Hey fellow shooters...I picked up some 20 round mags from each source, and as I do with every new mag, pulled them apart right out of the pkg. carefully checking them over for burrs (none on either) cleaning them inside and out for grease, dirt...ect. (the W mags had alot of dust inside) closely compared the shape of the feed lips (identical) follower; here there is some difference...the CMI follower being polished smooth, the W mag rough parkerizing...but the edges of the followers on both had no burrs...I laid the micrometer on both and they are identical specs there. So to me, the main difference I see is in how rhe W mags are finished in a very rough, thick abrasive parkerizing inside,so I cleaned, polished with a dremel, and VERY lightly lubed them both. The springs seem to be equal, but i had a few spare GI ones laying around brand new to switch out if I had problems.
 Bottom line? I took both to the range after that, and they both worked fine in my M1A Scout Squad...I only load 18 rounds...and I shot both steel cased and brass cased ammo...no problems.
 Conclusion? I will only purchase CMI mags or GI surplus mags from now on...but having said this, the W mags seem to work ok for me, so far. I see them as range mags, or for spare parts...how long will the springs last? The feed lips? Don't know...but for what they cost, are acceptable. I would not leave W mags laying around loaded for a long period of time. Also if you change out the springs with GI ones, you may solve any potential problems there...just my .02

I am not aware that Taiwanese mags are marked with a "W".  A "W" marked mag is supposed to be a USGI mag made by Westinghouse.  The question as to whether or not they are USGI mags is easy if ones knows how to do it.  Simply count the spots welds up the front.  The USGI mags have 12+1(the +1) is the one next to the latch hole.  The welds are uniform in size and spacing.

Same here, but don't overlook Norinco & Poly Tech mags, they are excellent.

The W marked mags have been counterfeited for years.  Even down to fake counterfeit wrappings to fake usgi wrappers.

Yes the body of they fake W stamped are okay but the spring for whatever reason is longer. If you replace the spring it is good to go. The problem with the W stamp is that yes they do function but given certain circumstances of use, the mag fails such as multiple rounds flying off. If you touch the w stamp just right all the rounds will spray out wildly.

My guess as to why they made the spring longer is because it is made from cheap metal so they have to make it longer to give the same tension.

CMI mags are only 5 bucks difference compared to the fake W stamped ones. With that said if you factor in the fake mag and new spring they'd cost the same as just buying cmi from the get go.

My thought is buy as many cmi mags as you can. M1a mags are not as widely produced and if cmi decides to limit or cancel civilian production then you're screwed. Learning from the era of the AWB most m1a owners know to buy from the best especially while they're afforable.

Remember cmi used to be subpar mags... That was the pre AWB days when some of the best mags were made. Now they're considered the best because they're the only one standing. Cmi produced mags for the government during the 90s for their deck guns. When the war kicked off cmi was contracted to produce more mags which gave them the upper hand.

I will look at my Taiwan mags . I do not remember any being marked

my point was just that with a little care the fake W mags can be servicable range mags.

On a side note about the polishing... "0000" Extra Fine steel wool will make very short work of polishing rough metal surfaces... just do a test spot some place.

I use it to polish ( burnish ) all sorts of stuff ... even rough buffer tubes. The 0000 will just burnish the surface. Try it, you'll see.

Your local hardware store should have it..... remember 0000 only ! anything "rougher" will make a problem.

I have a couple of these mags and the mag spring is from an AR10 and the follower was a cheap imitation.

The mag bodies were in fact made by CMI as the welds etc matched. I simply replaced the springs, follower, and bottom plate with CMI parts. They work great


Check out Differents thread on the main M14 page.