Modifications to an M16 Lower

[Beretta686]

Now that my M16 is going to finally be in my hands soon, I'm wondering if there's any mods I should do to make it last longer, as I plan on blasting the hell out of it.

I've seen all kinds of things like KNS pins and such but I'm not sure if they're a gimmick or not.

Is there anything worthwhile doing to an M16?

[Willie Lowman]

I don't know but I have been told, the KNS pins do help. Especially if you run a 9mm conversion on your M16.

[Machineguntony]

I don't know about modifying the lower, but I think it is important to shoot a different upper, instead of the original M16 upper.

I intend to use my M16 lower with a Colt LE 10.5 inch upper.

A complete M16, with original upper and lower is worth about $5,000-8,000 more than an M16 with a non A1 or A2 upper. Do the search on gunbroker, and you will see a huge difference in pricing.

I am going to set aside the original upper and just keep it as a collectible.

Also, here is what a dealer told me. If you decide to mess with the lower, be very careful you do not lose the sear. He says that the most common way that sears are destroyed is that they are lost. You're out in the woods, or some other setting, you open the gun, and the sear falls out due to some faulty reassembly, etc, and your sear is gone, and then, for whatever reason, you can't find it or don't know that it's gone. He says that he fields calls from people who lose their sears. I have a registered receiver M16, so I do not know if on a RR M16, the sear can be replaced.

With the M60, a known problem is the trigger group falling out, and the shooter not realizing that the trigger group is gone, and then losing the trigger group (apparently the trigger group is held by a easily worn retainer part). On an M60, since the trigger group isn't the registered part, you can just buy a bunch more sears and trigger groups (that's why I already have six sears, which are only like $25-50 each). On an M16, if you lose the sear, you are out $20-30,000. Scary thought.

I have no personal experience or knowledge on this issue. It is just info that is passed from an NFA dealer to me. Take it for whatever it is worth.

[Nickel Plated]

If you bought a registered lower, then the lower is the machinegun, not the sear. The sear is just a part like any other part. If you lose your sear, go to Brownell's and buy another one, they sell them for like $15.
http://www.brownells.com/rifle-parts...prod41732.aspx

Back Ordered for now. But I'm sure they're not hard to come by otherwise.

Either way the auto-sear in itself is not illegal. Now if you do not have a registered lower that that sear could arguably be used as a legitimate part for but you have some semi-only lowers. Then you could possibly, maybe, theoretically get snagged up on some constructive possession charges.

[Beretta686]

I don't know but I have been told, the KNS pins do help. Especially if you run a 9mm conversion on your M16.

I've heard that too, as there's something with the way it can wear on the receiver's pins. But I've never seen anyone actually show that it's helps out.

I have a registered receiver M16, so I do not know if on a RR M16, the sear can be replaced.

I think you're confusing a Registered Receiver with a Lightning Link or other auto-sear.

If you're getting a Registered Receiver, it's no different than any other AR type platform where the stripped lower is the weapon and parts are just parts. While an auto-sear (legally speaking) is the weapon.

[Ricklin]

The sear does not just "fall out" of an M16. It sounds to me according to the warning provided by your dealer that you bought a lower with an installed lightning link.
I recall M-16's from my time in the military, the sear can not fall out. That would be a bad deal for a military weapon. The sear is a major part of the trigger assembly on virtually every gun, full, semi, etc. No sear means the gun does not function at all.

Sounds like what you bought is a gun with a Lightning link. If that is the case and the gun was represented to be a registered lower, I would be looking to get my money back.

[Skans]

Sounds like what you bought is a gun with a Lightning link. If that is the case and the gun was represented to be a registered lower, I would be looking to get my money back.

I'm wondering if it was possible to "marry" a lightning link to a lower and then register the lower+lightning link as one unit? If this is possible, then I'd think (and I have no way of knowing if I'm right on this) that the owner of the registered lower could simply destroy the lightning link and then modify the lower to accept an M16 full-auto sear. It would really just be a repair to an already registered lower receiver; of course the serial number of the form better be on the receiver and not just the lightning link.

[Sharkbite]

Sounds like what you bought is a gun with a Lightning link. If that is the case and the gun was represented to be a registered lower, I would be looking to get my money back.

^^^^ THIS^^^^^

A lightning link WILL just fall out if the gun is opened. Nothing holds that in except the upper and lower being closed. A regestered rcvr will have the trigger group (incld the auto sear) held in by the trigger pins. Nothing can just fall out (as long as the pins are in place)

If you paid for a REGISTERED LOWER and are getting just a lightning link. Youve been HAD. I dont know the dollar figure difference but its in the THOUSANDS.

If this was me... Id walk into my dealer and ask to see the gun. If a little piece of metal is just hooked over the disconnector.... Ohh boy!!!!

[Willie Lowman]

A regestered rcvr will have the trigger group (incld the auto sear) held in by the trigger pins. Nothing can just fall out (as long as the pins are in place)

Wrong


There are many Registered Receiver "M16" rifles out there that are SP1 or AR-15A2 that have a DIAS "married" to them.


for visual identification.
M16 auto sear

DIAS

[Sharkbite]

Does a "registered receiver" use a DIAS??

I thought DIAS were the registered part. Just like a lightning link

[Willie Lowman]

If a person bought one of the pre-81 DIAS and put it into a AR-15 that would make the AR a machine gun. If a person filed a form 1, registering the AR-15 as a machine gun, they could put that auto sear into it legally. The auto sear is a conversion part and is now a permanent part of the gun.

I thought DIAS were the registered part

That would be referred to as a RDIAS.

There are a lot of married DIAS Registered Receiver guns out there. Lots of AR-15s were converted this way. Many Uzi receivers were registered and converted with slotted bolts. In retrospect, it was not the best way to do things but back then it was the easy way.

[Machineguntony]

I am not a machine gun expert, so I just rely on the dealer who is holding my gun to examine the gun for me. He says it is a registered receiver M16, and a very good M16A1 and A2. I bought the guns from a very well known and reputable dealer.

From my understanding (again, I am not an expert and don't even have a MG in my possession yet), the sear can fall out if it is DIAS. That's what I have been told. I have no idea what is a lightening link.

That's just what I was told.

[Willie Lowman]

http://www.quarterbore.com/nfa/lightninglink.html

This is what a Lightning Link is. It's two bits of sheet metal that make a AR-15 full auto.

[Skans]

Willie, if someone has a registered receiver that is married to a lightning link; is it possible to fix the lightning link, if it breaks by installing an M16 sear and destroying the LL? I know this sounds logical since the receiver is already registered, but I also know that there is no logic with he NFA or BATFE.

[Willie Lowman]

the LL or DIAS can be repaired but not replaced. A registered receiver that was converted to full auto using these kind of parts cannot be changed to operate in a diffrent way. ie Destroying a married DIAS and drilling a hole for a sear pin.

[Skans]

Thanks Willie, that's what I thought, but I wasn't sure about it.