Quarterbore's Forums - Review of my SWD Registered Lightning Link

Quarterbore's Forums (http://www.quarterbore.net/forums/index.php)

- Machine Guns (http://www.quarterbore.net/forums/forumdisplay.php?f=39)

- - Review of my SWD Registered Lightning Link (http://www.quarterbore.net/forums/showthread.php?t=167)

Review of my SWD Registered Lightning Link

Let me start by posting a link to the Lightning Link page that has been on my site for several years now. This page is fairly complete but I have finally managed to purchase and finish the NFA Transfer process to receive my own rLL and I have been sharing the experience in other forums and I am bringing all the details here so that I can compile them and to update the LL page on the website.

Note, this thread is going to look a bit dyslexic until I can pull the various topics together...

Making a select fire kit for my Bushmaster lower...

To make a select fire kit you need the M16A2 burst kit. This sells new from Bushmaster for $60 and I used a cheaper surplus set I bought.

Here is the Bushmaster kit...
http://www.bushmaster.com/shopping/l...es/3shtbst.gif
www.bushmaster.com/shopping/lowers/3shotburstkit.asp

Now, to use the select fire kit in an AR-15 with the LL you will need to neuter the hammer. This is necessary as the rear of the hammer will hit the link and you don't really want a full auto hammer in a semi lower anyways. Here is how mine looks now...

http://quarterbore.com/images/qbi_sfkit_01.jpg

The other thing that you will need to do is remove the forward hook that interacts with the burst cam. I screwed one of my burst kits up on my first go at this as I failed to realize that you need the forward portion of the disconnect to rest on the forward portion of the trigger. Following is a pic...

http://quarterbore.com/images/qbi_sfkit_02sm.jpg
Larger pic quarterbore.com/images/qbi_sfkit_02.jpg

It is important to realize that you need the M16A2 hammer as it has a much wider area for the disconects to catch the hammer which is needed with the two disconects this system uses. Also, I elected to leave the Burst Cam attached to the hammer. Perhaps I will later remove it and replace the hammer spring with a standard M16A1 spring but it works as it is.

Now, to make the kit selctive fire you simply notch the disconector that interacts with the selector so that when the selector is placed in the semi position both disconects catch the hammer. In this position the notched disconect is not tripped by the link and I get semiauto fire. When the selector is moved to the "Auto" position, the notched disconect is pulled out of the way and the hammer is caught ONLY by the un-notched disconect which the link trips and I get Rock & Roll!

This only took about 30-minues to do and that was with some careful thought (or lack of in the case of one disconnector)... Hope this helps!

Uppers I have for the LL at this point

At this point I have the following uppers that work with my rLL...

1. 223 (5.56 Nato upper)

http://quarterbore.com/images/qbi_bu...er_carbine.jpg

My 5.56 Upper is a fairly standard Bushmaster M4A3 upper with just a few notable additions. The upper receiver is a Bushmaster and the float tube is a Short KAC FF RAS. The Barrel is a Bushmaster 1:7 twist 14.5-inch barrel with a Phantom flash hider added. The weapon light on the right side of the RAS is a Surefire 962U and it included the tapestrip and push button tailcap. The pressure pad is neatly mounted into the TangoDown vertical grip.

2. 9mm Upper

My 9mm Upper consists of a RRA A4 upper that I had added the 9mm Case Deflector to. This upper is also using a Short KAC FF RAS tube which mounts a 16-inch Colt C MB 9mm NATO Barrel to the receiver. The barrel also has a GG&G flip up front sight. The mag block I am curently using is a RRA 9mm block. The only special thing that was needed to make the 9mm run with the lightning link is to cut the 9mm carrier to a SP-1 profile as shown in the following picture.

http://www.quarterbore.com/images/9mm_a_34_small.JPG

One problem I had with this bolt when trying out the LL came with the RRA 6-position CAR stock and the longer buffer tube that is used with these. These longer buffer tubes allowed the bolt to travel back into the stock further then a shorter CAR stock or an A2 stock using a normal rifle buffer. This caused the paddle on the link to bind and I need to get my 9mm Bolt Ramped if I am going to use the longer RRA sock with my Lightning Link in the future.

3. 7.62 x 39 Upper

My 7.62x39 Upper is nothing fancy by anybody's standard. It is an old Colt A1 upper that someone started to convert to post-ban status by cussing off the bayonet lug with a hack saw but they never got so far as to pin and weld a brake on her. To make this upper run with the LL all I needed to do was to pull the 7.62x39 bolt from the later "rounded end" AR-15 carrier and mount the bolt into a SP-1 carrier. This upper ran 100% during our test session using cheap 123-gr Wolf ammo.

