S&W 439 Magazine Replacement Issues


November 3, 2011, 09:07 PM
I have an 84' vintage S&W 439. I lost one of the factory stock mags. I recently purchased two Pro-Mag (8 round) magazines for Model 439 from MidwayUSA. When the mags arrived, they didn't lock. I ended up paying $40 and got S&W's new single-stack 9 round replacement magazine. ProMags are half the price, little bit lighter and not as well made. The S&W mag locks, recycles OK but sticks out a little at the bottom which is not a big deal. I haven't shot any rounds out of it yet.

In the link below for the original S&W stock mag you'll see a notch marked with the red arrow, this notch is missing from the ProMag magazine. I may be wrong but I think it allows the mag to lock into the frame.


The link below is for the ProMag magazine. I wrote to the manufacturer 3 weeks ago and got no response. Their magazine is shown as a substitute for the S&W 439 mag with a major online retailer and they don't seem to care whether it even fits or locks into the gun. Thanks to MidwayUSA, I got a refund.


For the more tech savy members, is it possible to make a similar indentation like with the S&W mag, so ProMag mag will lock?

Thank you in advance for your comments.

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November 3, 2011, 09:23 PM
I'm surprised that you haven't heard about the running dissatisfacton with Pro-Mags. People have been complaining for years. It seem it doesn't to matter what gun it is for, they are usually inferior to the factory mags.

November 3, 2011, 09:50 PM
I've been out of the loop for a while and haven't kept up with the headlines. For the price, I expected smt inferior but not dysfunctional.

November 3, 2011, 10:06 PM
You can find some used, less expensive factory mags on gunbroker.com when they come up, or new factory mags at higher prices. I have bought several S&W mags there. Just seek out the better auctions.

David E
November 4, 2011, 01:40 AM
That notch isn't where the mag catch locks. Turn the mag over, it's about 1/3 or so down from the top.

If a thing doesn't work at all, then the "great price" doesn't mean much, does it.

November 4, 2011, 09:38 AM
Pro Mag has a well deserved reputation for producing less than stellar replacement magazines.
Put a backorder in here and they will ship you genuine magazines.

Of course you can also go direct to the source,


November 5, 2011, 07:31 AM
David E.

In fairness to ProMag, there were S&W owners who left positive feedback on their magazine at MidwayUSA. The description states it's designed for S&W 39. Midway USA made an error and showed it as a substitute for 439. Among the positive feedback I noticed few 39's and lot of 39-2's owners.

Thank you for the location of the mag catch. I took the hand-guards off from my 439 and located the mag catch - as you mentioned about 1/3 of the way down from the top. With the hand-guards removed the ProMag locked in place fine, almost as flush as the factory stock mag.

The second problem was having to press the mag release button to push the mag into the mag well, otherwise it was catching about where I marked with the arrow;


I used a Dremel tool and tooks some metal off which solved this problem. I was almost happy until I screwed the hand-guards back on, this time the mag had no problem going into the well but it wouldn't lock :cuss:. The S&W 439's original wood hand-covers extend 1/4 inch or so beyond the frame, so the ProMag doesn't push far enough to engage the mag catch. I suppose I could use the Dremel to cut a bigger notch in the mag but not sure if that'll create feeding problems.

I bought a new 9 round S&W replacement mag from MidwayUSA. The original 8 round mag is discontinued by S&W. It's twice the cost of the ProMag but fits into the mag well with no problems, locks with better precision than the original. The only cosmetic issue is the bottom of the mag sticking out 1/4 of an inch beyond the wood hand-guards.

What started as an inventory control issue with MidwayUSA turned into an exercise on how to make a ProMag magazine work in a hand-gun it wasn't designed for :uhoh: MidwayUSA refunded my account and let me keep the mag.


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