First off, I know this has probably been "done to death" and there's probably a reference link on Quarterbore's site or something, but I was initially interested in a M10 or M11 and was talked out of it and talked into a rifle caliber C3/NFA gun and was trying to decide between an AC556 and FN FNC, but after reading about all those I have taken it to the next level and will soon have the funds to move into the "M16" category.  Now, my question is:  which way should I go given my situation;

Registered Lightning Link
Registered Drop-In Auto Sear
Registered Receiver

?

My situation is that I have NO full auto stuff, but I do have a LOT of AR15 stuff.  I have about 20 complete AR15 uppers and 10 complete AR15 lowers of various manufacture (DPMS, Eagle Arms, MEGA, VM HY-TEC, Bushmaster and Rock River Arms).

My understanding is that if I go with the RR or RDIAS, I'd have to get M16 bolt carriers for all the uppers I want to use with the NFA/C3 lower, and if I went with the RDIAS, in addition to bolt carriers, I'd have to get a fire control group for the lower I want to use the RDIAS in, and remove it when I remove the RDIAS, but the advantage is that I could use it in a *new* lower as long as it didn't have the sear block (shelf) in there.  The advantage of the RLL (as I understand it to be) is that I can use it in ANY AR15 without changing any parts and it will work fine; the disadvantage being that I lose the ability to use semi-auto while it's in there (unless I do some sort of modification to it).

Can anyone help me outline the pros and cons to each option?  I am THIS close to forking over the $$ and since I will only be able to afford one, I want to make sure I mke a wise decision.

Thanks!

.

I think the RR is the way to go, as you can keep the M16 fire control parts in the RR. With a RDIAS, you'll be swapping AR15 control parts and M16 control parts in and out as you move the RDIAS from one lower to another.

The RR also solves the issue of having extra sets of M16 parts around when you do own AR15s as well -- in reality, you'll only need one set, installed in the RR, and an M16 bolt carrier group.



Jeremy

Remember...the RR blows up.... hard to repair...costly to repair...if the lower blows up with a DIAS or LL in it...pick up the DIAS  or LL .. buy another $90 lower.

I have a LL, but a DIAS is the way to go in my opinion and I would have got a DIAS over a LL if money would have permitted.  However, I would get a DIAS over a RR anyday!

RDIAS,
Slap together a cheap host gun for $500 and burn it to the ground with dirt cheap ammo. C-mag dumps, burn the front hand guards off, Run 10, 000 rounds threw the rig without cleaning, it doesn't really matter. If the Host rifle wears out or just blows up, your not going to hurt the sear, and can have another host rifle up and running with the RDIAS in a few minutes.

RLL
Paddles bend or break after a few thousand rounds, but still can be swapped from host to host. Almost as good as a Rdias.

RR,
Total Range Queen.
Blow one up, and you will be looking for a smith that can perform special magic getting it welded back together.   Plus, don't plan on seeing the receiver for a long, long time while it's being fixed.

Thanks for the replies guys.  I was leaning towards a RLL (1st), and an RDIAS (2nd).  Out of curiosity, the RLL is a thin piece of metal...  if it ever broke, can it legally be replaced?

Yes...please don't buy ANY RRs.  This rush to buy RRs has jacked the prices completely out of sight.  BUY ONLY RLLs or RDIASs, as I want to be able to get my POS RR for a little better price down the road.  It's just a hunk of crap & a range queen, but what do I know.  Please save the RRs for us idiots.

Thenk yew veddy much.

In another thread I said I wouldn't trade my rLL for an DIAS and I still feel that way but to be honest if I had the abuility to handle a little more debt I would be buying a DIAS or HK Sear.  Reality has struck that I can't do that again...

Here are a few of my oppinions...

Lightning Link

Now, you mentioned just swaping the LL into any lower and using it with any upper.  This isn't quite correct as you do need an SP-1 carrier as opposed to 99% of the AR-15 carriers out there.  In addition, the link will only work with some brands of lowers.  Obviously the cariers and lowers can be modified to work but I wanted to correct this point.

