Do any members know which mfg's drill their 80% lowers with the proper hole for the safety detent ??? I am working on my first AR build and found when I installed the safety detent it did not enter into the detent hole far enough to engage the safety. After some research I found this is apparently often the case with some lowers. I haven't heard any explanation for why this is the case but I assume there is some reason it is not done in some cases.

I drilled mine out and it seems to be functioning correctly but I am not a gunsmith/machinist or a skilled fabricator and don't like trusting my work on something as important as the safety. I also found the holes on the side plates where undersize and I had to drill them out as well.

Thanks for any input....

My Hell Fire Armory was all the way through I guess. I didn't have to drill any more than the 3 holes...I don't think.
It was a few years ago but I am certain I didn't have any other drilling.
https://www.hellfirearmory.com/ar15-lower

Right To Bear, Matrix, Ghost Firearms/Grid Defense all had the safety detent hole drilled properly in my experience.

What lower did you use?  I was under the impression that they were all drilled.  Add that to the other problems you had makes me question things.  What jig did you use?  Did you de-burr the holes after drilling?

To answer 42junkpile.....I live in the Republic of Kalifornia so I want to be careful what I write in public. This state may pass a law (retroactive) that might allow them to roll out and take my AR.

That being said I will say the lower was a gift to me. I don't "remember" the manufacturer and don't "remember" the jig I used to complete the lower. As I noted above after some internet research I found many people discussing how this selector detent has a small shoulder on the upper end (the end the spring touches). The detent resembles a bullet, the end that engages the selector pin is pointed and the upper end (that the spring is pushed down against) has the slightly larger necked section.

A hole is drilled through the lower that will allow the lower part of the detent to pass through and engage the selector/safety pin. But that hole needs to be small enough to not allow the  necked portion of the detent to pass through and drop out of the lower. So if you think about it, when you drop that detent into the hole in the lower the reason it doesn't just fall out the lower end of the hole is because the hole is necked down at some point. Hole starts at the top one size and finishes with a smaller diameter at the bottom. Makes a shoulder.

On my lower when I dropped the detent in it only went to the point it was sitting flush with the top of the hole and I could see the lower point of the detent just barely starting to show up in the pin hole. Wasn't entering enough to engage the selector pin or allow the spring on the other end to be captured in the hole. There was a small hole all the way through but to small for that lower section of the detent. Almost like it was a pilot hole or built for some other type of detent.

I just drilled this lower section of the hole out to accommodate  the lower section of the detent. Seems to be working alright but I would not want to do this again if I could help it. It's to involved for an amateur like me especially having to do with the safety.

Anyway if I ever buy another 80%'er I'll try to confirm with the maker how this part of the lower is set up.

I was searching the internet again and found quite a few blogs of people dealing with this. Several of the post were from this forum. A member on this forum named PookiesCuppycake gives a very good explanation of the whole issue and how to deal with it.

I must not be using the search on this site correctly as I tried several searches here on the subject but found no results. But searching the internet I find a number discussions on this site about this subject. Go figure...….

I have a few on the shelf, so I checked them. All way past the required depth for this job.

If it works, I wouldn’t give it any more thought.

More than likely, when you bored the hole for the safety lever, you raised a burr in the detent hole.  Happens all the time.

Thunderguns lowers are drilled.
Havent had a bad one yet.