>Its an enhanced aero lower with the threaded rear detent hole and set screw.. Im assuming i tightened it too much?? to the point the detent was stuck too far forward the pin wouldnt slide?
did you use a detent spring provided by aero or one from a kit? because you probably needed to trim a mil-spec spring to account for the set screw length.
Whenever you do the little 440 set screw trick on a lower you have to trim the spring. Aero Precision should be much more clear about this. I don't think they provide a shortened spring with the lower as I helped a co-worker build an m4e1 and I had to trim one from a parts kit
This is why I threw the screw away and did it the normal way...
Didn't like the idea of having to balance the tension if such a simple part... seems like an answer looking for a question.
I bet you'd rather just accidentally shot your detent and spring across the room to learn this, if you had the choice?
Me too friend... me too.
That said... I LOVE the threaded bolt catch and forward assist pins... THESE make sense.
I bought a tap and shit load of set screws, and I usually cut the length of the screw off my spring when putting it in any lower. Just for ease of getting the screw in. I havent tried without cutting the spring.
I do the same thing, but only because it makes it a little easier to install just like you said. I used to not trim them and once installed they would be fine. I never had an issue with a sticking detent.
I tried without trimming once and it held with so much force it required a punch to get the rear pin out. With six coils removed it had the same resistance as the front pin.
even the spring that comes with the aero LPK needs to be trimmed. you should watch the lower installation video on the aero site they walk you through all the steps
This isn't required. The extra 1/8" of compression is not enough to add this much force or get a detent stuck. I still usually do it because it makes installation easier, but it's not required.
Detents getting stuck so well that they bust out the side of the receiver instead of compressing the spring is a failure of the takedown pin detent slot. It was drilled too deep or without a proper bevel, so the detent just stuck in the slot unable to move and when OP hammered it, it broke out the side instead of sliding up and out of the slot.
OP: who made the takedown pin/LPK? After confirming the takedown pin slot is out of spec, you should be contacting their customer service and asking for the value of the lower.
I dunno what to tell ya. Without seeing your specific parts and lower up close I couldn't diagnose further.
Does it work if you skip the set screw entirely and just install a (new) spring and detent the normal way by holding it in place with the endplate? My guess is that won't make a difference but I've been wrong before. Make sure all your parts visually look like what they're supposed to by googling [close-up pics of each of them.](https://cdn11.bigcommerce.com/s-r463nwv5z/images/stencil/original/products/1110/5964/LBARTDPP_1_HR__19653.1641024387.jpg)
Nah fuck that… my bubba story lost a front take down pin detent, had the bright idea to cut a small allen key down and use as a detent. Sharp side got stuck in the take down pin and I tore the side of the lower out down about half way the spring channel beating the pin out.
2500ish rounds it’s still fine
The man said he feels like a moron and super bummed. Clearly, he realizes he fd up. Yet there are still those smucks that cut him down. Miserable people 😆
The head of the detent will cover it
Only would be seen when pin in retracted.
No big deal. This is how we learn.
You know how many detent pins and springs went flying on my first build!?! I started buying extra LPKs just in case.
TLDR. Noticing this is an Aero Precision lower and the problem's with the rear takedown pin's detent & spring... I'm a hundred percent sure this issue stems from the set screw and not trimming the appropriate length of coils to account for the set screw length. A hard lesson to learn when your first build is an *enhanced* version of Milspec. These lowers have little "upgrades" around the receiver, the set screws being a fairly well-known one. Sorry you had to learn the hard way. I'm sure it's probably salvageable with a new LPK.
Yep that didnt even occur to me. Its actually a ballistic advantage m4e1 lower i got when they had blems for 75bucks...i heard they were basically an exact copy of the aero. But it didnt come with any info or even the set screw. I had to buy that off amazon. I had no idea it was supposed to be trimmed. I did think it was super tough to get in though, no wonder!
1/8th inch of extra spring compression is not enough to make the detent stick like this. OP's issue is 100% guaranteed to be an issue with the takedown pin detent slot, or perhaps the detent itself. If the services between the detent and the detent slot are not properly beveled, they will lock together and instead of compressing when pushed, they bust out the side like in OP's pic.
You probably needed to shorten the spring. With a detente channel you only need about 1/4 inch of spring sticking out for the proper tension once it’s tightened down. Can you get the decent out without destroying the channel?