Looking at the AR-10 and the possibility of using it with the LL!

Quote:

After a rather long waite my Registered Lightning Link is transfered and I picked it up yesterday from Howard Block here is SE PA (Thanks Howard!). I dry fit the link in my Post-Ban Bushmaster with my Colt SP1 Carriers and my 5.56 and 7.62x39 uppers plus my 9mm upper with my 9mm Bolt that is already setup for the link. The timing of the link seems perfect with all three bolt/carrier/uppers and every thing seems to work fine... Now I just need a trip to the range :lol:

Well, I had mentioned this prospect in the past and now that I have the link and I have an AR-10 Carbine that is on it's way from another member's out of state FFL it is time to revisit the prospect of using the Lightning Link in the AR-10 :o

I know that the AR-10 receiver is longer then the AR-15 receiver and I know the AR-10 carrier will need to be modified. From there, I simply mill the AR-10 carrier to trip the link at the proper time for a full-auto AR-10 Carbine.

The Lightning link would still be the Machinegun and it is working the same way it always did and when the link is removed the AR-10 would still be a semi-auto rifle. The Lightning link is the machinegun and the AR-15 is just a part added to the link. An AR-10 would be just a different part added to the link and the both the AR-15 and AR-10 would be ran by the link in the same way as the link was originally intended to run.

I need to dig out my Eagle Arms AR-10 over the weekend and drop the link into the receiver and perhaps get some photos and drawings about how I may try this but I wanted some oppinions from the very knowledgable here about if this is a project that has a chance of working. I am also curious if there is a snowballs chance in hell the BATFE wouldn't agree with my logic described in the paragraph above?

Somebody stop me if I did a little too much day dreaming while waiting for the transfer to get done! Yea, I already have a great system and I really need to get a 300 Whisper Upper done but the thought of a full-auto battle rifle just sounds like something I have to try as well....

Oppinions?

Quote:

Edit: I dug up my prints (which really are not so great) and I have to be honest I wouldn't want to bend and modify my link to make it work in the AK the way it looks to me like the link would need to be modified to make it work with an AK. Perhaps a C-2 SOT could play with a post-sample but I can't afford these types of games with my transferable rLL.

Anybody know a way to do this without extensive mods to the link I am all ears but I don't see how myself!

Quote:

I found some videos of AR-10s shooting full auto which really make the AR-10 look like it isn't so bad shooting!

www.bigjimsmgs.com/archive01.html

With the following videos being AR-10s...

www.bigjimsmgs.com/VIDEOS99/cap1.avi

www.bigjimsmgs.com/VIDEOS99/quickar10.avi

www.bigjimsmgs.com/VIDEOS99/youngar10.avi

I have shot a full auto M-14 and I thought it was no fun at all... this looks much better!

Quote:

I dug out the AR-10 and Bushmaster and compared them... This is going to be EASY IMHO!!! The relative distances between the AR-15 and the AR-10 FCG parts to the rear take down pin looks to be the same! Yes, they look to be very close with the only difference being the larger diameter rear takedown pin in the AR-10!

Following are the photos...

Eagle Arms AR-10 - KAC trigger on Left
Bushmaster AR-15 w/ AR-15 FCG and 9mm hammer on Right

http://quarterbore.com/nfa/ar10_ll/ar15-ar10-ll-01.jpg

http://quarterbore.com/nfa/ar10_ll/ar15-ar10-ll-02.jpg

http://quarterbore.com/nfa/ar10_ll/ar15-ar10-ll-03.jpg

Oh yea, my link does have a serial number... it was just "touched up" after the photos were taken...

You will note that my Bushmaster has the standard Bushmaster AR-15 FCG installed while my AR-10 has the KAC 2-stage trigger group. The LL will never work with the KAC trigger but my KAC trigger is just raw perfection where it sits so I only sat the link on top of the KAC unit for comparision! When I get the new AR-10 which is on it's way (I hope) I will get pics with a standard FCG installed.

Now, note that the lower should not require any fitting as near as I can tell! The two things that may be necessary is a custom disconnector to allow me to time the link for the AR-10 mainly due to the larger rear takedown pin (may be possible to notch the original) plus do a major milling of the understide of the AR-10 carrier. Otherwise, this looks just too easy!

Please don't tell me I am the first person to look at this as this really looks easy and I don't see why a DIAS would be a problem either for the same reasons! I just always assumed the rear takedown was further to the rear relative to the FCG pins but that doesn't look to be the case....

Oh well, it's 1AM here and my two older kids have been asleap for hours and I promised them a trip to see the USS New Jersey tomorrow morning.... Hope this helps and I will post more pics when I get the AR-10 Carbine that I would like to use the link in!

