I bought six of these mags from CDNN hoping that they'd be an inexpensive means to extending my shooting time between reloading.

So I took them out to the range this morning only to have each and every one of them FTF the final two rounds. I tested each mag twice and they failed each time...once with five rounds still in the mag! Manually cycling the action I could see bolt slide right over the rounds.

Luckily I brought my steel Stoner mags so the day wasn't a total bust.

I've sent off an email to CDNN to see about getting a refund or some form of exchange.

As a side note, my newly installed Geissele SSA trigger is excellent. I look forward to going back to the range with a set of fully functional mags next time.

I have quite a few Thermold 20 and 30 round mags that work well in my S&W lower/Daniel Defense upper and my ArmaLite. The 20s almost always work, never heard of problems. Haven't heard anything before about the 10rders but you might try them in another AR.

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US Army 1966-69, VFW Member

My 20's and 30's work well. Haven't had an issue. The tens are just 20's with a block in them I think. If you look at the bottom of the mag right in the center of the bottom is a round hole with a kind of plug in it. If you take a bullet and push on that and slide the bottom forward you can see if there is anything that might be hanging up the spring maybe a bit of flashing on the plastic block. I dont know but it is worth a look, are you in a state where 10 round mags are all thats legal? cause you might also trim that block down or take it out and see if it still has the problem. But if your in a 10 round state (I'm sorry first) it could have to do with the block because I have been waiting on my 20's to mess up and they havent. But CDNN has been good to deal with for me, they have stood behind their stuff.

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Grover Oathkeeper

I only have the one AR and didn't feel comfortable asking strangers to try out my mags. lol.

The 10 rounders are not blocked 20s, but actual, short 10 rounders. I haven't been looking for blocked hi-cap mags since I've been shooting mostly from a bench and don't want the mag hitting the table.

I bought them last week for $6.99 each, but I see today that they're on sale for $4.99. haha. The funny thing is that they actually fit in the Sport better than the steel 10 round mags I have (one factory and three Stoner). The steel mags jiggle a bit, but the polymers click in nice and clean.

Can the springs be stretched out to add more tension, or is that a bad idea? I should have tried it out at the range this morning, but storm clouds were rolling in and I left just before it started to rain.

BHarada...try stretching them..also if call CDNN I got a refund when my Thermolds went on sale the day after I paid for them. I noticed when I took them apart that the springs although they had more coils than the USGI mag I dissassembled at the same time the wire wasnt as heavy so I think that when I find rebuild kits on sale I am going to pick some up. Just for the fact the the mags work well now but maybe with some heavier springs they might work better longer. Good Luck my friend!!! Also how are you shooting from the bench where the 20's would hit but the 10's dont. I shoot off of a bipod and not a real tall one, and was shooting off of the front of a Caldwell Nxt rest. My Thirty's dont just hit they become a third leg but the 20's seem to work real well and they are shorter than a milsurp mag!! Just asking!!

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Grover Oathkeeper

I tried stretching one spring out a full coil length. I put it back together then took it apart about an hour later to compare it to the stock spring and it had returned to its original length.

Hopefully CDDN will offer me a refund as they don't have any other 10 round mags in stock. I'll be ordering some steel mags from 44mag.com in the near future.

As for the bench shooting, I'm using a Caldwell Deadshot sandbag. Using just the front rest bag the 10 rd mag is less than an inch off the table top—all my 10 round mags are shortys. When I first got to the range I was using the bag on top of a wooden block that the range provides, but I was getting too much shifting with the combo so I just started using the Caldwell alone.

I can see why bench shooter like to an adjustable rest, but that's too much gear to have to lug out of the parking lot to the firing line. haha

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- Bill

The 10 round Thermold mags are complete junk.

Sorry you bought them. Stick to known good ones; Pmag, Cproducts, Lancer, USGI- there are quite a few decent ones. But for those particular units, they are just not dependable.

The 20 rounders work perfect in my Sport, great for a cheap mag. Sorry to hear the 10 rounders have problems. Just guessing, but since the problems are with the last 2 rounds, sounds like the springs aren't putting enough upward pressure when the mag is nearly empty. If you were upable to stretch the springs, could you swap them out with some other ones you know that work? Just for an experiment, see if you can use one of the springs from the steel Stoner mags in the Thermold and then try it at the range to see how it does.

The earliest I can make it back to the range would be this weekend, but I hope CDDN will have taken care of the issue by then. Between Midway and 44mags.com I can get the 10 round steel mags for <$12.

I wish Amazon would sell more mags, but the only one I can find are hi-cap PMags or a 5-rd Tapco. I'm spoiled by the Amazon Prime shipping.

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- Bill

Well, just got off the phone with CDDN and they'll be sending me a return label and issuing me a credit for the six mags. The guy I spoke with said that there may be an issue with the feed angle on the 10-rd mags, but I don't see why that would only affect the last two rounds in the mag.

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- Bill

Yeah...Bill that is weird, I dont have the problem with the bigger ones but I am glad that I dont use the 10 rounders, although it would help conserve ammo, having to make more mag changes.

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Grover Oathkeeper

Well, having 10 rd mags that misfeed after 8 shots will definitely slow you down. I think I spent as much time clearing my rifle and fiddling with the mags as I did actual shooting.

I was at the range for 2.5 hours and only managed to shoot 40 rounds of 22LR and less than 150 rounds off .223...all because of misfeeds (I need to do the ejector adjustment to my 15-22) in both guns.

Well, I placed an order for more steel mags from Midway this morning. If they do as usual and get them out today I should have them by Friday.

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- Bill

trash them and count it up as life lessons!!!!!!
I have a 30 rounder I just trashed!!!!!!!!
I have had several conversations through emails with them(thermold)
and they wont even take it back.
in general anything that looks to good to be true. (good price) is to good to be true.
just my two cents.