I have a m16a1 RR pending. Really wanting a second M16. Im looking at RLL due to cost and using model lowers. I would potentially be selling/trading  1 or 2 other Subguns. Does anyone regret going with a RLL? I wouldn't mind a in spec Only or Sendra lower but those seem to have dried up lately. How realistic is breaking the LL over time? I really only want to shoot 9mm and 5.56 with my second m16. I guess I just want some real world experience of owners. Thanks.

I have two registered receiver M16s and two registered lightning links.

There are pros and cons to both but I actually really like the RLLs for the flexibility they provide and the fact that you can move them from host to host and without having to move full auto fire control parts around like you do with a DIAS.

The downside to RLL is they take more work to set up properly as you need to mill carriers back to old style semi-auto spec, you need to properly relieve the interior of the receiver(s) so the link doesn't bind, you really should use reduced power disco springs, if you want select fire you need to modify a 3rd burst fire control kit, and you need to run a "protector" on the link.  Previously 22lr was not an option but it looks like there may now be a valid option to run 22LR with a Ciener/CMMG style kit and a RLL.

So if you are mechanically inclined and have the tools to make/modify your own components (bolts, FCGs, lowers) I really like the flexibility that a RLL can provide.   However, if you are  somebody who doesn't like to work on their own guns and just wants plug and play than a RLL is probably not the best choice.  Sure you can send stuff off to gunsmiths to be modified if you like but there are not a whole lot of people who work on RLLs and each upper, lower, bolt carrier, etc. will need mods to function.

I have owned one of my RLL since 2004 and the other since 2011 and have shot the hell out of both of them.   If you follow all the historical advice on this forum so that understand how they work, how the parts and receivers need to be set up, etc. IMHO you are not going to break one.    I am willing to bet that most if not all of the RLLs that have been broken were either not set up properly and/or were not running a protector.  If you have the timing way off or the link doesn't have 100% free movement in the receiver than yeah... you can break/damage one.

Thanks. I don’t mind tinkering but I have no shop just a garage and hand tools so all the work would be a send out. That being said sounds like a non colt lower would be the better choice. I want to shoot 9mm though and dont want to damage a receiver long term. I was planning on using cmm9 radially delayed upper. I would think these would be a little less stress on the lower. Ia own semi auto colt 9mm and they are snappy and as you know rough on the FCG.

FWIW I have a have a M16 RR and a M11 with lage max11k upper with folding stock and prefer the M11 for shooting 9mm. Despite being open bolt it shoots smooth especially suppressed and is easy to clean and operate. It’s also fun to have a little variety in your MG collection. And most importantly they are $8k instead of like $15-20k. Which means you can either save the money for annoying or be able to afford a second sub gun.

Edit: sounds like you would be selling 1 or 2 sub MGs to fund it so if two M16s is what you want go for it.

The CMMG Radial Delayed units are easier on the receiver and fire control group but the handful I have had direct experience with are not super reliable in full auto and destroy ejector springs pretty quickly.  One of the guys I shoot with here in town threw in the towel on the CMMG unit as it destroy ejectors spring every couple hundred rounds and went with a blow back upper instead.    However, some folks have reported their units will run in full auto and ejector spring life seems to vary from unit to unit.   Granted they are not a big monetary investment to try out and see if you get one that work better.  Amphibian on this forum as done a whole bunch of testing and mods to the CMMG platform to get it to function and not destroy ejector springs.

I have a older LRM M16/9 integrally suppressed (but Colt pattern blowback) upper and its is actually pretty soft shooting.   I think that having a bunch of ports in the barrel really helps to cut down on the recoil impulse and rearward velocity of the bolt. If your CMMG unit doesn't have the reliability you want, I would recommend a Colt pattern blowback unit with the barrel profiled to use an MP5SD suppressor with the barrel ported.

If you do run a registered receiver with a 9MM blowback upper,  make sure that you use stronger FCG pins (Colt 9MM or KNS), the bolt has been ramped,  and one of the longer 9MM specific buffers (or use mags without the LRBHO engagement tab) so that you don't damage the receiver with the shorter 9MM bolt slamming into the LRBHO.