Quote:

As for the pictures of the BAR-10, vs the AR-10. the AR-10 will be much easier to use with the LL then the BAR-10. Compare the two pics that follow...

http://quarterbore.com/nfa/ar10_ll/ar15-ar10-ll-02.jpg

and

http://www.fdcc.us/somepics/ar10/DSC03188.JPG

Note that the rear pivot in the AR-10 is in the same location in the AR-15 and AR-10 relative to the FCG pins. Now, notice how much further to the rear the AR-10 take down lug is. What this means is that the BAR-10 would require some type of new pivot added, which I believe is quite possible, while the AR-10 should be able to be used with the link pivoting on the rear takedown pin.

Also, M60Howard here on the forums has offered to work with me on the milling and I am likely going to take him up on the offer so we can get this done. I just don't want to pull my Eagle a part but if this AR-10 carbine doesn't get here soon I may just pull my KAC 2-stage and start working with the lower on hand especially now that I have an M16A2 FCG on hand to use with the AR-10 to allow me selective fire....

Quote:

I finally managed to get an Armalite single stage trigger for the AR-10 to fit the link into the AR-10. The results look very good but there will need to be some milling! The first problem is that the larger opening for the FCG does not come to the rear far enough to allow the Lightning Link to sit up against the disconnect, much less trip it, when the hammer is caught by the disconect. See the folloiwng photo:

http://quarterbore.com/images/qbi_ar10_ll_small.jpg
Larger version: quarterbore.com/images/qbi_ar10_ll_huge.jpg

This problem can be solved by milling the receiver to the wider diameter as shown with the pencil marks on the lower.

The second problem is that the larger rear takedown pin and subsequent larger rear takedown lug on the AR-10 does not allow enough room under the lug for the link to fit into the lower. In addition, the selector of the AR-10 is at the same height of the shelf of the AR-10 so I do not think that it will be desirable to try and mill the shelf on the AR-10 to make it fit. Instead, I think I will simply remove some material from the bottom of the rear takedown lug on the upper receiver to allow the link to fit under it.

The third issue I am expecting to have with the lower is in the rear portion of the lower as the rear takedown lug goes almost to the radus cut towards the buffer tube. I wouldn't need to mill this to the rear much to give me the slack I need or I could evaluate milling the rear portion of the takedown lug.

As for the bolt carrier, obviously I need to get the lower to function with the link before worrying about the carrier becomes important. With the LL, you can manually work the link to trip the disconnect without an upper on it and I need to be able to do the same with the AR-10 lower to make sure the mods to the carrier will be correct for the timing of the link.

This still looks like a very great project! As an aside, I managed to get a M16A2 burst kit and dremel and grind it so I have a select fire kit for the Bushmaster AR-15 and the she is golden for the 9mm, 223, and 7.62x39 uppers. By using the M16A2 hammer and cutting off and rounding the rear half of the hammer (removing the hook) it works fine even with the 9mm bolt. Thanks for those that care to share with me as I slowely work on this!

The AR-47, another weapon to be driven by my LL Machine Gun!

Following are some pics of my AR-47. This is a 7.62x39 system that uses standard AK-47 mags:

www.quarterbore.com/images/ar-47_001.jpg

www.quarterbore.com/images/ar-47_002.jpg

www.quarterbore.com/images/ar-47_003.jpg

www.quarterbore.com/images/ar-47_004.jpg

NOTE: Pics are posted as URLs as the pics are pretty large!

The upper on this rifle is Colt flattop with a Colt Chrome Lined Barrel and came with one of the open "C" Colt carriers. Given that the carrier that came with this rifle will not work with the link and the AR-47 requires mods to allow the carrier to clear AK-47 magazines makes me unable to test this rifle with the link at this time. So what this means is that I need to get a new AR-15 carrier and modify it to work with AK mags plus profile it to SP-1 specifications. Oh well, everybody needs a project, right?

Update 23-Nov-2004: Well, I have not found the time to make the AR-47 shown above work with the LL but I proceded to purchase a second AR-47 lower. My second lower is targeted to work with either 5.45x39 (SAR-2) or 5.56 (SAR-3) magazines. I purchased a couple mags for each caliber and this really will be a fairly easy project. I am leaning towards the 5.45 as it is unique but the 223 would be easier as I can use a normal 223 upper with minor mods to the Bolt/carrier and the only mod that looks to be required is to the mag latch on the AR-47. Time will tell!