The Lightning Link is still the cheapest way to go and I have set-ups now for the 9mm, 223, and 7.62x39 and as I assume you know I am looking at the AR-10 when I can.  I have also setup my Bushmaster lower with a select fire kit and frankly a LL with a select fire kit shoots and handles exactly the same as a RR.  What I like with the LL and DIAS best is the fact that the MG itself would be almost impossible to break and add a cheap new lower and I have a brand new gun.  I also like how the LL and DIAS can be moved from lower to lower which allows these two to be used with an AR-15, AR-47, and with any luck I hope to get the AR-10 running with the LL as well.  The LL has a slight advantage here as the LL is easier to time and easier to swap then a DIAS which may need shims or adjustments.

DIAS

The DIAS is with very little doubt the best answer.  The DIAS will do everything my link will do plus it works like a traditional GI sear which will allow you to swap out M16 FCGs so you can try the M16A1, M16A2, and M4 enhanced groups.  The DIAS will also work with a Ciener 22 conversion and after having a RR with a 22 conversion where you can shoot a few thousand rounds for less than $40 it really is nice having that option.  The lightning link looks to be a nightmare to make work with current 22 conversions but lucky for me I do have another NFA toy that can do 22LR for me.  The DIAS, especially the steal versions, are without doubt the strongest MGs you will find.

RR

The Registered receiver is pretty cool as it looks like an M-16, it is milled like an M-16, and it has the parts of an M-16.  The differences between the various RRs make it tough to describe all of them but if we go with the general mil-spec forged lower as an example.  Such a lower is very strong and it will do anything the LL or DIAS will without problem.  The only difference here is that you are stuck with the single lower but next to an H&K sear pack you still have the most versitile MG option you can get.

So anyways...

The good news is you picked excellent choices.  The bad news is that others have been here for some time driving up the prices.  You can not go wrong with any of these options and while I am very happy I got my rLL and I really wouldn't trade it for DIAS I would still tend to agree that the DIAS may be the best item of the three to have.  Personally, I like the LL and DIAS over the RR as both do give you multiple MG systems because of the different receivers they can be used with.

In my case, I have three other MGs including a Vector UZI, SWD M11/9, and a SWD M10/9.  FWIW, one of the most affordable and yet most versitile weapon systems is still the Vector UZI.  I run mine in 22LR, 9mm, and 45 ACP but it will also run in most any pistol cartridge.  I still like the AR-15/M-16 options better but man is the UZI a fine system that deserves more credit then it seem to get.  The M11 and M10 are honestly guns that I just got because of their potential in the future as there were various uppers comming out for them and I hope that one day I can get a SAW style upper for one of them.

Good Luck... it isn't an easy decision!

EDIT:  I think you would never be able to break a link or DIAS.  They may bend if you had a major KABOOM whick likely would remove your whole head anyways but your Widow would be able to pound it flat and get to sell it to the next guy  

(Edit 2 to swap the smileys)

Let me start by saying that I have a number of RRs and one DIAS, so I have no bias towards either one.

As far as the RRs blowing up, it's an oft cited reason for DIAS superiority but seems to be a myth as far as I can tell.  Others have challenged someone to cite an M16 kaboom  - no one has found one yet as far as I know.  Even if that does happen, a RR can be repaired.

RRs run pretty well with no tweaking -- no "catching the DIAS" when you break open the upper to clear.

DIAS allow you to switch lowers, but frankly, I find switching the M16 fire control parts (which must stay with the DIAS) to be such a PITA that my DIAS semi-permanently resides in a Colt 9mm carbine.  I use a RR for .223 shooting.

In sum, you really can't lose with either, but sad as it may be, you will be paying significantly more for a DIAS these days than a RR M16 lower.

Originally Posted By Phil_A_Steen: Others have challenged someone to cite an M16 kaboom  - no one has found one yet as far as I know.  Even if that does happen, a RR can be repaired.

One:  quarterbore.com/ar15m16/ar15kaboom2.htm Actualy two if you read the linked article...

Note:  Not that I would use one example to make up my own mind!  The bigger issue is that you will eventually wear out trigger pin holes.  Yes, they can be fixed but I would prefer to replace the lower with a new one by moving the sear or link to a new lower....

Note:  Not that I would use one example to make up my own mind!  The bigger issue is that you will eventually wear out trigger pin holes.  Yes, they can be fixed but I would prefer to replace the lower with a new one by moving the sear or link to a new lower....

Well, you'll eventually wear out the flapper on a DIAS too... the key word being "eventually". After 1000K rounds is still eventually.

