What is this AR part called?

[willki]

I bought an AR many years ago built for accuracy by a great gunsmith.  Sadly I sold it.  But I remember that it had inset screws instead of trigger pins.  These screws had sleeves with an angle cut into each side such that when you tightened the pins the two sides pushed against each other to expand the diameter a bit and make sure that the trigger was super tight in the frame with no play whatsoever. 

I can't seem to find screws like that anymore and I would like to get some if I can find them.

[Omega]

Anti-rotation pins?

Anti-walk pins

Edited November 28, 2023 by Omega
add pics

[willki]

6 minutes ago, Omega said:

Anti-rotation pins?

Anti-walk pins

Not exactly like either one of those.  These were cut apart in the center at an angle so that when they were screwed back together they expanded as much as possible making the fit super tight.  Another feature is that the screws were recessed a bit so that the screw heads were pretty flush and didn't stick out beyond the frame much if any at all.

 

[Omega]

13 minutes ago, willki said:

Not exactly like either one of those.  These were cut apart in the center at an angle so that when they were screwed back together they expanded as much as possible making the fit super tight.  Another feature is that the screws were recessed a bit so that the screw heads were pretty flush and didn't stick out beyond the frame much if any at all.

 

May have been a custom lower and anti-walk pins, most lowers do not have any recesses due to how the standard pins sit flush with sides. 

This one is molded plastic with built in recesses for the bugle-head screws.

[Capbyrd]

It sounds like some version of anti-rotation pins.   An unnecessary accessory on an AR.   Trigger pins are meant to rotate.  So long as you take care of your rifle and inspect parts when cleaning, you won't run into problems. 

 

The reason that these are even a thing is poor QC from a number of manufacturers causing out of spec receivers and parts. 

[krunchnik]

If the pins were tight into the trigger group the movement of the pins in the lower receiver would wallow out the holes-

Primarily wrecking the lower-

[Johnny Rotten]

7 hours ago, Capbyrd said:

It sounds like some version of anti-rotation pins.   An unnecessary accessory on an AR.   Trigger pins are meant to rotate.  So long as you take care of your rifle and inspect parts when cleaning, you won't run into problems. 

 

The reason that these are even a thing is poor QC from a number of manufacturers causing out of spec receivers and parts. 

 

1 hour ago, krunchnik said:

If the pins were tight into the trigger group the movement of the pins in the lower receiver would wallow out the holes-

Primarily wrecking the lower-

Cheap insurance on a FA lower and a must if you were shooting 9mm in FA, 9mm will wallow out your trigger pins holes.

Edited December 23, 2023 by Johnny Rotten

[Erich]

I am wondering if you had standard anti-walk pins, but possibly the take down pin was the item that had the wedge screw arrangement? JP use to make one a while back.

Trigger pins diameter are small enough that the wall diameter combined with the smaller screw, I'd think it wouldn't generate much torque on a limited engagement area to be effective long term.

[willki]

58 minutes ago, Erich said:

I am wondering if you had standard anti-walk pins, but possibly the take down pin was the item that had the wedge screw arrangement? JP use to make one a while back.

Trigger pins diameter are small enough that the wall diameter combined with the smaller screw, I'd think it wouldn't generate much torque on a limited engagement area to be effective long term.

Yes, you are correct.  The pic is like what I remember.   They might have been take down pins instead of trigger pins.