jakfrost1 Posted November 29, 2016 Share Posted November 29, 2016 Been working on getting the set of 6 brand new MBX 155mm mags to work in my new STI DVC Open gun with a Phoenix Trinity grip fitted, and having a lot of trouble getting them to work. The first issue was the grip screw(s) spacer/nut rubbing against the mag tube just before the mag reached the fully inserted point. In order to have the mag catch snap into place you had to really SMACK the base plate...HARD. This took some investigation since at first I blamed the positioning of the mag catch inlet on the mag...then the mag catch itself. Both of which I worked on for a number of hours to no avail. Thats when I gave up and began looking for another culprit and discovered the lightest of markings on either side of the mag tube and realized they aligned with the grip screw spacer/nut. The spacer/nut already has a taper on the lower half to provide relief for the stock STI mags ( which work perfectly by the way, but I only have one and needed more mags so decided to try the MBX units since they receive such glowing comments...), and after 5 minutes with a file the MBX mags snapped easily up into place, and released at the tap of the button! Great. Except I was working with the slide removed the whole time. Put the top back on and inserted a full mag to check 'reloadability'...which is fine. Except now the mags don't want to drop out. AND the slide drags so bad it won't go fully into battery without a push, even on an empty mag. I seems like the MBX comes up just a little higher in the well than the STI units and the lips rub on the inside of the slide...is it possible this is the problem? I'm not sure what to do, I don't want to start 're-curving' the mag lips to clear the slide. Kinda frustrated after the $890.00 hit for 6 MBX 155mm mags. Anyone been there, fixed that??? Link to comment Share on other sites More sharing options...
cecil Posted November 29, 2016 Share Posted November 29, 2016 I shoot a STI DVC Open 9mm major pistol... I use both STI mags & MBX mags... no problems what so ever with either brand magazines .. no modifications what so ever with either brand magazines... however I use the OEM grip that came on my DVC... by the way all my mags are the 170 mm mags.. I suspect the problem is the Phoenix Trinity grip is not compatible with the DVC mags... just wondering does your DVC have the same problems with STI magazines ? Link to comment Share on other sites More sharing options...
jetjocky Posted November 29, 2016 Share Posted November 29, 2016 Have you tried a Dawson posi lock mag catch. It helps prevent overinsertation of the mags. Link to comment Share on other sites More sharing options...
teros135 Posted November 29, 2016 Share Posted November 29, 2016 It's not the grip (PT is right to spec), not the mags. My guess is that you don't have the inner grip screw nut pushed fully into the frame and grip, so it sticks out and interferes with the mags. The metal grip is a different animal because it doesn't flex like the plastic one and needs to be fully aligned with the grip screw holes in both the frame and the grip. Take a look at an assembled plastic grip and you'll see where the inner nut is supposed to be. All is good. Link to comment Share on other sites More sharing options...
echotango Posted November 29, 2016 Share Posted November 29, 2016 (edited) My MBX(7) mags rubbed the slide & frame and took a lot to get them to drop. It had nothing to do with the grip and all to do with the mags. Never had a fitment issue with sti mags. When I changed to the evo, nothing changed in regards to mags. Edited November 29, 2016 by echotango Link to comment Share on other sites More sharing options...
ScottieShootz Posted November 29, 2016 Share Posted November 29, 2016 Very weird, pt evo grip here and it drops mbx and sti mags without any issues. Also have a dawson posi mag release installed which I did not make any adjustments to. Link to comment Share on other sites More sharing options...
theWacoKid Posted November 29, 2016 Share Posted November 29, 2016 Hit up Adrian at MBX. He will help you. This sounds like a slight tolerance stacking issue between mag length, notch location, mag release location, mag release, frame tolerance, and slide tolerance. I did notice my MBX mags would kiss the bottom of the slide when inserted hard. Never caused a problem and the MBX's have worked much better across all my guns than my tuned STI's. Link to comment Share on other sites More sharing options...
jakfrost1 Posted December 2, 2016 Author Share Posted December 2, 2016 OK...got 5 of the 6 working after removing the grip 'nut/spacer' on each side and removing material in the same place as the taper that is already there. Not sure the PT grips themselves had anything to do with it, the nut fits perfectly with the 'flat' side in place under the bottom edge of the frame. No idea what the problem is with #6, but with or without ammo, it causes the slide to drag so bad it only closes halfway going into breech. The lips measure within a thou of the other 5...guess I could try to eyeball the curve and start beating on them. The other problem is how the f--k does anyone get the bases off of these suckers. The bottom of the spring fits so tight in the base it is almost impossible to slide the base far enough to put pressure on the spring to release the base. I had to pull 2 of the springs up thru the top of the mag just to get them out. Didn't do the spring any good thats for sure. Are there after market base plates for these? Is there some secret trick to disassembling MBX mags? The bases otherwise work well with the little 'pin' stop to prevent them from coming off, but it would seem they are really not necessary, given they are almost impossible to pry off anyway. Link to comment Share on other sites More sharing options...