Good luck.

I need to reach amphibians stuff again to look at his mods and such. My uzi is still my go to 9mm. Really it does everything I want in a sub gun. How about the .22 full CMMG kits. Any issues running them long term not the lower besides getting them really dirty? If anybody sees good deals on non colt lowers PM me.

http://www.c3junkie.com/?page_id=164

Have you noticed any accelerated wear on your receiver after trying all the setups?

Nope

Reading your blog posts it seems like the extractor spring issues is going to make the radial delayed upper not a viable long term or high volume setup? Am I getting the correct take on this? Have others used this setup and has it been durable?

As posted by jbntex above:
I'm hearing the same thing.  ONE guy posted on here about a year ago that he had 3 or 4K through his on the original ejector spring with no issues.  He was running full auto and suppressed.  
I haven't seen or heard anyone else claiming that.  

You have other people posting here on AR15.com that even in semi they have failures around the 1K mark like I did.  

Locally, I know several people running them in full auto that have the same failures around the 1k mark....while I know some guys that have them in semi and have 3 or 4K with no issues.

It seems to be hit or miss but again, I don't know anyone locally that has one that runs 100% after 1K rounds in full auto.

As you can see on my site, http://www.c3junkie.com/?page_id=221
I've tried various springs/tricks and nothing seem to surpass the CMMG ejector springs.  I did just get an inconel ejector spring that is supposed to last longer than a standard music wire spring.  I measured the strength and it is about 6lbs so should be enough for reliable functioning but I haven't tried it yet.  

All that said, I would still use the CMMG RDB on a transferrable lower vs a straight blowback and worst case replace the ejector spring every 1K rounds.  Best case is you have a fixed ejector fabricated like I did and have none of these issues.

As a side note, I had high hopes for the Mean Arms roller delayed setup but haven't heard a peep about it for several months.

Thank you for information. I do remember seeing that roller delayed upper at shot show video but not a peep since then. Would best of both worlds. I am strongly looking at maybe a HK sear instead of second m16 given the 9mm limitations. I would still probably get a CMMG upper for the colt I have pending.

Every single person that I had shoot my tuned CMMG side by side my MP5 has liked the CMMG better.
I was really surprised.

MP5 is obviously the proven platform but I really like the LRBHO, ergonomics, available accessories (like nice triggers like the Geissele SSF) and tuneability over the MP5 family.  

Of course the correct answer is to get both.

If you have the funds for an HK Sear over another M16, I would highly recommend an HK sear over a second RR M16.  This is coming from the POV of somebody with four M16s and three HK sears and is pretty committed to both platforms.    IMHO the HK sear really shines with the MP5 platform vs. the M16/9 and an MP5 SBR host built off a HK94 receiver is pretty close to a 100% plug and play combination and arguable the world best 9mm submachinegun.  An HK sear also opens up a whole world of different HK hosts including 7.62x51 guns in both mag fed and belt fed options as well.

If I were in your position, I would agree with you and at least buy the CMMG upper, play with it on your existing M16, and see if it meets your expectations before plunking down $20K and waiting 6 months or more purchasing another M16 to dedicate to 9MM.

Either way, I don't personally know anybody who bought an HK sear and ultimately "regretted" it.

I have both platforms as well but honestly only like the HK platform for 9mm.  Even then it still shoots too fast for me to consistently pull singles.  As a tinkerer, I'll take the M16 over an HK sear any day.  Very easy t control the cyclic rate while you are pretty much stuck with whatever works on the HK platform and don't mess with it.

I also really like shooting full auto 22LR and other than the HK G3 conversion, not much to choose from there.  You have more .308 options with the HK but that really doesn't appeal to me.
I've got belt fed 22LR, 9mm and 5.56 for the M16 platform and not really interested in going to a larger caliber belt fed.

