WE M4 mags not fitting properly

[W0lf]

I googled, and searched around briefly and found nothing that helps me any.

a while ago i bought a we scar off someone, it came with a few leaky mags.
recently i took them apart and resealed them, added new orings, etc.
and now they wont seat correctly. in the following pics the black mag shows how it fits snugly, the tan one sits too high, and the gas release port on the mag collides with the brass tube.
the last pic shows one of the mags that wont seat properly inserted. the bolt will travel but not smoothly.







any help would be greatly appreciated.

[Dire_Wolf]

when you resealed, did you also do the o-ring in between the gas port and the knocker valve? or add the credit card piece in there? if so, that might be your problem... also, check to make sure the tab on the inside of the bottom plate, where the screw goes through, isn't bent up....

might try swapping shells between the mags, see if that fixes it...

[W0lf]

Originally Posted by Dire_Wolf

when you resealed, did you also do the o-ring in between the gas port and the knocker valve? or add the credit card piece in there? if so, that might be your problem... also, check to make sure the tab on the inside of the bottom plate, where the screw goes through, isn't bent up....

might try swapping shells between the mags, see if that fixes it...

yes, i sealed all the points that generally leak in these mags. i didnt do the credit card thing, i wouldv taken them off to try and see if that worked.

also, the tabs arent bent up, because the top of the shell meets up with the rim of the inner casing. the only difference between the mags that i can actually see, are where the bolt catch lock flips up, a tab behind it is broken.

up untill i took them apart, 4/6 would fit fine. the other two causing the bolt to not slide proper.
now after servicing them, only 1 mag will properly feed and fire.

dont know if this helps, but when i gamed my we scar with them last sunday they all worked fine through the scar, but once or twice i went to fire and the mag just let out all the gas. i think the valve just stuck in place from maybe a piece of the sealant i used coming free. it only happened the one or two times, and hasnt happened since while plinking in the basement.

rather shocking when it happened though, scared the hell out of everyone, they thought i had some type of grenade.

[Dire_Wolf]

hmm... dunno what it could be then... I have a few mags with the tabs behind the bolt catch parts broken off, but they all work just fine in my scar... maybe check for the top plate being level? if anything got bent upwards or downwards during installation..

i'd agree with the valve getting stuck, i'd vent the entire mag a couple times outside of the gun (or take the lower off, put the mag in, pull trigger) to get rid of sealant crap...

[W0lf]

thanks man i released it just with a pencil, free of the gun once or twice, didnt know that just using the lower was safe, thanks though, now i know.

i was thinking if anything maybe i just have to dremel off some of the plastic where the gas port is, lowering it just 1-2mm. want to get a few other opinions of what it could be before i do something drastic.

having a broken scar and now only 1 working mag really puts me on the spot untill i can afford 5-8 new mags. :\

[Dire_Wolf]

Personally, I'd grind off the top of the shell a 1/2 mm at a time or so, and move the screw tab down in the lower to accommodate... Instead of messing with the feed lips and seal and what not... But perhaps a full disassembly of the mag would help?

On second thought, grind a bit of the top on the mag stop hole, lowering where the mag release holds it

[W0lf]

Originally Posted by Dire_Wolf

On second thought, grind a bit of the top on the mag stop hole, lowering where the mag release holds it

iv thought of this aswell, im still gauging info and staring at them assembled and dissassembled. i wont jump the gun and just start gnawing away at stuff.

[Ross]

It doesn't make sense that they don't fit. The only time my mags didn't fit was when the feed lips screw wasn't tight enough, and the mag wouldn't push all the way in.

[coach]

wait. OP, did you do the blue gasket sealant on the mags? I've only ever used sealant to seal the rear plate of the mag, similar to z0ng's DIY. did you use sealant around the feed lips too?

Before you grind down the feed lips, disassemble it again and see if you install everything properly. I don't understand how it could sit a few mm's higher if everything was done correctly. check all the screws and make sure they are snug. I've never taken the top portion apart yet but could the feed lips be in backwards?

[Dire_Wolf]

Originally Posted by W0lf

iv thought of this aswell, im still gauging info and staring at them assembled and dissassembled. i wont jump the gun and just start gnawing away at stuff.

no no, for sure... i wasn't suggesting jumping to grinding, i'm just providing possibilities a la brainstorm

and i agree with coachster and ross.... i simply can't conceive how it could possibly fit and work before you did the sealing, and then not work after the sealing....

