Need new magazine spring?

[DougE]

I was at the range yesterday and had the last cartridge jam twice in my 4043. The mag I was using is an 11 rnd mag and has a yellow follower. This particular magazine also fails to lock the slide back when empty every now and then. The spring feels fairly stiff when I press down on the follower but it'd be my first guess that the spring isn't stiff enough even so.

 

[DougE]

I was at the range yesterday and had the last cartridge jam twice in my 4043. The mag I was using is an 11 rnd mag and has a yellow follower. This particular magazine also fails to lock the slide back when empty every now and then. The spring feels fairly stiff when I press down on the follower but it'd be my first guess that the spring isn't stiff enough even so.

 

[Alk8944]

DougE,

Need more information, specifically are you shooting handloads, economy or first quality factory ammunition? What you describe is typical of under-recoil. The slide just isn't coming back far enough to reach the slide stop notch so the slide stop can engage properly or to dependably pick up the next cartridge.

If you are handloading then increase your charge weight by .2-.3 gr, even if you are at the book maximum. That should correct the under-recoil problem.

Another approach would be a lighter recoil spring from Wolff, probably 3# less than the factory standard if loading slightly above the manual makes you nervous.

 

[DougE]

Thanks for the reply. I was shooting 185 gr wwb.
The gun cycles fine until the last round which is why I was thinking maybe the mag spring is the culprit.

 

[Fastbolt]

The yellow followers were replaced by the current blue ones.

If your magazine is old enough to have a yellow follower it's probably old enough to be time for a new magazine spring.

Usually the early indications of a weakening magazine spring are failures of the slide to lock back on an empty magazine, followed by (or accompanied by) failures-to-feed involving the last round. Further weakening can often result in failures-to-feed earlier in the magazine load as the spring further weakens.

FWIW, S&W armorers are told to replace magazine springs in LE guns either every 5,000 rounds fired or else every 5 years (when magazines are left loaded). This is likely a conservative recommendation (better sooner than later when it comes to the reliable functioning of guns 'dedicated to defensive usage'). I've spoken to an armorer for an agency where their issued 4006's didn't start experiencing feeding issues related to weakened magazine springs until their folks had been carrying them fully loaded for 7 years. Better safe than sorry when it comes to something as easily replaced as a magazine spring, don't you think?

The newer 11-rd mag springs for the 4006/03 series have approx half of the spring painted light blue.

I've had a lot of our folks who carry 4006TSW's complain about how hard it is to load the 11th round into magazines, even after they've been carrying them for a year or so.

If you call S&W they might replace your older yellow follower(s) for free, and might even toss in some new mag springs (although mag & recoil springs are parts which are normally expected to wear and be replaced). Wouldn't hurt to ask. Probably wouldn't hurt to replace the old recoil spring while you're at it, either.

Considering the higher slide velocities often realized in the .40 S&W cartridge it's not exactly unexpected that weakening magazine springs might cause some functioning issues at some point.

Just my thoughts.

The yellow followers go back several years.

 

[DougE]

I'll go ahead and replace the spring and follower in that mag and see if it works properly after that. I'll also replace the spring in my other mag ( that one has a blue follower so it's newer than the other one ) and the recoil spring while I'm at it. I appreciate the advice.

 

[Fastbolt]

Let us know how it works after the spring changes.

It's just that replacing known older springs is one of the simpler and quicker steps to take when trying to diagnose something that seems to be spring-related.

Also, make sure you're using sufficient lubrication with the alloy frame. Lots of folks don't apply enough lubrication to prevent accelerated wear on the tops & sides of the frame rails.

Granted, I've seen as many functioning problems caused by over-lubrication, but those problems could be resolved by a thorough cleaning and proper lubrication. (It's surviving the malfunction, caused by excessive lubrication, long enough to get it corrected that's a bit tricky and uncertain.

)

Needlessly wearing away metal by not properly lubricating an alloy frame isn't as easily 'fixed'.

 

[DougE]

I will give a report once I take it to the range after replacing the springs. I lube as per S&W's instructions ........ rack the slide a few times and wipe off the excess.