines.

Thanks again!

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I thought the blue followers were originally in the serial numbered LE mags and the yellows were regular, then they went to blue for no particular reason.

You should have at least 10 magazines, Set your reminder to rotate monthly the 4 or 5 you actually keep loaded, you should never have a problem.

REALITY...Unless you want to become a Denton James Ward,(Killed by a Black mob), I suggest you boys start making sure you are the LAST MAN STANDING!

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Spring is where I'd start. Buy some mags fellas!

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John 5:24