I have a zenith MKE and an OMEGA MP5 SBR. Is the OMEGA full size MP5 likely to be plug and play with a flemming 4 pos sear pack?

I don't think you can go wrong either way as the M16 and HK sear platforms are probably the two most versatile machineguns you can get.   That said, I find the HK platform more mechanically interesting to work on vs. the M16 platform. I also really like the 7.62x51 and 7.62x39 HK hosts vs their M16 peers but still have an M16 RR set up in 7.62x39 (with one of your adjustable gas blocks ) and a Colt LE901 SBR set up to run a RLL.   I totally agree the M16 is the winner in the 5.56 category but still have multiple HK 5.56 hosts as well.

If this was a first machinegun for the OP I would agree, get an M16 over the HK Sear, especially if you want a platform that is generally more end user friendly and doesn't require much in the way of specialized tools to work on.

However, if you already have an M16,  to me the logical choice between either another second M16 RR or an HK Sear, the HK sear makes more sense and opens up a whole new category of hosts platforms to explore.

If the OP still wants a CMMG 9MM upper to play with, he doesn't need a second M16 RR to go down that path.

I could maybe see the argument for a second M16 as a RLL or RDIAS as that opens up the possibility of all sorts of full custom builds on the M16 "sear" that you can't do with a RR M16.   Stuff like HK416 clones, magwell-less SAW box lowers for a Shrike, buffer-tube-less 22lr builds, dedicated pistol caliber lowers, AK mag or mutant x39 builds, etc.

The Zenith wont be as it has a full auto carrier block in it.   Assuming the Omega runs in semi-auto.....and has a full auto carrier installed, and the front shelf isn't all wonky/out of spec..... than yes, it should be plug and play.

If you are looking at an HK sear, I would personally stay away from the 4-Position burst packs.    I have my three HK sears installed in one of each type of pack,  one sear in an older 0-1-A "SEF" pack, one sear in a 0-1-A ambi "Navy" pack, and one sear in a 4-Position 0-1-3-A pack.  However, if forced to keep one....the sweet spot to me is the 0-1-A ambi "navy" pack.   While the burst packs offer a "burst" mode the tradeoff compared to 0-1-A isn't worth it.

Burst packs are really complicated to take apart and put back together, so if something breaks inside (and there is a lot more something to break inside a burst pack)...unless you are really confident in a hour long disassembly/reassemble procedure you are not going to be buying an internal part and replacing it yourself.  That means potentially shipping it off to somebody to repair vs. an SEF or 0-1-A ambi which are not that much more complicated than an M16 FCG and most end users can repair.

Even a partial disassembly on a burst pack for a deeper cleaning is much more challenging.

Also changing the hammer springs (pistol to rifle to beltfed) in a burst pack also requires a couple tools (one to push the spring donut bushing forward and one to hold the spring back to allow the donut bushing to be removed) If you forget to bring those tools to the range with you, you are not going to be swapping the hammer springs around if your hosts require the proper hammer spring.  With an SEF or 0-1-A Ambi you can easily swap the hammer springs around using nothing more than a simple punch or the tip of a rifle round.

Burst pack disassembly and reassembly procedure:

https://www.youtube.com/watch?v=bVbs7RCvLek&t

https://www.youtube.com/watch?v=ZQB9JrcjlKo

With the 0-1-A ambi "Navy" pack you get all the benefits of the upgraded ambi grip frame ergos over the SEF ( better selectors, nicer grip, picto markings, etc.) but with none of the complexity and cost downsides of the burst pack.

My 7.5" 7.62x39 M16 configurations have always been one of my favorites.

I love being able to tinker with various cyclic rates on the M16 family using the latest buffers, springs etc.   Just don't see much innovation on the HK platforms.