There should always be a great deal of trepidation when you're shooting your $10K+ investment, whether it's a RDIAS, RR, or RLL. That's a lot of money to be exposing to possible destruction. By using quality factory parts, keeping up maintenance, and using quality ammunition, the danger of KB is greatly reduced. Or, if you have an M16 but you're afraid to use it for fear of damaging your investment, you would have probably been better off just lighting that $10K+ on fire in the first place. An unshot machine gun is a waste of money.


Jeremy

Do you like to tinker?  I have yet to see a RDIAS or RLL run when first installed.  It's usually the 4th or 5th time at the range that they actually run right.  And God forbid when you get a new upper; you do IT all again.

Originally Posted By Hail Mary: Do you like to tinker?  I have yet to see a RDIAS or RLL run when first installed.  It's usually the 4th or 5th time at the range that they actually run right.  And God forbid when you get a new upper; you do IT all again.

Maybe we should shoot together sometime....The only upper I've had to tinker with was the 7.62x39, but later discovered it was a bad barrel and not a timing problem.

Jtb33, I could only afford one machinegun myself, and chose an RR. Here's why I recommend the same to you:

1. You have 20 AR-15 uppers and can swap them on an RR to your heart's content. You can use the same M16 bolt carrier in all of them and just use dedicated bolts for each upper if you like.

2. You won't have the timing issues that may or may not be associated with swapping uppers around with an RDIAS or RLL.

3. An RR functions in both semi and auto, so no need for the other ten semi-auto AR-15 lowers. Sell them and buy another machinegun and suppressors. It would be very difficult to swap an RDIAS or RLL into each and every configured rifle you have.

4. You stand a better chance of winning the lottery than blowing up an RR. Use only quality ammo and you will be okay.

If you only had one or two uppers, I'd say a RDIAS or RLL would be fine, but you did mention YOUR specific situation and I feel that it warrants an RR.

Hmmm.  Seems like this is leaning towards RR.

TonyK, why don't we make a DIAS-LL-RR pros and cons thread (with a poll) and tack it?

Originally Posted By Phil_A_Steen: Hmmm.  Seems like this is leaning towards RR. TonyK, why don't we make a DIAS-LL-RR pros and cons thread (with a poll) and tack it?

Please do, and include a lot of detailed information about timing the RDIAS and RLL.  I read both sections at Quarterbore's site, but it's still a little confusing.  I'm hoping (read: praying) that by this time next year I'll have the money to buy an M16 or one of the conversions and knowing what I will be in for at that time would be a huge help.  Of course, by then M16s will be commanding 20K, so I'll probably end up just blowing the money on a hotel room full of hookers in my frustration of getting so close but still being so far.  Sigh.

Lightning Link Wins!!!!

100% Lightning Link
0% Registered Receiver
0% DIAS

Oh my... only one vote....

Edit:  In case I didn't make it clear earlier...  any of the three are great choices.  I just consider the LL and DIAS to be more versitile much like an H&K Sear Pack because of the abuility to move the MG to different Title 1 guns.  There just isn't many other options like this and that is why I would want either the DIAS or LL over the RR.  Even with that, the RR is still more versitile then most any other MG you will find...

You have to vote to see the results.  For people like me with no informed opinion you should add a "no opinion" vote.

Which is the "better" buy/option for full auto?

--------------------------------------------------------------------------------

[ 6 ]  Registered Lightning Link  [ 23.08% ]
[ 12 ]  Registered Receiver  [ 46.15% ]
[ 8 ]  Registered Drop-In Auto Sear  [ 30.77% ]

--------------------------------------------------------------------------------
Total Votes :: 26

Thanks

[ 7 ]  Registered Lightning Link  [ 19.44% ]
[ 14 ]  Registered Receiver  [ 38.89% ]
[ 15 ]  Registered Drop-In Auto Sear  [ 41.67% ]

--------------------------------------------------------------------------------
Total Votes :: 36

Just click on vote without selecting an option.

well the way like at it is whatever you decided still beats not having a MG.

ill take whatever of the 3 i could get if i had the cash. I would take a m16a1 over a DIAS only becouse I think it would be cool to have a real m16 but if i had the cash to spend on a MG now I would take whatever i could get my hands on since like i said a RLL beats not having a Registered anything.

