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9/22/2017 12:11:25 AM
Posted: 3/12/2013 4:03:50 PM EDT
A question came up on another forum, and I finally became sensible to the point that BATFE thinks the FAL lower is not a gun, whereas it insists that the AR lower is one. Why then shall we not craft a plastic gun which can be built at home without a 500 lb mill, and could marry a FAL lower, easily available from the interwebs, to an AR upper, easily orderable from the same place but which will only arrive soon after hell freezes over?

Yes, it would look quite comical with a buffer tube poking one's eye out, & a sight picture intended for a Kayan woman, but it would have several advantages:

1 - a stop gap measure for folks building their FAL rifles
2 - it could be built from parts ordered from the internet or mail order
3 - it would increase production of FAL lowers & introduce shooters to the FAL platform
4 - it would drive BATFE & anti-gun liberals crazy

Alternative materials have already been used to produce complete AR lowers, from commercial firearms makers turning out complete plastic lowers, to homemade plastic lowers and even a wooden lower (it didn't last long). This would allow thicker plastic (it doesn't have to be the same shape as an AR lower), and the stresses passed to the stock would be offloaded through the metal FAL lower, thus lowering stress on the relatively weak mounting of the buffer tube nut.

Comments?

Link Posted: 3/12/2013 5:46:09 PM EDT
It will not work. The mag attaches to the upper reciver in a FAL not the lower.
Link Posted: 3/12/2013 6:22:42 PM EDT
You would need a plastic magazine housing/interface that would provide the the front pin mount for the AR upper and the AR magazine. You would need a different style of bolt carrier. Perhaps cut in half with a recoil pin attached to it like the rat tail on the FAL carrier.
Link Posted: 3/12/2013 6:25:22 PM EDT
[Last Edit: 3/13/2013 6:54:52 PM EDT by backbencher]
True, but that's one of the parts the plastic adapter would have to supply. Along with a working magazine well, the adapter would have to house a trigger, sear, hammer, & associated springs, as well as a nut for the buffer tube to screw into. The buffer tube mount will probably be under the most stress, as that part is under constant spring tension. An AR trigger mechanism would probably work fine, but the trigger would have to have an extension to reach the FAL trigger guard.

Many of the niceties of the AR platform could be left out. The bolt hold open could be dispensed with, as could a spring operated buffer stop and punch out pins. The AR upper could even be mounted sideways or upside down in the plastic adapter, depending on the trigger adapter.

The challenge after this is to build it out of Legos ; )
Link Posted: 3/12/2013 6:35:21 PM EDT
[Last Edit: 3/12/2013 6:48:19 PM EDT by backbencher]
Canaris, I was hoping to avoid chopping any of the internals inside the upper.

Think of nesting a plastic lowered AR on top of a FAL receiver, w/ the buffer tube sticking out the back above the top of the FAL receiver. Looks silly, but should work, & drilling a working firearm out of a solid block of plastic would be easier for most folks than drilling an 80% aluminum receiver.

Please see my horrible MS paint drawing below. The black bits are standard AR & FAL bits, excepting the really long trigger. The red denotes the extent of the plastic adapter:

Link Posted: 3/12/2013 8:19:30 PM EDT
If you elevate the upper enough to allow the use of a buffer tube, then you negate the use of any of the fire control components of the FAL lower. You would have to fabricate a buffer tube support as well as new fire control parts. My original thought would probably need only the bolt carrier modified. The upper could be used as it should with an AR lower by just using another normal carrier. Again, this is just a thought experiment. God knows what other geometries and details we are glossing over.
Link Posted: 3/12/2013 8:35:01 PM EDT
Here is a photo of a AR upper with a FAL lower for illustration:

Link Posted: 3/12/2013 8:48:36 PM EDT
[Last Edit: 3/12/2013 8:52:30 PM EDT by Gamma762]
I would be vastly easier to just make a lower receiver than to engineer the "adapter" you mention. Both would have to be serial numbered as a firearm receiver if manufactured for sale.

A far more useful idea might be to design and engineer a FAL 5.56 upper.
Link Posted: 3/13/2013 6:50:57 PM EDT
Cannaris, Gamma,

Thank you for entertaining this weird idea. Given the cost of FAL fire control parts, it would seem more useful to use the relatively inexpensive AR parts which already function with the AR bolt & firing pin, & the geometries are already known. The only part to be modified would have to be an extension of the trigger. Certainly if an adapter was built, it would be the firearm, and would have to be serial numbered & a manufacturer license sought if intended for sale. My intention is not to make this for sale - my intention is to come up with a design, while not as effective as a complete AR, is certainly easier to build at home than an 80% AR lower.

