New Colt LE6920 - "Non-Typical" Castle Nut

[arptsprt]

Picked up a NIB Colt LE6920 from a LGS yesterday. I was the first one to touch it out of the factory box and the counter guy even had me cut the "Tamper" tape on the box...

Overall, everything checked out good upon inspection. Nice carbine. One observation was the castle nut is not like any other I have seen? No notches on the exterior edge. Only two holes 180 degrees opposite each other. I really don't care as it's properly staked and I don't intend on removing it but any insight from experts like IG or markm? I'm just curious. Search came up with nothing.

[dentron]

Google "old style castle nut"
http://www.brownells.com/gunsmith-to...prod21254.aspx
https://www.m4carbine.net/showthread...ol-for-the-job
That should point you in the right direction.
ETA:
Its just an older style nut. If you aren't planning on removing the reciever extension I wouldn't worry about it. And if you so take it off just replace it with the new style.

[arptsprt]

Thanks. I had no idea there was a new style and old style...

Interesting. The "born on date" from the Colt factory says the gun was built in September 2014. Wonder why Colt is using an old style nut on a current production gun? This is a MagPul version. Wonder if that matters?

[JoshNC]

Pretty common for Colt to use parts on hand to build rifles. This is why there are transferable M16s with a1 spec receivers that are marked M16A2 with all proper M16A2 roll marks, upper, fire control group, etc. They likely found a bunch of old style castle nuts and used them to assemble rifles.

[Iraqgunz]

Interesting because I have an old Colt locking nut and it didn't have the provisions for staking nuts. I also find it hard to believe that these were just laying around somewhere.

[SoDak]

I think Colt Canada produces a castle nut like that. Is it possible Colt got some parts from them?

[markm]

I've observed over the years that the one consistent thing about Colt is that they're NEVER consistent.

[dentron]

I found some pictures of both styles. Interestingly some referenced a bushmaster part number 5310-917-1153.

[JasonB1]

What's type of rear sight is that and is it original? Looks like a detachable carry handle or Mk18 type variant.

[arptsprt]

Good eye. It is a detachable Colt carry handle I put on there. It is a take off from my "Restricted Gov and Mil" Colt LE6920 I bought several years ago that has an optic on it. I am going to leave this new LE6920 as a bare bones iron sight carbine...

What's type of rear sight is that and is it original? Looks like a detachable carry handle or Mk18 type variant.