Heres a link to my argument a while ago in favor of the RDIAS, at the time RR were around 6.5K and RDIAS were 4K.

edited in because the link expired

Whenever someone chimes in here (or other boards) wanting to know about purchasing a M16 the almost immediate and universal response is that their best choice is to buy a registered receiver and the next choice (if you could not afford a RR) would be the Registered Drop In Auto Sear. After doing my own research I came to a different conclusion and went the RDIAS route (and have been very happy with my choice). Here is my own argument in favor of the RDIAS. Feel free to disagree, Flame suit on…

Advantages of a RDIAS over a RR:

1. Cost, OK, when you include the cost of the rifle they go in then they are not much cheaper than a RR but for someone that already has a rifle….

I often hear people say that a RR is a better investment or holds its value better. My own observations are otherwise. If you could go back to 1984 with $800 in your pocket would you buy a $600 rifle + $200 in tax stamps, or would you buy 3 $50 DIAS and $600 in tax stamps? The gap is narrowing, and because the DIAS requires a little less investment it has a broader market. Subsequently if the NFA guns are ever outlawed, you have a smaller loss. As RRs start to show age and wear they loose value.

2. Cosmetics, the owner of a DIAS doesn't need to baby his rifle like the owner of a RR. Slide a RR across a rough concrete floor and you probably reduced the value by a thousand bucks (or you are going to refinish it for at least several hundred + the time and paperwork it takes to send it off). Do the same with a DIAS host gun. no big deal you can replace the lower with a new one for around $125 (little down time). The host gun will also look military spec. (Small pin, push pins, raised mag fence ect) unlike some conversions.

3. Kabooms, Blow up a RR and your going to be out some big bucks and down time for repairs (if possible at all, John Norell is no longer doing this kind of work). A RDIAS would probably survive the kaboom without damage (again just replace the host firearm). This also includes other kinds of damage from accidentally running over the rifle with a truck, to house fires (don’t laugh I’ve read threads on both)

4. Repairs, You could build a DIAS from scratch with hand tools so I would suspect you could find a way to repair one locally (while you wait) with minimal expense. As long as you retained the section with the serial number you (or a local welder or machinist) could "weld" it back up from any damage. No refinishing necessary as the part is hidden inside the firearm. If you need work done on a RR you are going to want to send it off to one of the experts requiring paperwork, time, expense and refinishing. Less moving parts in the DIAS means less likelihood of something going wrong or wearing out in the first place

5. Storage, You can put a DIAS in a safety deposit box. You could probably throw it in a kitchen drawer and no one would steal it because 99.999% of the population has no idea what it looks like.

6. Low Profile, A firearm with a RDIAS has no visible auto sear pin so it doesn't excite unwanted attention at a “semi only” range.

7. Materials and advancements, Polymer lowers, Carbon fiber lowers, Ceramic metal matrix lowers, stainless steel lowers, titanium lowers, lowers with specially designed magwell for different calibers/magazines, experimental lowers. All possible with a RDIAS.


Advantages over a LL:

1. The RDIAS is structurally more sound. My observations are that the RDIAS is from an engineering point of view as sound as the sear in a RR.
2. The RDIAS can use aftermarket fire control parts designed for the M16 (at least mine works great with the Knights 2 stage M16 trigger). The RDIAS would also work with a burst trigger (should you want one).
3. Select fire capability (without add ons).

Disadvantages of a RDIAS:

1. Collect ability, Historical examples of the M16 have greater value to collectors. The advantages of the RDIAS center around firearms intended to be used and abused (and be easer to fix than RR).
2. Timing, To be fair I have heard of issues with having to time a RDIAS to a particular upper, however it is my understanding that once timed they run fine.
3. Lowers don’t say “M16” and are not marked “Safe, Semi, Auto” unless you pay someone to do the extra engraving.
4. Will not work with the purposed open bolt model of the SHRIKE. They will work with the purposed closed bolt version however.
5. More expensive than a LL, (the LL can also drop in a AR without M16 parts).



Remarking:

Those were the days. Before Geoffrey A. Herring snooped his nose in on M16's driving the price up!

Sammy

Originally Posted By Theo: Heres a link to my argument a while ago in favor of the RDIAS, at the time RR were around 6.5K and RDIAS were 4K. www.ar15.com/forums/topic.html?b=3&f=14&t=143540 Remarking: photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=27279

What are the current prices for each? Also for a Vector Uzi?
Great thread! Thanks Gang.