Given the cost and complexity of the FAL upper receiver, it would seem that this project would certainly be a stopgap measure towards a 5.56mm FAL.

Cannaris, your idea of using the existing FAL buffer is intriguing - some AR pistol builds use a short buffer tube by chopping the bolt carrier. However, that's a near $100 part in this market, so I'm somewhat reluctant to chop one. Hence the buffer tube idea - admittedly unergonomic & introduces a weak point in the structure @ the buffer tube mount. However, the plastic mount has worked for several plastic AR lowers, and there are several ways of mounting the buffer tube since it doesn't have to support a stock. (It could be an attached wooden buffer tube that slots in place for all we care).

The economics can certainly be argued - an 80% AR receiver, if one has the proper drill press & jigs, might well work out to be cheaper. However, many folks don't have a drill press or the space the wife will allow to put one. But if one can buy a buttstock, a lower receiver, and an upper receiver, and all one needs to do is whittle & drill some holes in a piece of plastic, we will have opened home gunmaking to an ever increasing audience.

Cannaris, would you be so good to indulge us with a second picture? An AR upper a few inches above the FAL lower, in a line so that the bolt could recoil above the top edge of the FAL lower? A AR magazine in place under the AR ejection port would be nice. I understand if you don't want to take your FAL apart, @ the cost of ammo these days you don't want to have to sight that gorgeous scope back in. I would do so myself, except I lack a FAL lower & my M4 is locked away in the armory.
Link Posted: 3/14/2013 4:42:37 PM EDT
Originally Posted By backbencher:
Cannaris, Gamma,

Thank you for entertaining this weird idea. Given the cost of FAL fire control parts, it would seem more useful to use the relatively inexpensive AR parts which already function with the AR bolt & firing pin, & the geometries are already known. The only part to be modified would have to be an extension of the trigger. Certainly if an adapter was built, it would be the firearm, and would have to be serial numbered & a manufacturer license sought if intended for sale. My intention is not to make this for sale - my intention is to come up with a design, while not as effective as a complete AR, is certainly easier to build at home than an 80% AR lower.

Given the cost and complexity of the FAL upper receiver, it would seem that this project would certainly be a stopgap measure towards a 5.56mm FAL.

Cannaris, your idea of using the existing FAL buffer is intriguing - some AR pistol builds use a short buffer tube by chopping the bolt carrier. However, that's a near $100 part in this market, so I'm somewhat reluctant to chop one. Hence the buffer tube idea - admittedly unergonomic & introduces a weak point in the structure @ the buffer tube mount. However, the plastic mount has worked for several plastic AR lowers, and there are several ways of mounting the buffer tube since it doesn't have to support a stock. (It could be an attached wooden buffer tube that slots in place for all we care).

The economics can certainly be argued - an 80% AR receiver, if one has the proper drill press & jigs, might well work out to be cheaper. However, many folks don't have a drill press or the space the wife will allow to put one. But if one can buy a buttstock, a lower receiver, and an upper receiver, and all one needs to do is whittle & drill some holes in a piece of plastic, we will have opened home gunmaking to an ever increasing audience.

Cannaris, would you be so good to indulge us with a second picture? An AR upper a few inches above the FAL lower, in a line so that the bolt could recoil above the top edge of the FAL lower? A AR magazine in place under the AR ejection port would be nice. I understand if you don't want to take your FAL apart, @ the cost of ammo these days you don't want to have to sight that gorgeous scope back in. I would do so myself, except I lack a FAL lower & my M4 is locked away in the armory.


How would the hammer reach the firing pin if you put the upper so high its buffer would go over the rear sight assembly on the fal lower? Any way to kitbash them together would take more effort than it would be worth id imagine as you could probably mill a piece of aluminium into a regular lower about eas easily as make a adapter and it would be more ergonomic.
Link Posted: 3/14/2013 4:54:18 PM EDT
[Last Edit: 3/14/2013 4:55:51 PM EDT by Pro2ndAm]
Are there many rifles that are based on that concept that takes AR mags? FN FNC, Beretta AR-70, Daewoo?
Link Posted: 3/14/2013 6:01:00 PM EDT
Kali, if you check my bad sketch above, it's the trigger that gets the extension, not the hammer. The buffer tube would go over the top of the FAL receiver, but the rear sight of the FAL would not be needed; AR sighting sytems would be used. One way to help the ergonomics, which I realized last night, would be to tilt the FAL lower so that the rear of the stock more nearly reaches the plane of the barrel.