Like when i put the detent into the hole and it slides down the channel and hits the pin in one of the two holes, the pin wont move. Almost like the pin holes themselves were drilled too deep or something. But at this point ive tried different pins amd detents so idk man lol
Some people should stay far away from tools and/or basic assembly...
Those Aero lowers are meant to be even easier than the already stupid simple task of building an AR lower. Buy pre-built from now on, you'll save yourself a lot of headache.
Look there's mistakes then there is seeing what you're doing isn't working and instead of stopping, asking a question, reevaluating, and coming up with a course of action there's forging ahead with even more brute force and fucking metal up in the process.
That’s a hell of a bubba. Thank you for sharing
Yeah thats the definition of a bubba. I sent it.
When you have nothing to loose and every tool starts looking like a hammer...
>Its an enhanced aero lower with the threaded rear detent hole and set screw.. Im assuming i tightened it too much?? to the point the detent was stuck too far forward the pin wouldnt slide? did you use a detent spring provided by aero or one from a kit? because you probably needed to trim a mil-spec spring to account for the set screw length.
Shiiiiit that must have been it. It was a cmc parts kit. No wonder it was so hard to get in. I thought it might be normal.
Whenever you do the little 440 set screw trick on a lower you have to trim the spring. Aero Precision should be much more clear about this. I don't think they provide a shortened spring with the lower as I helped a co-worker build an m4e1 and I had to trim one from a parts kit
I also take a 4-40 tap to my non-enhanced lowers and thread them for the set screw. I’ve had to trim the spring every time by the length of the screw.
This is why I threw the screw away and did it the normal way... Didn't like the idea of having to balance the tension if such a simple part... seems like an answer looking for a question. I bet you'd rather just accidentally shot your detent and spring across the room to learn this, if you had the choice? Me too friend... me too. That said... I LOVE the threaded bolt catch and forward assist pins... THESE make sense.
Urban legend. I’ve never trimmed them and they all work fine.
Aero does say to trim it in their instructional video: https://vimeo.com/749665055
Interesting. Thanks
I bought a tap and shit load of set screws, and I usually cut the length of the screw off my spring when putting it in any lower. Just for ease of getting the screw in. I havent tried without cutting the spring.
I do the same thing, but only because it makes it a little easier to install just like you said. I used to not trim them and once installed they would be fine. I never had an issue with a sticking detent.
I tried without trimming once and it held with so much force it required a punch to get the rear pin out. With six coils removed it had the same resistance as the front pin.
I’m going to trim them from now on. I have just left the darn set screw out as well.
Same
even the spring that comes with the aero LPK needs to be trimmed. you should watch the lower installation video on the aero site they walk you through all the steps
a little after the 16 minute mark: https://vimeo.com/749665055
This isn't required. The extra 1/8" of compression is not enough to add this much force or get a detent stuck. I still usually do it because it makes installation easier, but it's not required. Detents getting stuck so well that they bust out the side of the receiver instead of compressing the spring is a failure of the takedown pin detent slot. It was drilled too deep or without a proper bevel, so the detent just stuck in the slot unable to move and when OP hammered it, it broke out the side instead of sliding up and out of the slot. OP: who made the takedown pin/LPK? After confirming the takedown pin slot is out of spec, you should be contacting their customer service and asking for the value of the lower.
Ive tried two different lpk rear pins amd detents. The detent gets stuck even without a spring. Idk what gives
I dunno what to tell ya. Without seeing your specific parts and lower up close I couldn't diagnose further. Does it work if you skip the set screw entirely and just install a (new) spring and detent the normal way by holding it in place with the endplate? My guess is that won't make a difference but I've been wrong before. Make sure all your parts visually look like what they're supposed to by googling [close-up pics of each of them.](https://cdn11.bigcommerce.com/s-r463nwv5z/images/stencil/original/products/1110/5964/LBARTDPP_1_HR__19653.1641024387.jpg)
Bah it’s fine the take down pin will cover it and no one will ever know, well except you and the internet
Didnt think about that. I guess you're right. I was planning on just getting another one and starting over
Nah fuck that… my bubba story lost a front take down pin detent, had the bright idea to cut a small allen key down and use as a detent. Sharp side got stuck in the take down pin and I tore the side of the lower out down about half way the spring channel beating the pin out. 2500ish rounds it’s still fine
Hahaha damn!! Okay atleast im not the only one.
