[ARCHIVED THREAD] - Front Sight Detent Diameter

Posted: 9/20/2014 12:14:12 PM EDT

Folks,

I have a front sight detent that measures .168 diameter. The milled hole is considerably less than that. Are there more than one size diameter of front sight detents??
The front sight tower is a a DPMS. I removed it to put on a block for a scoped flat top upper. Do I just find an appropriate size drill and open it up??
Thanks !!

Ripsaw

Posted: 9/20/2014 5:19:16 PM EDT

[#1]

The hole for the detent is supposed to be .171 + .003. I imagine your detent should fit if the hole is the correct size. How was it assembled if it doesn't fit now? I don't have a mic in the house to measure one.

Posted: 9/21/2014 8:45:29 AM EDT

[#2]

It would make sense on a mil-spec sight tower to have the the proper detent hole. I have found no evidence of more than one size detent pin. DPMS just shows one.
I'll fire off an e-mail to DPMS and have them explain.

Ripsaw

Posted: 9/21/2014 9:42:49 AM EDT

[#3]

A M16 / M16A1 blueprint drawing lists the diameter of the hole for the front sight post detent as measuring 0.171" + 0.003", and has a depth of 0.738" +/- 0.010".

Posted: 9/21/2014 2:17:52 PM EDT

[#4]

I ran a 4 mm cylinder burr down the hole. A large metal burr/flashing wrapped itself around the bit.

The blockage was flashing with dark oxide fusing it in place.
Works fine now. I touched up the surface with Ox-Pho blue, spritz it with brake cleaner, put a drop of lube on it, and assembled it.
Finished.

Thanks for the help gents!!

[ARCHIVED THREAD] - Front Sight Detent Diameter

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[ARCHIVED THREAD] - Front Sight Detent Diameter

[ARCHIVED THREAD] - Front Sight Detent Diameter