80% AR receivers are out there & folks can drill them on a drill press. However, many folks are reluctant to risk making a mistake on a $100 piece of aluminum; I want folks to be able to make a mistake on a $15 piece of plastic.

Pro2Am, the advantage to this concept is that it not only takes AR mags, but AR uppers, buffers, & trigger components. The objective is not a proper AR lower, but a substitute-standard lower that almost anyone can build on their kitchen table.
Link Posted: 3/14/2013 6:19:46 PM EDT


Version .1, w/ tilted FAL lower, to lower sight line relative to the stock.
Link Posted: 3/15/2013 6:17:45 PM EDT


All I have to say.
Link Posted: 3/15/2013 11:09:08 PM EDT
Originally Posted By backbencher:
Kali, if you check my bad sketch above, it's the trigger that gets the extension, not the hammer. The buffer tube would go over the top of the FAL receiver, but the rear sight of the FAL would not be needed; AR sighting sytems would be used. One way to help the ergonomics, which I realized last night, would be to tilt the FAL lower so that the rear of the stock more nearly reaches the plane of the barrel.

80% AR receivers are out there & folks can drill them on a drill press. However, many folks are reluctant to risk making a mistake on a $100 piece of aluminum; I want folks to be able to make a mistake on a $15 piece of plastic.

Pro2Am, the advantage to this concept is that it not only takes AR mags, but AR uppers, buffers, & trigger components. The objective is not a proper AR lower, but a substitute-standard lower that almost anyone can build on their kitchen table.


And what is the extended trigger connecting to? You realize all the fire control groups including the hammer are in the fal lower and not a ar upper right? Also where does the buffer tube screw in? that screws into a ar lower not the upper as well where would it interface with a fal lower?

Also I don't care about the rear sight my point is if you have the ar reciever high enough up so that a buffer tube could go over the rear of the FAL lower which means that hump with the rear sight included there is no way in hell that the FAL hammer would reach the firing pin. If you can't see the problem with this no offense but I don't think you fully understand the mechanics of what happens when the trigger is pulled that makes the gun go bang.

In the end it would be a God awful gun as far as ergonomics so bad that id rather carry a 30-30 lever gun into a firefight, plus to make it viable in any sense would require a lot of machining and screwing up perfectly good FAL parts. The only way I could see you even getting the AR upper low enough for a FAL hammer to work and have a conventional bolt carrier and buffer would be to machine off the entire rear hump of the FAL receiver.

Also if this is about something easily producible for people in ban states or something where are they even getting magazines and why risk jail for a clunky monstrosity?


Link Posted: 3/16/2013 7:15:34 AM EDT
Kali, to answer your questions in order:

1 - The extended trigger is connecting to otherwise standard semi-auto AR fire control parts, in standard AR geometry, in the correct place below the AR upper, mounted inside an appropriate spot in the plastic adapter.

2 - Yes, and I don't see an easy way to adapt FAL fire control parts to hit an AR firing pin, and they look a bit more expensive than the equivalent AR parts, hence my plan to use AR parts high up in the plastic adapter.

3 - A standard AR buffer tube would either screw into a metal nut embedded into the plastic upper above the highest part of the FAL lower, or be held in place by an extension of the plastic adapter which encloses the standard buffer tube; the metal buffer tube would then be held in place by the pressure of the buffer spring. An alternative to a standard AR buffer tube would be to either make one from wood (shall we call it the Witch?) and instead of screwing into the plastic, simply slot it in place. A second alternative would be to make the buffer tube part of the plastic adapter itself, which would require considerable reinforcement.

4 - I envision the buffer tube would have to sit above the highest part of the FAL lower. Not very ergonomic, but the alternative is to chop the AR bolt carrier, a $100 part, in order to use the FAL buffer spring, which might not work, or drill holes in the FAL receiver, a $100 part, to poke the buffer tube through.

5 - You're quite correct, I don't see any way to use the FAL fire control parts; hence the use of cheap AR parts w/ a trigger extension.

6 - Indeed, the ergonomics would be worse than the 1960 ergonomics of the AR; this certainly isn't intended to take to a firefight. It would certainly make an interesting range gun, & might be reasonably accurate, though not as accurate as a proper AR lower or FAL upper.

7 - The whole aim of the design is to avoid machining any metal, and to avoid screwing up perfectly good FAL parts. If I've given you the impression that I wanted to whittle on good & expensive FAL parts I've utterly failed in my MS Paint sketches.