+1 on the RDIAS

I have contemplated the RDIAS but since I shoot mainly PCCs and I have mp5 and mp5 accessories already it makes sense to me to go more towards that route probably. The sear I am looking at is already in a burst pack. Im happy to leave as is for a while and just run mp5 variants for a bit. Rifle caliber HKs down the road. I have a hard time selling any gun let alone transferables but I so many open bolt iron sighted guns I'm craving more modularity and modern ergos. The HK sear would also be nice to have a MG and not worry so much about running it hard since the receiver isn't registered and paint, dings, scuff and stuff aren't taking thousands off the value. I actually run my full autos in classes locally from time to time. The sear is nicely protected in its housing and people say they are quite durable. Really enjoying the feedback from users here.

Do they have a .308 magwell for those lowers?

They had a prototype at one time but I'm pretty sure it was never released....they tried to cram everything into the same length of a standard AR...so no LRBHO.  I wish they would have made a longer magwell like the Colt 901 or DPMS G2.

Maybe you could have one custom cut.  I think I would go for it if I had a DIAS instead of a RR.

ETA: Can you put a DIAS in a 901?  Might be easier to just buy a different host.

Yes, the 901s are cut to SP1 spec internally (low shelf with no sear block) so a RDIAS will drop right into the receiver and work with either a 5.56 or the 7.62x51 upper.

A RLL will also drop right into them as well using a standard paddle but you do have to mill the 7.62x51 carrier back to trip the link as the standard 7.62x51 carriers are M16 full auto pattern.

Thanks.  I was thinking that might be the case.  It would be fun to have an RDIAS.

I think I have made my decision to go with the Flemming sear pack. Anything particular I need to lookout for?

The Fleming H Series sears are pretty bulletproof as long as they have not been messed with.

If you are buying a Fleming sear installed in a burst pack as you mentioned above I would double-check to confirm how the sear/burst-pack installation was done.   An HK conversion sear natively can't be installed and work in a burst pack as all of the burst guts are physically in the way of where the normal semi-auto elbow spring pin would be that an HK conversion sear installs on.

As a result the conversion in a burst pack is done by welding up the factory autosear hole in the triggerbox and redrilling a new auto-sear pin hole ~1mm vertically lower in the pack (legally making the pack no longer a factory full auto pack so the front of the pack can be notched to clear a semi auto shelf) and then installing the conversion sear on this new autosear pivot hole.

The problem is that the factory full auto sear pin and the now slightly moved conversion sear pin hole is way too far forward in the pack for the sear to engage a standard full auto hammer.

There are two way that gunsmiths have historically taken to resolve this "gap" between the ledge of the conversion sear placement in a burst pack and the auto sear trip ledge on the hammer.

1. Weld an extension onto the conversion sear itself.

2. Use a proprietary conversion sear burst pack hammer that has a much larger sear catch ledge on the front of the hammer.

Back to your original question, what should you look for?  I would absolutely make sure the sear has not been modified with a part welded or soldered onto it.

Other than that I would check to see how the conversion was done.  How clean is the weld up of the factory full auto sear hole and the new drilled conversion sear pin hole,   is the conversion hammer welded up or is it one of the more modern billet "conversion burst" hammers and how does the timing of the hammer look.

If possible it doesn't hurt to make sure the actual sear in the pack serial number matches the paperwork as a CYA on a $30K purchase.

Granted, it can be difficult to read the Sear SN# through the semi shelf notch cut in the front of the pack when installed even on an SEF or Navy pack and the serial numbers are very lightly electro-penciled between the sear legs.  It can be even more difficult on a burst pack given how the sear is installed and less material may have been removed from the front of the burst triggerbox vs. a typical SEF or Navy pack conversion.

However, its worth taking a look and if needed use Q-tip to clear away any grime/git from the serial location on the sear and most smart phones nowadays have a lighted magnifier function that may make reading the serial number easier.

Good luck with your purchase, HK sears are awesome.

There is a lot to learn still. All that kinda makes me wonder if a RDIAS would be easier option. There is a broached aluminum RDIAS that might also be in price range and I could try various 9mm AR setups but nothing will beat mp5 for smoothness. This is from a major dealer so I have more confidence in making sure everything is registered correctly.