ScottieShootz Posted December 2, 2016 Share Posted December 2, 2016 (edited) On two of mine the spring locks in tight and does not want to pop loose when taking the basepad off. I ended up finding a thin flat blade screw driver does the trick with the basepad slid half way off to pull the spring free. More complicated than my dawson pads that is for sure. I have read of a few people beveling the inside lip to all the spring to pop easier. can you check body dimensions on your 6 mags and see where the pinch part would be. I know Adam in one of the atlas videos showed tapping the body with a nylon hammer to narrow the mag a bit. Edited December 2, 2016 by ScottieShootz Link to comment Share on other sites More sharing options...
Hunter1998 Posted December 3, 2016 Share Posted December 3, 2016 (edited) Only issues I had with my MBX mags was the overall length in front. One pistols feed ramp was slightly extend and was hitting causing mag to roll inward causing feeding issues. Trimmed mag and never had an issue again. I did replace mag springs to grams on my 40 mags. Will do the same when my 9mm mags springs weaken. i have no issues removing base pads. I often clean mags during a match Edited December 4, 2016 by Hunter1998 Addition info concerning question Link to comment Share on other sites More sharing options...
jakfrost1 Posted December 4, 2016 Author Share Posted December 4, 2016 On 2016-12-02 at 10:38 AM, ScottieShootz said: On two of mine the spring locks in tight and does not want to pop loose when taking the basepad off. I ended up finding a thin flat blade screw driver does the trick with the basepad slid half way off to pull the spring free. More complicated than my dawson pads that is for sure. I have read of a few people beveling the inside lip to all the spring to pop easier. can you check body dimensions on your 6 mags and see where the pinch part would be. I know Adam in one of the atlas videos showed tapping the body with a nylon hammer to narrow the mag a bit. Link to comment Share on other sites More sharing options...
jakfrost1 Posted December 4, 2016 Author Share Posted December 4, 2016 I can't move the base on at least 3 of them to get more than 1/4 of an inch opening despite my best efforts. I finally put the base against the top edge of my bench and pushed down with all my weight which forced it to open to about 3/4", then I could do as you did and get a flat blade in the opening to depress the spring enough to force the pad off the rest of the way. Very frustrating when at a range with a sandy floor and little time between squadding to fiddle with sandy mags... I'll check the body dimensions as you suggested but I have used tracer ink to mark the bodies where they might be rubbing on the slide. The mag goes into the well with no resistance but the slide drags to a stop about 1/2" from the barrel when released with the slide release...? Unusable, for now anyway. Link to comment Share on other sites More sharing options...
Bkreutz Posted December 4, 2016 Share Posted December 4, 2016 On 12/2/2016 at 7:16 AM, jakfrost1 said: OK...got 5 of the 6 working after removing the grip 'nut/spacer' on each side and removing material in the same place as the taper that is already there. Not sure the PT grips themselves had anything to do with it, the nut fits perfectly with the 'flat' side in place under the bottom edge of the frame. No idea what the problem is with #6, but with or without ammo, it causes the slide to drag so bad it only closes halfway going into breech. The lips measure within a thou of the other 5...guess I could try to eyeball the curve and start beating on them. The other problem is how the f--k does anyone get the bases off of these suckers. The bottom of the spring fits so tight in the base it is almost impossible to slide the base far enough to put pressure on the spring to release the base. I had to pull 2 of the springs up thru the top of the mag just to get them out. Didn't do the spring any good thats for sure. Are there after market base plates for these? Is there some secret trick to disassembling MBX mags? The bases otherwise work well with the little 'pin' stop to prevent them from coming off, but it would seem they are really not necessary, given they are almost impossible to pry off anyway. Don't know why you're having these problems, my MBX mags all work great and the bases slide off with little effort. Curious, MBX has some videos on their website, have you looked at them. Maybe you're trying to put the bases on from the wrong side?? The end with the pin is on the front side of the mag tube. Just a thought. Link to comment Share on other sites More sharing options...
