I know the Captured detent for the rear take down pin has been posted before, and there was some mentioning of a captured detent on the Safety Selector or buffer tube. I couldn't find a post about it, so I figured I would make my own.

My modification replaces the regular detent with a 1/8" hard chrome ball bearing.


Tools Required: Flat Head screwdriver, 8-32 Tap and Tap Handle, 5/64 allen wrench, a 1/8" drill bit, and a set of diagonal cutting pliers (dikes).
Materials required: 1/8" ball bearing, 8-32 x 3/16" set screw, cutting oil.

So here it goes.

First things first, remove the pistol grip, detent spring, and detent. Then remove the safety selector. Use the 8-32 tap and tap out the hole from the bottom. Go slow and use some form of cutting oil.


Then put the 1/8" drill bit in the tap handle and use it to clean out the hole all the way into the area where the selector passes through. This ensures that all the rough edges left from the tap are gone as well as smoothing out the hole for the ball bearing.


Insert the selector lever, then insert the ball bearing. Using the detent spring, ensure that the bearing is making contact with the selector surface. If not, try cleaning the hole with the drill bit again.

Now it's time to trim the detent spring. I start off at 3/8".


Insert the spring and set screw. Test the tension on the selector lever. It's probably too tight at this point, so remove the spring and trim it a little bit more. Go 1 coil at a time to avoid taking off too much. I usually end up with a section that's a tad longer than 1/4".

Once youve got the tension where you want it, put a small drop of oil in the tip of the spring, reinstall the spring and set screw.


Most of you are probably thinking this is a waste of time, and for most people it probably is. What I do know is that on the two lowers I have done this to, they show substantially less wear on the selector lever than the two other lowers that I haven't done yet. My theory is that down the road I will have to replace the detent/selector less often. As always YMMV.

That one is not nearly as much of a pain in the ass as the rear takedown pin detent spring.

Good writeup.

Thats interesting, I bet that smooths out seletor switching

Good write-up, interesting idea.

Where can I get one 1/8" ball bearing?

I actually had to order 100 of them from Fastenal as none of the local hardware stores stocked them. If I could only find the proper springs cheap, I'd do some kits up for sale so people don't have to mod their own springs.

You could just cut the detent in half, and then round off the tip a bit.





ETA: but it's definitely a good writeup on a useful mod (especially if you change grips a lot).



 

good write up and a useful mod
I havent done either mod yet but next time I play hooky from work I might do all my lowers

Note...one doesn't tap all the way through, just enough to capture the set screw.

If you replace the detent with a ball bearing, can the selector be forced out of position if it's pushed hard from the right side?

IOW, will the ball bearing keep the selector in alignment the way the pointy-ended detent will?



And if you run the drill all the way through, there's nothing to keep the ball bearing in place if the selector does get pushed out of place.



WRT the ball bearing, is this the same as the one used in the A2 rear sight?



Still, this is another good idea worth consideration.



Now, if someone would just come up with an elegant way to pin that damn buffer detent in place!

That's a good idea...would it help/be necessary to add a drop of Loctite 222 to the set screw?

set screw cant back out since the grip is going to butt against it.


cool mod, definitely usefull if you like to play dress up with your ar's.

sure it can, in theory, because there is a hole in the grip where the spring used to fit in before it was trimmed to depth for the set screw.

Cool idea, however if you do like many of us and just rotate the safety 45* and push it out in order to fiddle with trigger bits the ball will go shooting out the top. The factory part stays in place ready to be pushed back down.

Thats exactly what I was going to post, however, I have never been able to remove the safety like this. You should be able to remove standard lower parts with the safety still in.

In theory?

Do the math,  a  .1640" screw is going to back out into a .1200" hole in the grip?