1. Is there any reason why a RLL would not work with an AX556 lower?

2.  Is the Geissele SSF compatible with a RLL?

3. What components are needed to make a RLL select fire vs. full auto only?

I’m trying to educate myself on options, I’m also considering a lower end RR, no way I’m paying 30K plus for a RR or RDIAS.  I’d also prefer to use the AX556 lower, I’d have 1 dedicated lower for the RLL.  I’ve become very spoiled with this lower.  Thank you in advance.

The LL needs a low shelf lower.

I am sorry, I don't know the finer points of that trigger.

There are a couple of different ways to get select fire.  I would suggest  going to  http://www.quarterbore.com/nfa/lightninglink.html for basic information.

Scott

if you are looking to get into the transferable M16s market as cheaply as possible your options are a RLL or a non-colt RR.

The RLL is nice because it is the cheapest and you can use modern lowers, but you are limited you on trigger options, cant run 22lr and must use a SP1 BCG. You can still use a Shrike with it but you will have to have someone mill the BCG to the right dimensions of a SP1 carrier.

I personally recommend the non-colt M16 RR. It will cost you a few thousand more, and may need a trip to a gunsmith to work out some of the spec issues but once done it is plug and play like a colt lower but for a fraction of the cost. You can use geissele triggers and there is a much larger selection of M16 BCGs out there. You also don't have to deal with broken or bent paddles, timing issues, etc..

In regards to broken/bent paddles, doesn’t the KNS protector make that a non issue?  That issue aside, it seems that with the RLL trigger options are limited,  but I can use a beloved AX556 lower.  With a RR I can use whatever trigger, but bye bye ambi controls.  I refuse to pay the shot for a colt M16 RR or a RDIAS, I’m priced out of that market st this point.

I know the KNS protects the RLL, im not sure if it protects the paddles, I was always under the impression they were a wear item.

If you really want a AX556 lower for ambi controls then def go with the RLL. You are stuck with a single stage mil-spec trigger but if that isn't that big of a deal no worries.

The only way you get both features is a RDIAS, but youre looking at $35k for one vs $15k for a RLL.

Honestly if the gun is set up and timed properly there is really no need to replace the paddles.

I bought my first of two Lightning Links in 2004 and its seen more rounds than I could even imagine to count and its still using the original paddle.   The same goes for the second one bought in 2011.

I do have a whole pile of spare paddles of varying thicknesses I bought a decade+ ago with the first RLL that I have never touched.

I concur.  I assumed they were a consumable going into RLL ownership, but it is shocking how they hold up.  I've not seen the peening of the upper rear lug yet...apparently I need to shoot more!

Regarding lowers, you can make ANY lower work with the RLL, it just depends on if you want to machine the required clearances or not. On this topic, I am a fan of clearancing out the rear FCG pocket as well (deeper than spec.). While I have never personally seen a broken RLL, I suspect that some (maybe most, if not all) of broken RLL ears were actually a result of the link slamming into the FCG rear wall and NOT getting 'torn off' by the force of pulling on the disconnector. The KNS-style of protector provides the required protection for this type of damage as well.  You should always run with some type of protector design on your RLL.

v/r,
Esox

Why would the relationship between the carrier and rear lug change just because you change uppers/carriers if everything is set up identical?

The rear lug is always in the same spot as the rear takedown pin is in a fixed spot in the lower and if you cut all your carriers to be identical than the gap is always the same as well.

Now if you buy a bunch of carriers from different vendors and hope they will all be the same SP1 "spec" ....than sure, you will need to change paddles out to compensate for the myriad of different carrier ass end dimensions out there.

If you then don't change the paddle to compensate for the different carrier to rear lug gap dimension than you will also bend and or peen the upper portion of the paddle over time.

However, if you cut the carriers yourself, than you can make them all identical, which means identical gaps, and no need to change paddles.  If the link is also set so that the trip point of the disco is when the link is close to vertical and flat against the back of the rear lug and not having to get significantly  pinched between the upper portion of the rear lug and the carrier, than you will have virtually no peening on the upper convex section of the rear lug or the paddle itself to contend with either.

The only upper I have ever come across where the rear lug was significantly out of dimension (under sized front to back) was my FM9 lower and which was easily remedied via a small shim attached to the back of the lower to bring it up to spec.

In terms of hammer drop timing (carrier to barrel extension gap) I have never really seen any significant ROF difference for a couple hundredths or thousands of an inch different in terms of when the hammer falls.   The main reason for controlling timing of bolt gap when the hammer falls isnt for ROF adjustment, its for controlling cartridge ignition. More specifically it's so that the hammer doesn't fall too early and hit the carrier before it is fully closed or too late when the carrier is potentially bolt-bounced open.  In both instances if the hammer contacts the back of the carrier when it is slightly open and away from the barrel extension, than you don't get as good a strike on the firing pin and/or the firing pin cannot get as good a strike on the primer.