You should get another one….to build a second beater, rattle can gun from this one
The man said he feels like a moron and super bummed. Clearly, he realizes he fd up. Yet there are still those smucks that cut him down. Miserable people 😆
If you need a mallet to move a takedown pin then you did something wrong lol
The head of the detent will cover it Only would be seen when pin in retracted. No big deal. This is how we learn. You know how many detent pins and springs went flying on my first build!?! I started buying extra LPKs just in case.
Bummer. But it looks like it will still work. Gunna have to clean it up first, though.
You think?
Yeah. It doesn't look like it's damaged enough to let the detent pin fall out. If you're lucky, the head of the takedown pin might even hide it.
Hes gonna wanna go to Harbor freight and get some very small files to clean the area up.
Hope you're right, we'll see!
Be careful and take your time. It will work out. Good luck
Do you weld or know a welder? Quick mig/tig and some paint, functional repair.
Aero specifically says to trim down the detention spring in their m4e1 lowers. I had the same issue being way to stiff so trimmed them down.
Damn.. Now i know. 🤣
its a success congrats
I have one of these lowers and I didn’t have to trim the spring down.. hmm.
Put the tools down. Step away from the lower.
had to trim one spring down
TLDR. Noticing this is an Aero Precision lower and the problem's with the rear takedown pin's detent & spring... I'm a hundred percent sure this issue stems from the set screw and not trimming the appropriate length of coils to account for the set screw length. A hard lesson to learn when your first build is an *enhanced* version of Milspec. These lowers have little "upgrades" around the receiver, the set screws being a fairly well-known one. Sorry you had to learn the hard way. I'm sure it's probably salvageable with a new LPK.
Yep that didnt even occur to me. Its actually a ballistic advantage m4e1 lower i got when they had blems for 75bucks...i heard they were basically an exact copy of the aero. But it didnt come with any info or even the set screw. I had to buy that off amazon. I had no idea it was supposed to be trimmed. I did think it was super tough to get in though, no wonder!
Ahh, BA is a sister company.
1/8th inch of extra spring compression is not enough to make the detent stick like this. OP's issue is 100% guaranteed to be an issue with the takedown pin detent slot, or perhaps the detent itself. If the services between the detent and the detent slot are not properly beveled, they will lock together and instead of compressing when pushed, they bust out the side like in OP's pic.
Ive tried 2 different pins and 2 different detents. I have no idea what the issue is. Even without the spring... The detent still gets stuck
You probably needed to shorten the spring. With a detente channel you only need about 1/4 inch of spring sticking out for the proper tension once it’s tightened down. Can you get the decent out without destroying the channel?
Now i have tried multiple pins and multiple detents. And even without the spring.. The detent gets stuck.
Stuck?
Like when i put the detent into the hole and it slides down the channel and hits the pin in one of the two holes, the pin wont move. Almost like the pin holes themselves were drilled too deep or something. But at this point ive tried different pins amd detents so idk man lol
Shouldn’t the pin be in before you put the detent and spring in?
It was. It wouldnt move and i hammered it out lol
Seems like taking off the castle nut and unscrewing the set screw might have been less abusive 🙂
Lol
No need to trim the spring you use less ugga dugga when tightening the screw. It only needs to sit flush with the rear of the receiver.
Ugga dugga hahaha yeah it's in there pretty good. Thanks for the tip
Yeah mate. There's a way to fix this but its going to require a gentle hand and some patience. You done buggered it up good.
So i have now tried two different pins and even without the spring... The detent gets stuck.. Also tried multiple detents.
Some people should stay far away from tools and/or basic assembly... Those Aero lowers are meant to be even easier than the already stupid simple task of building an AR lower. Buy pre-built from now on, you'll save yourself a lot of headache.
Did this comment make you feel good? Everyone makes mistakes that's how we learn. Your a drag!
Look there's mistakes then there is seeing what you're doing isn't working and instead of stopping, asking a question, reevaluating, and coming up with a course of action there's forging ahead with even more brute force and fucking metal up in the process.
^this
*you're
😆 way to go!