I personally did 7 propane mag seals this week, and none of them ran into that problem with my scar...

edit: looking at that third picture, i remembered something from when I was sealing my mags... if you have the lower receiver out when you put everything in, the mag WILL go a bit further than it would otherwise, because there isn't a brass tube to stop it... take another look at the difference between the two, but pull down on the mag after you insert it, to make sure the mag catch is what's keeping it in place...

I think there might be an irregularity in the feed lip gas port rubber... it looks slightly higher compared to the black mag... but that shouldn't make a difference, as that rubber should compress on mag insertion...

[W0lf]

last night i dremmeled about half a mm out of one mag catch. worked like a charm and still seats in my scar proper aswell. a few weeks ago i made a decision to hold off on getting a new pistol and replace all my mags so if i would have screwed something up, it wouldnt have made me too mad.

my original thought was to grind a bit out of the magazine catch, i just figured after a bit more thought that sanding the gas port mightv been a better idea.
glad i took a step back and gathered some opinions,
so thanks.

oh and ya i did one mag with blue sealant, then on a different did a thin coat of rubber sealant/cement, the blue stuff didnt seem to be thick enough in my opinion, same with the glue i tried it on one mag first to make sure it would just blow glue out everywhere or something and theyv survived a full day of gaming plus the most plinking iv done since september.

and about the mags sitting higher with no upper receiver, in both of those pics i had just let the mag click into position and took the picture as low as it would sit. i still havent figured out how this happened, and how it went from just a couple mags, to all of them. i checked my entire m4 to make sure nothing was bent, and installed properly. everything was fine.
im pretty upset after gaming the scar last week and it failing so much, now i fix my m4 and it feels and shoots x100 harder than the scar.

[coach]

Originally Posted by W0lf

last night i dremmeled about half a mm out of one mag catch. worked like a charm and still seats in my scar proper aswell. a few weeks ago i made a decision to hold off on getting a new pistol and replace all my mags so if i would have screwed something up, it wouldnt have made me too mad.

my original thought was to grind a bit out of the magazine catch, i just figured after a bit more thought that sanding the gas port mightv been a better idea.
glad i took a step back and gathered some opinions,
so thanks.

oh and ya i did one mag with blue sealant, then on a different did a thin coat of rubber sealant/cement, the blue stuff didnt seem to be thick enough in my opinion, same with the glue i tried it on one mag first to make sure it would just blow glue out everywhere or something and theyv survived a full day of gaming plus the most plinking iv done since september.

you aren't suppose to use that much sealant. you are using just enough to fill the gaps that the original seals/orings don't cover plus adhering the seal/oring to both the mag and back plate.

did you let them cure? you need to let them sit for at least 3 days in cooler temperatures. in the summer it can cure in as little as over night. my rule of thumb is three days and I will give it a tiny, less than half second, blip of propane from a near empty can. this gives a slight bit of positive pressure but doesn't disturb the sealant causing it to pull away from the seal. if you gas it too soon, do one or two complete fills with propane and blow out all the bits. this really only happens when it's filled prematurely not allowed to cure.

I don't know where else you used the sealant but I'm sure you did something wrong reassembling it. there is no way that the feed lips would end up a millimeter or two higher than what they started at.

[W0lf]

uh, theres barely any sealant visible whatsoever, theres a very thin coat of it, probably just a molecule thicker than the blue stuff. the mags are functioning fine now, there are no more problems. i let the stuff cure for well over 4 days just to be extra certain it sealed properly.

i took the mags apart numerous times to make sure they were together correctly. there obviously isnt much too them to get wrong. remember, when i got a few of these mags second hand from someone, they wouldnt fit in my m4 to begin with.

so it wasnt just my doings, to all of them atleast.

anyhow the problem is solved, all the mags except one fire 110%, theres only one that keeps chopping bbs after a few shots, ill look into that one later.

[coach]

alright. I hear ya.

[Dire_Wolf]

Originally Posted by W0lf

uh, theres barely any sealant visible whatsoever, theres a very thin coat of it, probably just a molecule thicker than the blue stuff. the mags are functioning fine now, there are no more problems. i let the stuff cure for well over 4 days just to be extra certain it sealed properly.

i took the mags apart numerous times to make sure they were together correctly. there obviously isnt much too them to get wrong. remember, when i got a few of these mags second hand from someone, they wouldnt fit in my m4 to begin with.

so it wasnt just my doings, to all of them atleast.

anyhow the problem is solved, all the mags except one fire 110%, theres only one that keeps chopping bbs after a few shots, ill look into that one later.

heh... and now chopping BBs is the opposite issue.. too low :P

that needs the credit card fix lol