I am not sure about the FBI muzzle break, but with practice an M16 is extremely controllable without the need for any type of muzzle break in my estimation as the platform doesn't really produce much recoil or muzzle rise. What little bit of recoil it does have is pretty much straight back into your shoulder given the linear recoil arrangement.

While lighting links have a distinct advantage over DIASs in terms of "plug and play" on semi-host guns that have been set up properly....I don't ever  move a link into a host (lower or upper) of unknown dimension that I have not personally set up, as that is a good way (in my opinion) to potentially damage your RLL.

While RLLs are certainly more fragile than say a steel DIAS, I think they honestly get a bad rap for breakage not because the design is substandard per say, but they get put into host guns that are not properly set up to run them.  As ESOX mentioned you can damage the link ears by over-pivoting the link and allowing it to ram into the back of the rear lug pocket, the low shelf isn't as low or the lug is thicker than expected causing binding of the link between the upper and lower, somebody has an overly strong disco spring or an oddly shaped disconnector, the semi hammer is not properly relieved so it hits the link when being cocked back, their carrier isn't cut properly, or just running them with unknown uppers that have overly high ROFs, etc.

The story above about the guy who is getting a good deal on a link because the current owner couldnt get it to work is almost identical on how I got my first link.  Similar arrangement where the former owner bought the link, a bushmaster "low shelf" host gun, even sent it to the Lighting Link "Guru" of the day (Scott Bell) and still could never get it to reliably function.

When I took the whole deal apart it was just a complete pile of WTF.  The link appeared to be rubbing between the upper rear lug and lower shelf, there were obvious marks in the lower where the link was hitting the side walls of the lower receiver where it narrowed toward the rear lug pocket, the burst kit arrangement was a hack job at best, and to boot he was using one of those mid 90s/early 2000s era "semi" carriers with the curved radius on the back end.  The paddle was all chewed up as was the upper from the paddle being mashed between the carrier and rear lug.  Even the "Auto" engraving Scott Bell did on the lower was pretty crappy.  I have no doubt that if he had continued to try and run that setup that he would have killed that link.

Maybe I am overly protective, but my Links never leave my properly set up host guns and I spend a good amount of effort making everything is 100% correct.  I even have a upper receiver that I have cut up so that I can see the link actuate within the lower while hand cycling to make sure there is no binding whenever prepping a new lower and to make sure the timing is good.

How often (how many rounds) do you find it necessary to change paddles in your properly set up host gun?

If everything is set up correct, you would never need to replace a paddle. Now that I have settled on one configuration that is set up correct as far as lug and carrier, I do not notice any wear on the paddle.
All it does is lever the link to pull the disconnected. Not much resistance, again, if set up right.

How would you go about measuring/checking hammer release timing?  Just holding down the trigger in auto and racking the rifle?  What would you be listening for?

Have you you not experienced any peening of the rear lug that Dano mentioned?

Thank you

Virtually never.   I have made some changes over the years as I experimented with my own custom link protectors,  but I don't recall ever replacing a paddle because one "wore out".

I have not changed a paddle out for any reason in the past 7 or 8 years.

I notice a little bit of anodizing missing are the curved section of the rear lug as pointed out below, but its just cosmetic.

Attached File


If the link is set up the way I like, the disco should pull back when the link is almost vertical and it does require the link to be pulled back past the vertical point.

1. At rest the link has no tension and is loosely held between the carrier and rear lug in a vertical position.

2. You pull the trigger which releases the hammer and cocks the link in a forward position in relationship to the rear lug.

3. The hammer releases and the round goes off.

4. The carrier come back and the link is now pulled forward against the rear lug.

5. The carrier come forward hits the paddle and trips the disco when the paddle is back vertical.

There is no need for the paddle to be cammed backwards farther than the vertical position.  This is what causes peening on the paddle and also slams the link into the back of the rear pocket unnecessarily.

I suspect when guns are not set up correctly folks use extra thin paddles to try and minimize the peening/pinching.  This just exacerbates the issue as the paddle is extra thin and still gets pinched.

Use a thicker paddle, properly timed so that it drops the hammer when in a vertical position, and you wont peen the upper or chew up the tip of the paddle either.

Excuse my basic MS Paint Collage.

Attached File

I’m blown away by the responses and knowledge provided in this thread, thank you to all who have contributed.  I was leaning towards a RR, but I think it might be worth it to hold out for a RLL (assuming one pops up for sale, they seem to be unicorns).

Out of curiosity, did you buy the cut out upper or make it yourself?

I actually have two and made them both myself.  One that is just the back portion of an upper, so its the rear lug and rear charging handle area and another upper that has "ports" cut into it.

The rear only portion cut upper has better visibility, especially around the fire control group but wiggles around a bit more on the rear takedown pin without the full structure (both front and rear pin holes).  You can't use it with a carrier in a full function check since 90% of the upper was removed.  The one with port holes is "functional" with a carrier but doesn't provide as much visibility.  