Select Fire question

Quarterbore,

We haven't communicated much, not really since you started this board. However, off line, I'll send you my accomplishment with the LL. It was a project we both wanted to do, although mine is now finished. Works great.
(Deliberately cryptic) Sure hope Beta comes out with a drum.

That said I have a question on the select fire kit. I just bought a 3 round burst COlt setup. After reading the following:

"It is important to realize that you need the M16A2 hammer as it has a much wider area for the disconects to catch the hammer which is needed with the two disconects this system uses. Also, I elected to leave the Burst Cam attached to the hammer. Perhaps I will later remove it and replace the hammer spring with a standard M16A1 spring but it works as it is.

Now, to make the kit selctive fire you simply notch the disconector that interacts with the selector so that when the selector is placed in the semi position both disconects catch the hammer. In this position the notched disconect is not tripped by the link and I get semiauto fire. When the selector is moved to the "Auto" position, the notched disconect is pulled out of the way and the hammer is caught ONLY by the un-notched disconect which the link trips and I get Rock & Roll! "

My question is, how much of a "notch" should I make? Do you have a better photo, maybe a side shot of what the trigger and/or disconnectors look like after you've notched them?

Also, I dumped the 3 rd burst actuator. I didn't need to keep it did I?

Thanks.

Quote:

Originally Posted by v188

Sorry, I have been swamped with some other projects... I will pull down my parts and get you some better photos... As for the CAM, I think I pulled mine out as well but I will confirm...

QB,

Any chance you could shoot some photos of the conversion?

Thanks,

Sorry, I forgot about this... been trying to learn AK speak...

I will try to get pics soon... (tonight if I get lucky!)

Here is a scan of my modified parts next to original M-16A2 FCG parts...

http://www.quarterbore.com/images/sf-ll-gp-small.jpg
Larger Pic: http://www.quarterbore.com/images/sf-ll-gp-large.jpg

I looked at my kit and I am using the M16A2 hammer spring and I did leave the burst cam in place to help with the spacing...

I hope this helps! I cut mine down in about 15-minutes but I did mess up the first set because of removing too much material... I think I described that above...

Also, the top left disconect ONLY has a noch that makes this disconnect NOT get tripped by the LL when the selector is set into the Semi position... The scan makes it look like I removed material from the hook of the disconnect that catches the hammer... It is an illusion... That should not be changed!

It looks like Lakeside is working to see if they can get there LM7 Belt Fed 22LR upper to work with the SWD lightning link... If any of you guys with LLs want a Belt Fed 22LR here is a chance to get involved...

http://208.56.123.138/Invision/index.php?showtopic=19

QB,

Just a follow up dumb question. I cut my 3 round burst kit, just like yours, except i don't have the burst "spinner" on the right side of the hammer. Anyway, it is full auto in both semi and auto. While the auto is fine, I really wanted this to be select fire. Any thoughts on why I don't get semi?

I cut the disconnect to look just like yours, same w/ the hammer.

Any assistance would be appreciated.

The only way this is possible is if your notched disconnect is not notched deep enough.

So, what must be happening is when you move the selector to the "burst" position the one disconect gets moved out of the way by the selector but the one that is remaining is still getting tripped by your link. I think you just need to make that notch deeper.

When I cut mine I pulled the link to the rear of the receiver with just the one disconect in the lower and then I notched it according to the depth that I needed so that the link didn't trip the disconect anymore.

If you need more photos I can get some for you.

I'm sorry for being so dense. I understand the principle but I'm hesitant to cut on the FSG any more without a picture or two.

If you wouldn't mind shooting a pic or two, I'd greatly appreciate it. I've read and reread your posting, and viewed the pics over and over.

I guess if I know what/where to chop off, I'll try cutting it again.

BTW, I just got my KNS LL protector. It's one tight fit, getting the rear pin pushed thru. I actually filed down the upper pin area (on the bottom) a little and now it shuts nicely. I didn't have any problems without the KNS.

Now to get it out and shooting. I haven't gotten a chance to shoot it yet. I think about maybe getting an 11" upper from Armalite, just to make more noise/flash on the line. (Don't know if I want to SBR it tho)

BTW, the LL works great in 5.56. :grin: Hope it works as well in the Armalite.

I had to work all weekend so I am just now spending some time with the family... I will get some pics a little later.

Quote:

Originally Posted by v188

I think about maybe getting an 11" upper from Armalite, just to make more noise/flash on the line. (Don't know if I want to SBR it tho)

BTW, the LL works great in 5.56. :grin: Hope it works as well in the Armalite.

remember that with the RLL, you don't have to have the receiver SBR'd. With the RLL in place, it is a MG, and barrel length has no meaning. just take the shorty upper off before removing the RLL, so the ATF won't be upset.
If you already knew that, my apologies.