I would still suggest getting the HK Sear if you already have an M16.  Those two guns will give you huge flexibility and a vast number of different hosts you can play with.

On the HK sear front, a lot of the complexities I listed above all go away if you get one installed in a SEF or Navy pack.   Burst pack installs are not "bad" per say but for somebody who is new to the platform the SEF or Navy packs installs certainly make things a lot simpler.

That said it certainly doesn't hurt to start doing some reading and research on HK Sears, how they work, etc. so get up to speed and if you have any questions there is plenty of knowledge on this forum to navigate you through any questions you may have.

Quoted:[/b]I disagree.  I put my tuned CMMG RDB up against any MP5.  However, as I've posted many times, an out of the box CMMG RDB is NOT as smooth as an MP5.
Again, every single person that I've had shoot both side by side has said they liked my CMMG RDB better.

My setup below is using my preferred setup:  A5 tube, Tubb flat spring, Kynshot R5007 Hydraulic buffer and modified 5.45 bolt to further delay the action.

I would go for a RDIAS over an HK sear....that is just me.  Mine has truly been drop in with no timing necessary.  Hosts are cheap and modern.  Easy to get parts and work on with just a vise.

Im fairly knowledge on transferrables except for HK sears which have some details I'm working on. This is a Flemming sear installed in burst pack as I have been told and wont have full photos until dealer has it for transfer. I guess I just want to make sure I don't get something I really don't want but unless the sear itself has been modified everything else can be adjusted with fixing pack. I assume modified non "standard" flemming sears are fairly rare and most should good, correct?

JBNTEX

your knowledge never fails to amaze me

knowing what I know now if I was to start over I would've simply bought a RDIAS and a registered HK sear.


Registered receivers are super nice and give you a lot of happiness to look down and see your pony.

I tell you that to tell you this I was at a machine gun shoot and someone is shooting one of those 32 cal scorpions, And a case came flying over and hit the side of my registered receiver Colt m16. It took some of the park off and I felt sick

if that would've happened in a host gun i'm sure it would not have bothered me at all but it had a $25,000 gun


That said you need to figure out what makes you happy A registered receiver Or being able to shoot full auto without fear of damage


If I were you I would buy the drop in auto sear and the HK and sell your registered receiver and Call it a day

My RR is a SAW. I don't want to feel bad about scuffs and scratches.

Not to get an a dick swinging contest but how much is your SAW worth and is it transferable

No sense in comparing apples to donkeys here

Generally everything I listed for concern on a burst pack purchase can be fixed/reworked/replaced other than if the sear was modified.  That said welded/modified Fleming sears for burst installations are rare....but they are out there floating around from a time when sears were a couple hundred dollar items and nobody really cared if the sear was modified to work in a burst pack.  If the sear is installed in a SEF or Navy pack there is no need to mod them as that is what they were designed to "drop into" using the semi auto elbow spring pin location......but to work in a burst pack, something (either hammer or sear) has to be modded as the geometry won't work otherwise.  So on a burst pack purchase its always prudent to confirm how it was done.

HKPro has a really good tutorial in the NFA section on different sears/packs and I am pretty sure they have a pic of a couple of modified sears.

The good news is its really obvious if the sear has been modded assuming you know what a non-modded sear looks like and the internet is full of uninstalled Fleming conversion sear pictures.

I think he means his M16 registered receiver is an Olympic Arms forged receiver that Oly sold "rebranded" with the double-circle SAW logo and was subsequently converted pre-86 into a transferable M16.  

Similar to how PAWs or Palmatto Olys were also rebranded for a 3rd party on the magwell but still say Olympic Arms above the fire control group pins.

Not that he has a "SAW" as in a M249.

Attached File

Yes that makes much much more sense

Like I said before your knowledge far outweighs that of most people here


thank you

jbntex is correct, I wish I could afford a transferrable M249.  I thought the RR in front made it fairly clear I was talking about an M16

haha I thought you were an SOT with a posty SAW

I don't care it my SAW gets scratched!!  

Sorry frost