8 - I think you are on track w/ the idea that to use FAL fire control parts the rear of the FAL receiver would have to be removed, or at least drilled for the AR buffer tube; that might turn out to be a good hybrid and work well, but I will leave others to whittle on their FAL receivers - I am simply trying to figure out the dimensions & internals of a plastic adapter that would mate the two receivers without cutting expensive metal parts.

9 - Depending on the laws in ban states, they might be able to use such a design, they might not. This is not intended specifically for shooters in ban states; it's an attempt to exploit a loophole created by the BATFE in their rulemaking, to illustrate how arbitrary that rulemaking is, to open up home gun making to an audience that doesn't have metal working tools or the money to cut on expensive 80% lowers, and to have fun tweaking the noses of those that would disarm us. Building a plastic adapter, which would be the "firearm", is no more illegal than drilling an 80% AR lower or cutting rails on an 80% 1911 frame, & risks no gaol time in free states in the US. You're building a firearm, for personal use. It's out of plastic, but a plastic lower receiver doesn't violate any laws - there are several plastic AR lowers available.
Link Posted: 3/16/2013 12:48:47 PM EDT
Originally Posted By backbencher:
Kali, to answer your questions in order:

1 - The extended trigger is connecting to otherwise standard semi-auto AR fire control parts, in standard AR geometry, in the correct place below the AR upper, mounted inside an appropriate spot in the plastic adapter.

2 - Yes, and I don't see an easy way to adapt FAL fire control parts to hit an AR firing pin, and they look a bit more expensive than the equivalent AR parts, hence my plan to use AR parts high up in the plastic adapter.

3 - A standard AR buffer tube would either screw into a metal nut embedded into the plastic upper above the highest part of the FAL lower, or be held in place by an extension of the plastic adapter which encloses the standard buffer tube; the metal buffer tube would then be held in place by the pressure of the buffer spring. An alternative to a standard AR buffer tube would be to either make one from wood (shall we call it the Witch?) and instead of screwing into the plastic, simply slot it in place. A second alternative would be to make the buffer tube part of the plastic adapter itself, which would require considerable reinforcement.

4 - I envision the buffer tube would have to sit above the highest part of the FAL lower. Not very ergonomic, but the alternative is to chop the AR bolt carrier, a $100 part, in order to use the FAL buffer spring, which might not work, or drill holes in the FAL receiver, a $100 part, to poke the buffer tube through.

5 - You're quite correct, I don't see any way to use the FAL fire control parts; hence the use of cheap AR parts w/ a trigger extension.

6 - Indeed, the ergonomics would be worse than the 1960 ergonomics of the AR; this certainly isn't intended to take to a firefight. It would certainly make an interesting range gun, & might be reasonably accurate, though not as accurate as a proper AR lower or FAL upper.

7 - The whole aim of the design is to avoid machining any metal, and to avoid screwing up perfectly good FAL parts. If I've given you the impression that I wanted to whittle on good & expensive FAL parts I've utterly failed in my MS Paint sketches.

8 - I think you are on track w/ the idea that to use FAL fire control parts the rear of the FAL receiver would have to be removed, or at least drilled for the AR buffer tube; that might turn out to be a good hybrid and work well, but I will leave others to whittle on their FAL receivers - I am simply trying to figure out the dimensions & internals of a plastic adapter that would mate the two receivers without cutting expensive metal parts.

9 - Depending on the laws in ban states, they might be able to use such a design, they might not. This is not intended specifically for shooters in ban states; it's an attempt to exploit a loophole created by the BATFE in their rulemaking, to illustrate how arbitrary that rulemaking is, to open up home gun making to an audience that doesn't have metal working tools or the money to cut on expensive 80% lowers, and to have fun tweaking the noses of those that would disarm us. Building a plastic adapter, which would be the "firearm", is no more illegal than drilling an 80% AR lower or cutting rails on an 80% 1911 frame, & risks no gaol time in free states in the US. You're building a firearm, for personal use. It's out of plastic, but a plastic lower receiver doesn't violate any laws - there are several plastic AR lowers available.


Makes a lot more sense when you fully explain it. With the short explanations and ms paint sketches initially I thought maybe you were just a kid brainstorming .

Still seems like way too much work and spending money on good parts that could make non frankenstein monstrosities otherwise. All you would need are the associated stripped recievers of each half weapon and put something better together. Pretty much every serious firearms enthusiast knows how arbitrary the ATF's rules are I don't think this would change anyone's mind as the anti's are so far off in lala land that they watch 80's action movies to get all their information about firearms. Hell they think we can buy bazookas and gernades at gunshows.... But to each his own I guess, good luck with it.

