AR15 Takedown issue

[Lallop]

Hi all...!

im having a boring issue, its currently on my AR308

so what happens is; i just installed the takedown pins on my AERO lower and once i drop the upper in and lock the FRONT takedown one, somehow its getting misalligned........causing the magazines to get stuck in place, and making it impossible to

insert/remove a magazine with the bcg installed.

HOW THE HECK IS THIS POSSIBLE? someone here is making their components out of specs? it is the first time im running thro a similar issue with more than 9 builds. Any suggestion? get a new pair of takedown pins?

from the naked eye is virtually impossible to spot any weird canting of the upper to cause this problem once the takedown pin is closed

just WTF, please help :S

[SomeOtherGuy]

Pictures help. Are both upper and lower made by Aero Precision, or is the upper a different brand? I ask because not all .308 AR parts are compatible with each other.

Also, since this involves a .308 AR it's a perfectly legit post in this forum. I would delete the sentence implying it's in the wrong place just for attention.

[Lallop]

they are matching AERO upper and lower!!! thats why im going nuts!

[SomeOtherGuy]

Yeah, that would bug me too. Without photos I'll need a really detailed description. Are both front and rear pins* installed in the lower and being put through the respective holes in the upper's lugs? Is it difficult to close the two halves, or to push the rear takedown pin to the closed position?

*the front pin is the pivot pin and the rear is the takedown pin. The terminology doesn't usually matter and they both get called takedown pins all the time, but to be sure I'm understanding the problem be precise.

What kind of magazines are you using? How far will they insert before being blocked?

Just to confirm, the same magazines will go in and latch properly when the lower half is separated?

[daddyusmaximus]

Gonna follow this, just in case. I'm collecting parts for a .308 build. (also Aero)

[Lallop]

Im using 25 rounds p mag, i have another AERO 308 build and they fit great and drop free when releasing the mag catch.

i have tried with the lower alone (no upper inserted) and the mags fit as they should & drop free, i also tried fitting the other upper into the incriminated lower and im getting the issue again, so there is something wrong with the lower 120%

(other upper in the good lower works as it should)

the pins definitely require some pressure to be closed (not a big deal in my opinion, on my ar15s i have enlarged pins that require literally a little hammering to get them closed & open, they all works perfect)

pins goes through the respective holes............. THE ONLY difference, would be on this build im using DPMS 308 pivot & takedown pin, while there should be 100% compatibility, it could be the problem..... i have to say that the fitting is definitely not snug and

there is quite a good amount of wobble to leave space for some "tolerance" so wtf??????????????????

if it wasnt hard as hell to install/uininstall the front pivot i would try swapping the pins from the other one and test them.

i want to repeat that testing this build with the pivot pin disengaged will make it work, as soon as i lock it in place the issue pops up.

[hk_shootr]

Can you insert the magazine with the upper & lower pinned and BCG installed with bolt in battery?
Sounds like the upper receiver is mot properly machined and the magazine is binding when it enters into the upper receiver.

[Lallop]

i can, but takes ALOT of force to insert it.

i want to "discard" this option, because i get the same issue swapping the upper with another one. so i recon the problem must be with the lower.

[SomeOtherGuy]

Im using 25 rounds p mag, i have another AERO 308 build and they fit great and drop free when releasing the mag catch.
i have tried with the lower alone (no upper inserted) and the mags fit as they should & drop free, i also tried fitting the other upper into the incriminated lower and im getting the issue again, so there is something wrong with the lower 120%
***
i want to repeat that testing this build with the pivot pin disengaged will make it work, as soon as i lock it in place the issue pops up.

Yeah, it sounds like the new lower is out of dimension somewhere, like in the location of the pivot pin hole or the height of its upper surface. Either way, I think your best next step is to call the manufacturer and explain the problem. FYI they will probably want to see photos too before issuing a call tag or RMA, whatever they might do. But it sounds like a machining issue.

[Lallop]

thats what i tought too, i will try swapping the pivot pin and install the aero one, just to double check....

these things really ruins your day, youre happy to put togheter the new build and a sad trombone just start playing lol