I have a question. If you have more then one short barrelled upper for use with your LL and more then one lower, doesn't that make you in possession of a SBR if the short barrelled upper is not attached to the lower with the LL? I'm wondering if the ATF could try to prove that you "intended", their favorite word, to make a SBR out of the regular lower and the SBR upper even though they were not assembled as such?

Not in my oppinion... I have an AR-15 pistol as well as the rLL and I am comfortable that there is not Jury in this country that would believe that I do not have a legal and rational reason for having more then two short barrels for my MG or pistol.

Quarterbore,

Any chance you could snap a photo or two of the select fire kit? I'm a visual guy, and I still can't get my Colt Burst kit to work. Hopefully some good individual photos or group pics would help me solve my dilemna.

Thanks,

Quote:

Originally Posted by v188

Like here:

http://www.quarterbore.net/forums/sh...75&postcount=9?

If not, what would you like to see?

QB

I'm a little slow, but thanks for pointing out the extra cut you did on the disconnector. I didn't cut back the "short legged" disconnector on the top, and that's why it didn't work.

I'll be taking it out shortly to see how it works with my new big toy.

Thanks again!!!!!

Well, I haven't been back to post, but now all I get is safe/ FA/FA. No semi with the conversion. Don't know what I did wrong, but I might just buy a converted kit. I don't really use the LL, as I've got RR's, but I'd like to get it working for my eventual purchase of the MGI belt fed and 308 system.

Well, SAFE/AUTO/AUTO means you did not cut the notch in the SEMI position disconect deep enough. This means when you pull the trigger in the semi position (when BOTH DISCONECTS is on the hammer) that the link is able to pull both back!

So, the SEMI POSITION disconect, the one that gets moved OUT of the way when you put the selector in AUTO needs a deeper notch...

This really is an easy project!

Is this mod legal to leave in a semi AR or would you get in trouble w/ATF?

I have several lowers I would love to convert for use with my RLL but don't want to leave anything M-16 in them.

Thanks, FH

Also, on the RLL main page I saw a mod using AR parts only. Is that a working modification and does anyone have info on it?

I am not going to give you advise as your lawyer but I use it in my guns! There is no law that says I can not have a safety that goes SAFE/SEMI/SEMI, right?

Now, some states have special laws about no machinegun parts at all... In those states it is possible that they could argue that the trigger is still an M-16 part as well as the modified disconectors but with the bobbed hammer there is no way you could use these parts to get full auto anymore...

Well, unless you use them with your LEGAL AND REGISTERED lightning link!

Quote:

Originally Posted by Quarterbore

That seems to be the underlying thought on several boards! I love the detail you have here on RDIAS and RLL.

I have talked w/m60joe about the mods needed to get several Stag lowers to work with the Link and I am thinking about trying the AR15 selector mod as a winter project. That will at least use up several spare selectors I have on hand before I get it right!

Thanks, FH

Also - any thoughts/cautions about modifying a standard AR Bolt Carrier to work with the link? I have turned one on a standard bench grinder down to .40 on the back then used a dremel to get it to .385 and it trips the link every time in testing but I have not taken to the range yet.
I wonder did this cause a temper problem with the bolt that I need to worry about? Guess I will find out later.

I am lucky in that I have all the SP-1 carriers I need but I don't think that you will have a lot of problems with temper. M60Joe does carrier conversions on a mill and it might be worth it to send him a brand new carrier.

As fr converting a lower to use it with the link... personally, I would just buy a Bushmaster that will work right out of the box but that might be just me...

Quote:

Originally Posted by Quarterbore

I am curious how hard it would be to use a standard drill press and carbide cutters to lower that shelf by .2" and also mill out the sides a little for the Link. I could do the sides w/a dremel since there is not much to cut away.

What do you think?

FH

That would be hard on a drill press as they are not made to handle the lateral pressure like a milling machine but it is just an aluminum alloy so it might not kill your drill press?

It seems that most good gunsmiths would have a mill to do this so I would hire it out if it were me if I really didn't want to just buy another receiver. Then again, if you mess the receiver up it's not like it is that much money to replace it.

Good Luck!

Back on the board after 5 years...man time flies...

Looking for an update on the RLL w/AR-10.

I am looking at a DPMS LR-10 and am just curious would it work with a RLL and what mods if any are needed.

Thx, FH

Welcome back, it's pretty quiet these days since we were taken down by waves of spammers. That part seems to have been fixed, we had a LOT of cleanup to do, but we are spam free now.
QB did have registration turned off for a while, but not sure if new members can sign up yet.