One last thing I think a hk,ptr, cetme lower would be a hell of a lot easier to work with for your idea since you are going to have to make provisions for the ar mag well buffer tube etc you could make a plastic frame holding those parts where the hk lower clips in. fire countrol still wouldn't work because the rear lug where the crosspin goes into the ar upper hits the trigger group. I'll post a picture to clarify in a second still think its overly complex though
Link Posted: 3/16/2013 12:56:46 PM EDT
Crappy cell phone pic as promised.

Link Posted: 3/16/2013 1:22:12 PM EDT
Many thanks, Kali, and I will have to read up on the CETME & HK G3 lowers. My idea for use of the FAL lower was to allow the plastic adapter something solid to compress against, thus adding some strength to the otherwise plastic lower. The ergonomics just aren't very good. There have been some thumbhole AR stocks in the past, but Bell & Carlson has discontinued theirs, probably b/c California banned thumbhole AR stocks. I'm still looking for something else suitable, as a thumbhole stock would solve the ergonomics issue, as well as reinforce the plastic lower. We'll see - I may be playing w/ Legos a lot over the next year : )

Nice pic of the toes.
Link Posted: 3/19/2013 1:22:34 PM EDT
What about a berreta AR70 trigger housing, I dont know how it would line up but you would be starting with a mag well and everything. The only difficult thing would be the recoil/ buffer tube, that being there isnt one on the ar-70

just throwing it out there
Link Posted: 3/19/2013 11:50:55 PM EDT
Originally Posted By jakjak824:
What about a berreta AR70 trigger housing, I dont know how it would line up but you would be starting with a mag well and everything. The only difficult thing would be the recoil/ buffer tube, that being there isnt one on the ar-70

just throwing it out there


jakjak, it all hinges on whether the lower of the AR-70 is the registered part or not. Did BATFE screw it up so badly that the "gonne" of the AR-70 is the upper?
Link Posted: 3/20/2013 12:10:38 PM EDT
[Last Edit: 3/20/2013 12:14:16 PM EDT by jakjak824]
Pretty sure the upper o the AR 70 is the registered piece, U can by the "trigger housing" without an ffl.

http://www.gunpartscorp.com/Manufacturers/Beretta-33152/Rifles-35389/AR-70-38547.htm?results=All

it is #51
Link Posted: 3/20/2013 4:38:12 PM EDT
That's just crazy stupid by the BATFE, and it's not that expensive either. We still have the problem of the buffer tube, however; that might be solved by a thumbhole stock, and it would be amusing if the AR-70 SA hammer & trigger could be made to work. We would have to saw off the rear of the lower, but I don't feel like I'm ruining someone's expensive build by doing so - from reading last night on AR-70 builds, apparently AR-70 upper builds are not that easy.

We would probably end up w/ the plastic buffer tube adapter that's glued to the thumbhole stock would be the actual "gonne", and the AR-15 upper & AR-70 lower are just parts. God bless the BATFE.

Well, off to start a thread in the Beretta Forum.

Link Posted: 3/31/2013 5:32:31 PM EDT
Any ideas as to what I should use for a horizontal datum?



Most of the holes are easily measured to the top of the receiver. The rear of the receiver is on a slight angle, and the front of it has a lovely curve.

Went & bought a Beretta AR-70 lower from Numrich. Easy to measure the holes, & measure to the top rail; but not so easy to take measurements front to back.
Link Posted: 4/21/2013 9:02:03 AM EDT
[Last Edit: 4/21/2013 9:18:48 AM EDT by donmopar]
In an effort to make it cheaper you are going to make a part that is more complex than the existing ar 80%. Why would it be cheaper. Your other thought is you would be able to get around the law but instead all you would be making is an 80% that needs to be completed or an actual receiver (registered part) so there is again no gain.
Why not try to make an ar 80% that is cheaper. Why not go to the place that makes plastic lowers and see if they could modify there mold process and make an 80%. If complete plastic lowers w/lpk are $100 maybe they could be the same for an 80%. The other thought would be a printed lower but getting the plastic lpk would be a big savings.
With that said why not just get an aluminium %80 for the $100 and go to one of the places that allow you to push a button on a cnc and mill the rest out for around $50.
In the long run we are looking at saving less than $100 by making an abortion of a gun. While still spending several hundred on upper parts.
Link Posted: 4/22/2013 11:51:49 AM EDT
And your objections led me here:

http://www.ar15.com/forums/t_3_4/607340_Legos_.html
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