ScottieShootz Posted December 4, 2016 Share Posted December 4, 2016 15 hours ago, jakfrost1 said: I'll check the body dimensions as you suggested but I have used tracer ink to mark the bodies where they might be rubbing on the slide. The mag goes into the well with no resistance but the slide drags to a stop about 1/2" from the barrel when released with the slide release...? Unusable, for now anyway. Wow, weird you have a couple issues going on. On the mag bodies, when there are no springs do the base pads slide on and off no problem? Just to rule out the lower rail lips aren't bent or anything making it tight. They should slide on and off no problem. Verify as well the locking pin on the front is fully out of the way for removal. With the slide drag, does the tracer ink show what is contacting on the mag body? Is it the underside of the slide is hitting? Link to comment Share on other sites More sharing options...
jakfrost1 Posted December 5, 2016 Author Share Posted December 5, 2016 (edited) Thanks for the replies...the base pads only go on one way, well you could put them on backwards but the locking pin won't clear the forward edge of the lip on that side. The locking pin only works if the base is installed correctly. The spring's have a squared off 'bottom' or 'last' coil, which fits perfectly into the machined space inside the base pad. That seems to prevent a couple of the bases from moving as they should. The bottom of the spring is captured in the machined relief in the base pad, or so it seems. As far as the dragging slide and mag #6 goes, I can't see for the life of me where it is dragging on the slide. I thought it might be the follower since with no ammo loaded they point upwards pretty good. But even with the mag stripped out, no guts, no base even...it still drags. And with a full mag the slide moves forward even less...Guess I'll have to take it to a gunsmith with X-ray eyes, haha. PS Just finished watching a few Atlas Gunworks, ( Adam ), videos. One of which was specially for the DVC and MBX mags fitment issue. Apparently my problem is far from unique. Reassuring. But at least the video gave me some ideas to perhaps work out the problem when I get home...in the end he used a plastic mallet to beat the bugger into submission! I'd be tempted to beat it flat, haha Also I've been using a regular black Sharpie to try and see where the problem is but he seems to use a blue one, is that some kind of machinist special dye marker? Edited December 5, 2016 by jakfrost1 Link to comment Share on other sites More sharing options...
theWacoKid Posted December 5, 2016 Share Posted December 5, 2016 1 hour ago, jakfrost1 said: Also I've been using a regular black Sharpie to try and see where the problem is but he seems to use a blue one, is that some kind of machinist special dye marker? Probably dykem. Link to comment Share on other sites More sharing options...
jakfrost1 Posted December 8, 2016 Author Share Posted December 8, 2016 (edited) OK, I think I get it now, there is a reason why 'Production' is called what it is...cause when you move to 'Open' it should be called 'Custom'. Because you or your gunsmith WILL BE spending time and $$$ on the gun, probably sooner rather than later. I bought my STI DVC Open 9 Major from a fellow shooter who sent it brand new straight to an excellent smith to have it 'tuned', before he ever shot it. He ran out of money. I bought the gun with 300 test rds fired thru it and a new RTS2 and a PT SS grip. But only one elderly STI mag. Did a bunch of research and decided on the MBX 155's from Adrian Cobb. I don't have a gunsmith in the same area code so did the Aftec extractor myself, and since NONE of the 6 mags would even latch in the mag well I began the journey to get them all working. A new mag catch and hours of testing, filing, and beating with a plastic mallet and now all 6 reload easily and fall out when released. I reset the trigger to 2lbs 4oz from the 1lb 10oz it came with...and I think I'm good to go. Tried 300rds the other afternoon and it runs like a top using 8.2grs of 3N38 behind a Zero 124JHP. Point being, Open seems to be more like 'Custom', little did I know! But on the bright side I certainly do know the gun 'inside and out' by now, haha. PS, still have to figure out how to get these darn mag base pads off easily...work in progress. Edited December 8, 2016 by jakfrost1 Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted December 8, 2016 Share Posted December 8, 2016 8 hours ago, jakfrost1 said: when you move to 'Open' it should be called 'Custom'. Because you or your gunsmith WILL BE spending time and $$$ on the gun Ten years ago, I bought a TruBor which had been slicked up by Brazos and except for one mag which didn't work, the gun was 100% reliable until I had to replace springs. Link to comment Share on other sites More sharing options...
lightfighter363 Posted December 16, 2016 Share Posted December 16, 2016 My MBX has no problem with my open DVC. Link to comment Share on other sites More sharing options...
Ultimo-Hombre Posted December 31, 2016 Share Posted December 31, 2016 Good work figuring it out! Mag tuning is black magic stuff sometimes. Just when you think you know what you are doing..... you don't. I had an MBX tube that wouldn't drop, tried all sorts of stuff, because I think I'm smart, and forum group think. Turns out that when I had tried to squeeze the mag to address what I thought was too large of a front to back dimension I actually took it out of square. Very slightly but just enough to make it totally phukked up. Henceforth, the advice of "call up the manufacturer first" became my SOP. Link to comment Share on other sites More sharing options...
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