Johnny C!

just a note on "kabooms",    been fortunate (?) to see 3 such incidents
2 were a fellow reloader who, somehow, got some pistol powder in his 223 reloads, i guess he didn't clean out is dillon good enough, however he was ok, toasted his upper receiver, barrel and lower were fine,,,
3rd involved an army reserve m16, had a sqib load and pulled the trigger on the following round,
again toasted the upper, bolt, charging handle, magazine, and peppered the shooter, but the lower
was left in service
hope this helps,
my vote is on a rr, had one for years, never had a problem,

Didn't Machine Gun News have an article about a M16 "detonation" at Knob Creek..?

Mike

I've been offline for a little but one thing to add on this about the RLL. Someone gave me one for repair, the back end where the paddle goes broke. These thing are tempered spring steel and very thin. This link need to be welded which will take the temper out of the steel, there's no way to re heat treat it later which makes
it non repairable. A DIAS can be welded Allum or Steel so I have to figure how to get it fixed.  Howard

I'm a big fan of my DIAS. Everyone always asks where I got my cool reciever. That's one thing people don't take into account - you can have a custom reciever built with your personal logo, funny sayings on the side, whatever. A DIAS really gives you more options.

I _have_ egged out the holes on my reciever, too. 9mm SMG kit w/unramped bolt did it. It still runs (for now) but I'm going to have to replace it in the near future. No problem, I'll just toss my reciever.

I also like the fact that I don't have to baby my rifle. It's scratched to shit - bouncing off my belt buckle, other guns when I transition, my surefire on the back of my belt, etc. When I get tired of it being ugly, I can just swap out all my parts, and in a matter of minutes I have a brand new M16.

I also like it for when I travel. If I get on a plane, I pop the DIAS out and put it in my carry-on, pocket, whatever. If some idiot decides to lift it, now he has a non-functioning weapon. and I'm not out 10 grand.

Doc

Originally Posted By DoctorNo: I also like it for when I travel. If I get on a plane, I pop the DIAS out and put it in my carry-on, pocket, whatever. If some idiot decides to lift it, now he has a non-functioning weapon. and I'm not out 10 grand.

Is that really a good idea?  Under TSA rules a DIAS is considered a firearms part and is subject to confiscation, and you are subject to civil and criminal penalties for carrying it into a sterile area.

If you can somehow explain to me how a DIAS can fire a round or is a real firearm or violates any of  TSA's rules, I'd like to see it. If they ask - it's a charm my father gave me. It's a machine part for my work. It's a minature replica of a part we make ... blah blah blah.

If they confiscate it, big law suit. At some point, LOGIC has to take over in this world.

A DIAS is only papered as a firearm to the ATF because of its NFA status. If you did not have a registered DIAS, you could buy one at a gunshow with no paperwork. It in no way can fire a round on its own, so the argument that it is a firearm is ridiculous.

Doc

Originally Posted By DoctorNo: If you can somehow explain to me how a DIAS can fire a round or is a real firearm or violates any of  TSA's rules, I'd like to see it. If they ask - it's a charm my father gave me. It's a machine part for my work. It's a minature replica of a part we make ... blah blah blah. Doc

I see the logic in your position, but unfortunately the DIAS is considered a machinegun under the National Firearms Act.

Further, TSA rules ban any firearms part, regardless of whether the part is a "firearm" by itself.  So you couldn't carry on a disconnector, bolt, trigger, autosear or a DIAS regardless of whether it can chamber a round and fire it by itself.

No one ever accused a government employee of intelligence:  www.ar15.com/forums/topic.html?b=8&f=13&t=185027

Well, the guy who tried to carry on the buttstock in that other thread was completely in the wrong.  From TSA's own website:

Firearms and firearm parts must be checked with the air carrier as luggage.  Firearms and firearm parts are prohibited from carry-on baggage.

www.tsa.gov/public/interapp/editorial/editorial_1666.xml

Originally Posted By Phil_A_Steen: Well, the guy who tried to carry on the buttstock in that other thread was completely in the wrong.  From TSA's own website: Firearms and firearm parts must be checked with the air carrier as luggage.  Firearms and firearm parts are prohibited from carry-on baggage. www.tsa.gov/public/interapp/editorial/editorial_1666.xml

I posted it as an anecdote to demonstrate why Doctor No should consider not keeping his DIAS with his carry-on.  A DIAS is not capable of firing a catridge on its own, but neither is a  buttstock.  Both are considered firearm parts, and as per TSA regulations, prohibited from being placed in carry-on baggage.  That being said, I don't think TSA confiscates items, but requires a passenger to voluntarily surrender prohibited items if that person wants to get on a plane.

