AR15 MAG LOCK HELP PLEASE!!!

[Wicked One]

I Know there's a issue, But not sure what the Best way to correct this would be?
After installing my CMMG LPK & Stock on my newly made lower I went to slide a Empty Mag into it and WTF..... It will NOT lock into place! After 2 days of looking at it, re-checking all my CNC Mill job measurements against a Mill-Spec AR15 lower Blue Print I have, everything "Seems" to be in spec.
I have (2) different Brands of Magazines, Magpul & Tapco...... Neither will Not slide in far enough to line up the lock slot in the Mag(s) with the Mag release catch on my lower??
So what to do Now?.... I have came to a few possible solutions, But b4 I go and FK-UP something I thought I would ask for help. I am pondering on two different solutions;
1. Opening up the locking Slot on all of my Mags. Another words just making the Slot larger so that the catch falls into it and locks. (Problem I see in doing this is it makes My Mags only work in my AR and any further Mag buys would need the same "Fix")
2. Shaving down the Block that sticks out and locks the Mag into place on the Mag catch itself. I would basically have to take a 1/4-1/2 of the block off(Just grind it flush)to get it to lock into the Mag slot.
I am Posting up a Few Pics to help all better understand what I am talking about(Hopefully). If ANYONE has ran into this and has more insight on how I can fix this Problem PLEASE let me know?
Again, ANY AND ALL help and or Suggestions would be Greatly Appreciated!

[Wicked One]

More Pics....

[jfifer]

It just seems like your magwell is tight dude. Dont worry about it! Use an expo marker, color the mag. Then shove it in. Find the "high spots" in the well and file/ sand them lightly

[jfifer]

Your mag catch could be way too tight too. I did that once too.

[mycrstuff]

Try a non Tapco mag. The Tapco mags run a little big.

[Ed_Hazard]

Looking at this pic it appears that the slot cut tapers from right to left, which puts locking tab above the locking slot in the mag. If you have a set of calipers chheck the dimensions.

[jfifer]

He did, magpul

[Wicked One]

It just seems like your magwell is tight dude. Dont worry about it! Use an expo marker, color the mag. Then shove it in. Find the "high spots" in the well and file/ sand them lightly

Thanks, But the Mag Slides all the way to were it Hit's the First Rib on the Magazine and even push's the BCG Stop up. There's NO WAY it can slide up any further??? (Please see all the Pictures)

Your mag catch could be way too tight too. I did that once too.

Thanks, thought that as well, But I took the BB Mag Catch completely out(Via the Picture), Slide the Mag ALL THE WAY IN and then slid the Mag Catch back into the lower and it Still will NOT lock the Mag into place. It's like the Notch in My Mags are cut to low??(But I know this cant be the case as I have tried 2 different Brands and both have the same issue)

Thanks for the Help and input..... Please keep it coming.

[Wicked One]

Looking at this pic it appears that the slot cut tapers from right to left, which puts locking tab above the locking slot in the mag. If you have a set of calipers chheck the dimensions.

Thank you, I seen that as well, I Mic'd it 3 times and I have the Correct .250" throughout the Slot and .9375"(+/-.0035") from the base of the Mag slot to the top of the Receiver all the way down. I think it's just an optical illusion

[Wicked One]

Try a non Tapco mag. The Tapco mags run a little big.

He did, magpul

Thank you..... Correct, I have tried Both Magpul & Tapco.

But let Me clear something up that seems people are thinking....... I realize mags can be Tight Sliding in & out of the Well. Mine is a little tight too, BUT this is NOT what the Problem is. I can slide "Both" Brands of Magazines all the Way up into the magwell to the point that the Follower(s) are Pushing up on the Bolt Catch(So I know there going all the way in)and the Bottom of the magwell is hitting the First Rib(s) on both Mags.
It's like I mentioned above, it appears like the Slots are not Cut correctly(Which common sense tells me otherwise), OR maybe my Mag Catch Block(the part that pops into the mag lock hole) is too large???
IDK, But this is Driving Me Crazy!!!!

[buellster]

If your p-mag is in all the way the diagram of a bullet on the side of the mag that says: "5.56X45" should be half exposed at the top of the receiver.

[jfifer]

Damnit this is driving me nuts. Freakin internet diagnosis. Where are you located? Im on mobile

[TahoeTim]

I had the same issue on my CNC80 with 10 round mags. None of your photos show the area where the mag hits the back of the mag opening. Mine was hitting at the bottom, not allowing the mag to slide up quite far enough.

Look at the back edge of the mag well and see if the mag hits there. Picture 4 and 5 looked like mine. Pictures 1 2 3 all look like the mag is too deep in the well. Can't help you there.

[buellster]

I had the same issue on my CNC80 with 10 round mags. None of your photos show the area where the mag hits the back of the mag opening. Mine was hitting at the bottom, not allowing the mag to slide up quite far enough.

This is what I'm assuming is the problem. Try a metal mag. They don't have stops to hit the bottom of the well.

[TahoeTim]

Good point. I have a 30 round shell (since a complete mag would be illegal) and it slams in no problem. I chose to grind off the plastic on my mags but I may rethink that since borrowing a mag won't work. I guess I'll dremel the mag well so anything fits.