Stripped uppers are pretty cheap, so if you own a $15,000 RLL its pretty cheap insurance to pick up ~$50 stripped upper and take a dremel to it so you can see if you link is functioning properly and not binding up.

Can you give me more information on how these drill bits are used? I get what a go and no-go gauge is but what is this telling me?

This is great information, thank you very much (to all the rki’s In this thread).

@Esox

He helped me quite a bit.

Not to rehash information posted.

1.  Expect to mill out a lower, even if it’s low shelf.   So that end, pick any lower you like.  It doesn’t matter.  
2.  Forget about speciality triggers.   Modify a real Colt burst trigger.   You are already putting in a LL into a system that wasn’t designed that way, why add more variables to make it not work?  If I’m shooting for groups, I’m not using the LL (so the trigger isn’t that big of a deal).  
3.  I have many paddles but I’m still on my originals.

Get a 9mm, it’s great in 9mm.

Silly question, does anyone make an ambi safety for the M16a2 burst FCG?

KAC or Colts ambi selector for the M4A1s should work.

Bad-ass full auto safety lever works as well, and has a positive stop so it doesn't rotates 360 degrees on lowers that do not have selector stops. I've used two of them in my rll lowers with modified burst kit.

I just impulse bought an RLL...looks like I have some research to do

Thank you sir, I’ve become spoiled with ambi safeties.  I run the talon 45 degree throw on all my rifles, so this would still take some getting used to.

Congratulations on your purchase, just search out rll and look for jbntex posts, and you'll know everything you need. They aren't hard to get running. First step though is get a kns protector on there and don't just drop it in unknown lowers.

young mfg makes an rll carrier, might check those out, but they only seem to do batches. Keep an eye out for 3rd burst trigger kits in ee for a good price to convert to select fire kits. If you have a dremel with a cutoff wheel and 5 minutes you an do the conversion yourself.

Thanks!

I have a Noveske Chainsaw lower for my SBR that I'm planning to "tune" it with and keep it in. I have an SOT friend who has one and can do the tuning for me - I'd never trust myself lol worth the cost.

For sure getting the KNS protector shortly. I have burst kit that came with my other M16 (SP1) that I've never touched - I'm sure I'll look into it though.

Lookin forward to educating myself on all of this while I wait

Congrats! As others have said, it's not hard to get running. I did it myself when I impulse bought one about a year ago. I've had it out a few times and it runs like a sewing machine. Do your research and ask questions...lots of knowledgeable people here. Buy a KNS protector while you wait, if it didn't come with one.

In my opinion, they are way underrated and pretty versatile. Enjoy!

Threads like these are making me think about picking up a lightning link instead of a RDIAS. Then I could spend money on something else.

Thank you! Yes, very underrated and wanted to get ahead of the curve. I'll buy a KNS protector soon. I'll need a bolt too as mentioned above the Youngs people might be able to provide. I'll at least be able to spread this stuff out over the stamp wait time haha.

You could buy a RLL and another subgun or two for the price of an RDIAS. Something to consider...

you could buy two lightning links for the cost of a rdias.
Or hell, get a lightning link and a beater m16 off brand for the cost of an rdias. I'd go that route.

Has anyone milled out an adjustable gas bcg like the silencerco or bootleg bcg? I want to reduce the gas and pounding of a can while still rocking full auto. Anyone know if they still work?

Is Quarterbore still around? I don't think the website has been updated in years. Just curious as he seems to know his shit about RLLs

I have a few questions on the lightning link and I think this is a good thread on them.

I know you can’t use a Geissele SSF trigger with a lightning link, but how does the modified burst trigger feel compared to the Geissele SSF?

Can you use the rLL on the FM 9 beltfed or CMMG guard? I know you would have to modify the bolt carrier, but I haven’t heard if you can make it work on these rifles.

With the KNS protector and correctly modified lower there shouldn’t be any problems with the rLL breaking. In theory the rLL should last a very long time, correct? I would like to pass all my NFA stuff to my son way down the road.

I’m am primarily going to shoot rifle calibers with the rLL if I get one , but it would be nice if those pistol caliber uppers worked. I think it will be a cheap alternative to a rDIAS and I could put the extra money to something else.

Anyone mess with 762 with an RLL? I’ve seen some videos that look successful

Thanks!

Glad to hear about the burst kit as well. I have one already (looking for a good price on a 2nd atm). Going to have 2 lowers milled and tuned for it.

Just found this from a reddit user (could be one of you guys?). Great video, I haven't finished it yet but very informative so far. RLL overview

https://www.youtube.com/watch?v=732Zwy7egu0

I mean, it clearly says it’s Esox.

He’s helped me out with my rLL.

Edit.  I even posted his name in this thread on 5/3/18.

word