Originally Posted By tony_k: If you get struck by lightning, or wander into a nuclear reactor unprotected, with either an RLL or RDIAS, they can be destroyed or contaminated beyond use. I only mention these possibilities because they are as likely to happen as you are to "blow up" an RR beyond repair.

In the case of the rLL in the nuclear reactor .... if you can get the rLL back out , run the Form 5 to the next of kin, then the rLL being a simple steel item, can with a lot of work remove most of the contamination, (may still need a metal gun case and wear a film badge),  however, unless you leave it too long in the reactor so you get a damage to metal structure from high netron flux  .... should be fine.

Very interesting poll from my point of view, as at the moment have an option to purchase when  they transfers in (you know you have been in this game to long when you have ongoing purchase options ...) a rLL plus a IMI rr Uzi (depending on if the rail was removed or not)   ..... the other option is to purchase a rDIAS for the same ~$11K.

Thus in effect the rDIAS would be instead of a rLL and Uzi ... or required the trading of the 2nd HK sear .... (i.e. buy them all is not an option this year, even with selling pre-disposition guns  

My Previous AR15.com thread on rLL failures and the resulting concerns on wear induced cracking, just about has me thinking about passing on the rLL (this is the second full auto "M16" as already have a M16A1).  As can try to control ammo quality (use Federal XM193 and Winchester Q3131a as a backup, plus USGI / Israel M855 if wished) but not wear of the rLL ... unless the failures have been due to poor setup and flexing (vs failures from flexing of the controlled part through "normal" usage with 'non-5.56" rounds).

Primary near time frame usage for the rLL or rDIAS would be for shooting in "non-5.56" such as 7.62 by 39 (other option is just get an AK-47 or MP44) ... with the HK sears end up shooting those mostly for 9mm ... if only because of the mags being easier to load (also do not have a Talon upper, which friends do ... ).

Both can brake or need repairing.

I have been thinking about this subject and am weighing the pros and cons....IF a RDIAS were to break, how many folks out there are qualified to repair such items and are parts available, also, would it be possible to transfer the serial number from a sear that was distroyed to a new one by a manufacturer?  
How is one to know if the RDIAS in question is worn out or has tens of thousands of rounds thru it already and is old and tired?
I am leaning towards a DIAS but am still undecided.
"G"

Originally Posted By E22CAPT: I have been thinking about this subject and am weighing the pros and cons....IF a RDIAS were to break, how many folks out there are qualified to repair such items and are parts available, also, would it be possible to transfer the serial number from a sear that was distroyed to a new one by a manufacturer?

Welding is easy almost anyone with a good rep can do it for you.  Heat treating and understanding alloys is another consideration and not all welders heat treat their work. No, the serial numbers can not be transfered. You must repair the broken device.  Sear trips, pins, and springs are easy to make/get.

How is one to know if the RDIAS in question is worn out or has tens of thousands of rounds thru it already and is old and tired?

If the pin falls out easy and the holes are very egg shaped on the RDIAS it might need repaired.  The sear trips are heat treated and the pin holes do egg shape a very little but they last.

This may or may not help, but Quarterbore did a great photo/write up on this very topic...I will post the website here and tell you it is probably the most complete description on this topic I have ever found...I still think it comes down to one's preference/wallet but for me I went with a Original Colt RR...

http://www.quarterbore.com/ar15m16/index.html

Good luck!!!

Apparently (I think one of the guys posting in this thread pointed it out in another) KNS Precision has made a new part to prevent link breakage.. This could really bump up the value of a link, as fragility was the key issue after the sleect fire kits were made..

Lightning Link - BEST buy in M16's..

I know this thread has been around a while, but I wanted to toss this out... I have experience ONLY with a Broadhead DIAS, and a RR.  My main observation is that if the lower and upper are correct, with factory government-approved dimensions and pin spacings, and the DIAS + trip is made to known dimensions, it really is plug and play.  The upper rear lug I think is critical... if not correct, the DIAS won't fit, and foolishly people hack at the DIAS body rather than the lug.  DON'T!!  Modify ANYTHING you want EXCEPT the DIAS body!

