kdmoore Posted November 7, 2005 Share Posted November 7, 2005 Looking for a little advice fitting my 40 round mags. I picked up a few from CTD, and they are tight in the magwell and don't drop free (as expected, picked them up with advice off this board). On the bright side, they will feed everything that I've manually fed thru. So it's time to hit them with a little sandpaper and maybe a gentle squeeze or two from the bench vise. Anyone have a pic or two they are willing to post? Any advice on areas to concentrate on? Lastly, anything to be careful of? Thanks in advance. Link to comment Share on other sites More sharing options...
wsimpso1 Posted November 7, 2005 Share Posted November 7, 2005 I do not like the idea of bending mags that work until you know that mags are too wide. Check the width of your mags and your mag well and then go find the government specs (DIY forum on AR15.com is where I think that I found the drawings). Make decisions after you do that. I currently have a rifle that is undersize at the back, and while it works fine with my 20's, I have some in-spec 30's that do not drop free. Billski Link to comment Share on other sites More sharing options...
Mickster Posted November 7, 2005 Share Posted November 7, 2005 Not sure if the parkerized 40 round steel mag I have is is a CTD or not, but it not only wouldn't drop free, I could barely get it into any of my AR's. I smeared magic marker all over it to find the high/tight spots, took a flat file, and kept filing and checking until it would drop like it's supposed to. It has worked flawlessly for several hundredf rounds so far. For an $18 mag, I couldn't be happier. Link to comment Share on other sites More sharing options...
George Posted November 7, 2005 Share Posted November 7, 2005 As long as you don't mess with the areas where the parts for the mag catch and the bolt carrier latch reside, just get a dremel and do the work on the magwell. I hogged the heck outa' mine and made my own funnel magwell down there. You do not want a total funnel where the mag only latches in at the top and pivots all over the place because you sloped the well all the way up ;-) Basically, it's just creating some extra clearance where contact is tight and beveling the square protrusions near the mouth that catch the mag on the way in. I don't think messing with 40's that work 100% is a good idea either. I have heard said that re-squaring or re-shaping mags in a vise, or with a mallet is a good thing. I am not sure if I agree. I would however do as billski says and measure and compare first. Once you have an accurate assesment of whether it's casting seams or extra metal in the AR well, magazine finish thickness, or outa' square mag bodies, then you can make a good decision on whether to grind metal from the AR/mags, or just re-shape the mags. Me, I'd grind on the well some if the mags aren't way outa' square. -- Regards, Link to comment Share on other sites More sharing options...
kdmoore Posted November 7, 2005 Author Share Posted November 7, 2005 I do not like the idea of bending mags that work until you know that mags are too wide. Check the width of your mags and your mag well and then go find the government specs (DIY forum on AR15.com is where I think that I found the drawings). Make decisions after you do that. I currently have a rifle that is undersize at the back, and while it works fine with my 20's, I have some in-spec 30's that do not drop free. Billski Thanks, My lower is a bushmaster, so I'm sure it's in spec Seriously, it's fit numerous 20's, 30's (USGI and some cheapo's). I'd guess it's ok, but never hurts to check. George, Gotta admit that the idea of me + dremel + valuable object leaves me a bit queasy. I'll look at it to see how bad I could mess things up ... I like the idea of extra room in the well, but had never even thought of carving it out. Hmmm. Most likely, I'll be marking the mags (thanx Mickster). Much rather regret messin up a $13 part than a lower. And if I grow fearless, I can work on the magwell next. Link to comment Share on other sites More sharing options...
mhearn Posted November 7, 2005 Share Posted November 7, 2005 kdmoore Got the same problem with some new 30 rnders from Brownells in my Bushmaster. I started grinding the other night but I'm not there yet. I hope someone can direct us to certain places. The black marker sounds like my next attempt. MHearn Link to comment Share on other sites More sharing options...
George Posted November 7, 2005 Share Posted November 7, 2005 BTW, I use Thermolds exclusively in my front line competition rifle and have never found them to have any trouble dropping from any AR I have. It's the metal body GI type mags that seem to have drop-free issues. -- Regardsm Link to comment Share on other sites More sharing options...
Sestock Posted November 8, 2005 Share Posted November 8, 2005 I just had this trouble with some new Brownells mags. Before you start grinding on the mags, check the back of the mag. The weld of the metal overlap is probably a little out of spec. On mine the metal had a little gap, I just took a tack hammer and peened the back a little, solved the problem completely. Link to comment Share on other sites More sharing options...
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