The only exception to this is if the DIAS body is not correctly dimensioned.  If that is the case, I'd use an expert gunsmith or machinist to take it to spec.  On my several uppers, I've been fortunate in that the DIAS rides via friction on the upper lug and stays on it when the gun is opened.  I think it is a common mistake to think that the DIAS should stay in the lower when opened; it should hang on to the lug, IMO.  This also fixes interference between the trip and other components when reassembled.  I remember a gun for sale a while back where the guy used JB WELD to GLUE the dias into the lower!  That's nuts.

I use the DIAS far more than my RR.  At the range, I find myself more willing to let others shoot the DIAS gun rather than risk big dings and scratches to the RR.  If you were going to have just one MG, I think the DIAS is it, and if I was forced to sell, the DIAS would be the last to go!

Originally Posted By jtb33: Thanks for the replies guys.  I was leaning towards a RLL (1st), and an RDIAS (2nd).  Out of curiosity, the RLL is a thin piece of metal...  if it ever broke, can it legally be replaced?

The main body of the sear, be it a LL or RDIA, cannot be "replaced".  Technically (and legally), it must be repaired, because the registered part is the part bearing the serial number in the NFA registry.  Parts (that don't bear the serial number) can be replaced (e.g., paddle on a LL or pivot pin and non-numbered parts on a RDIAS).

LL can be repaired by simply bending the paddle back.  RDIAS are considered more durable.  You might consider finding a back issue of Machine Gun News or Small Arms Review, as the issue of LL vs. RDIAS has been extensively discussed in articles in those two publications.

I'm looking at purchasing an MG soon. Somehwere between 5 and 13 grand on it.

I really want an "M16." So I can shoot 9mm, .223, and do just about anything with it.

Does the RDIAS have to be registered in different calibers? Or if you buy one, can you use it with different uppers?

Also, can you just go out any buy a Bushy AR-15, then drop-in the RDIAS and everything works great?


My only other options were an UZI or M11/9....

Originally Posted By GuitarSlinger66: I'm looking at purchasing an MG soon. Somehwere between 5 and 13 grand on it. I really want an "M16." So I can shoot 9mm, .223, and do just about anything with it. Does the RDIAS have to be registered in different calibers? Or if you buy one, can you use it with different uppers?

That is a question I'd like to know the answer to that as well.

and while I am at it.....
I know its probably a 'Holy Grail' question, but what would be the best way to find a RR without having to pay the investor premiums of $15, $20, and even 25K?

Originally Posted By Gorilla: I know this thread has been around a while, but I wanted to toss this out... I have experience ONLY with a Broadhead DIAS, and a RR.  My main observation is that if the lower and upper are correct, with factory government-approved dimensions and pin spacings, and the DIAS + trip is made to known dimensions, it really is plug and play.  The upper rear lug I think is critical... if not correct, the DIAS won't fit, and foolishly people hack at the DIAS body rather than the lug.  DON'T!!  Modify ANYTHING you want EXCEPT the DIAS body! The only exception to this is if the DIAS body is not correctly dimensioned.  If that is the case, I'd use an expert gunsmith or machinist to take it to spec.  On my several uppers, I've been fortunate in that the DIAS rides via friction on the upper lug and stays on it when the gun is opened.  I think it is a common mistake to think that the DIAS should stay in the lower when opened; it should hang on to the lug, IMO.  This also fixes interference between the trip and other components when reassembled.  I remember a gun for sale a while back where the guy used JB WELD to GLUE the dias into the lower!  That's nuts. I use the DIAS far more than my RR.  At the range, I find myself more willing to let others shoot the DIAS gun rather than risk big dings and scratches to the RR.  If you were going to have just one MG, I think the DIAS is it, and if I was forced to sell, the DIAS would be the last to go!

I am thinking on purchasing an RDIAS soon. I have been to the dealer and the DIAS slips right in to my colt and it does hang on the upper receiver when opened. In reference to your comment above where can you get a print or description of the dimensions. I would like to check this RDIAS out before I purchase just so I will know what, if any, shimming/machining I will need to make it run.
Does anyone know of an istance when one really did just plug-and-play?