AR-15 sheet metal and tube upper receiver

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justin22885

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so i had this idea for creating an AR-15 upper receiver, 100% compatible with all AR-15 parts except.. well, i havent added a forward assist or dust cover, but these arent necessary components

so, its made by taking a piece of 1.25" diameter steel tubing 1" inside diameter, the front is threaded to accept the barrel nut and the sides of the tube are cut out to save weight, creating "lands" that are placed in position so the raised lands on the body of the AR-15 bolt will ride on them.. this sort of skeletonized component gets pressed and welded into the sheet metal component, completing the receiver

the benefit of this?.. much cheaper construction than conventional machined aluminum uppers, not low leaves open spaces on the inside of the carrier for dirt, debris, mud, etc to get pushed into as opposed to impeding the bolt carrier, the new steel lands can be hardened and polished reducing friction of the bolt carrier riding over it, meaning less lube, fewer short strokes.. so multiple reasons why this theoretically not only makes a cheaper upper, but should have some noticeable improvements on reliability

also, the steel would be harder, and more flexible so there shouldnt be any issues with carrier tilt should a piston kit be installed with this upper, as it either wont cause enough pressure to wear the steel, or the steel will flex, not wear like aluminum

i havent put a rail on this yet, and im still working on a couple small details but its about 99% finished and when its done i'll upload the files in a 3D CAD format, but i was wondering what you guys think of it?.. the only downside is it will add about 1/2lb to the overall weight of the rifle, in my opinion this is a tiny price to pay if it creates noticeable improvements in reliability, durability, and if the open gaps actually work in giving a space for fouling and debris to go

so.. thoughts?

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yes, yes i do, but you have to admit the open spaces on the inside for debris, harder, polished rails reducing friction, no damage from carrier tilt and potentially cheaper construction are all pluses

working with sheet metal and tubing is what i primarily work with when i design something because my goal ultimately is to make things people can make in a small garage shop.. 1 piece of steel tubing, 1 simple shaped sheet metal shell and you have an AR-15 upper compatible with all AR-15 parts.. cheap, easy, small shop friendly, im also working on a simple sheet metal lower receiver too
 
you know.. i COULD still add a forward assist and dust cover to that, but is there really a reason to?
 
how are you planning to secure the sheet metal stamping in place?

i see that it is captured laterally by the receiver and the barrel nut........but what is securing it rationally?

you may want to look into adding a set screw or a detent to keep that from spinning around the action tube.....especially if you want to mount an optic to it.
 
The upper receiver is simultaneously one of the cheapest, simplest parts that yet poses the widest configuration variation of any AR part.

As to reliability this isn't 2007 with its gas piston system o the week. Everyone realizes a well maintained ar is as reliable a weapons system as a soldier much less civilian could possibly ask for

I'm not seeing a market here
 
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I can't imagine this possibly being cheaper. Also not sure the purported benefits are worth the extra 1/2 pound to me. The AR15 is already very reliable, so it is a tough sell for me to accept the certainty of the extra weight in exchange for a possible increase in reliablity that I may never be able to detect.
 
cheaper to produce, not necessarily cost savings in someone buying the component, AR-10 uppers with all the machining thats required of them would cost a lot more if they werent made in absolutely massive quantities.. all the different are "manufacturers" out there get their uppers from one of about 3 different factories producing them in such high quantities

but on a smaller scale, or something that can even be built from 0% in your garage the design i submitted above would be easier, much more low tech

if i was a factory mass producing it, id cut the inner piece out of tube steel as is designed and make the outter piece off an extrusion, also it wouldnt need to be welded, thats just an option, it can also be riveted
 
A polymer extruded or injection molded outer shell might garner some interest on weight savings. But riveted or spot welded steel just seems to run counter to every last bit of what the AR has morphed into over the past 15 yrs
 
ETA it appears to me that the optic mount will have to be steel so it can be welded to the reciever. If so this will balloon the already significant weight increase
 
the top of the receivers thick enough to drill and tap, or rivet, so the rail can be aluminum which is what i intended.. and for an M4 configured rifle itd still be a sub 7lb rifle, closer to 6.75-6.8lbs
 
What is the material thickness over the charge handle raceway? You need enough for the rivet and to be countersunk

Even if it will hold a rivet you are looking at machining a special optics rail just for this receiver

The "rugged reliability" will be a tough sell with an optics mount held on by rivets or very dainty screws with no ø depth
 
.065" thick sheet metal for the outside shell, inside is a 1.25" OD - 1" ID steel tube.. theres enough clearance above the charging handle for a flat head rivet

hmm, if this could be done with no welding, im wondering how a stainless steel version would work out
 
i kind of like the idea of a polymer outside shell........youd reduce weight and cost....and you could mold a rail integral to the shell and eliminate the need to weld or rivet.
 
.065" thick sheet metal for the outside shell, inside is a 1.25" OD - 1" ID steel tube.. theres enough clearance above the charging handle for a flat head rivet

hmm, if this could be done with no welding, im wondering how a stainless steel version would work out


I'm just not seeing the strength there. Sounds pretty flexible to me for optics much like the cheesy AK reciever optics "solutions"
 
While completely impractical, I need one. I've already got a sheet metal welded lower, this would be the perfect mate, to complete the most post apocalyptic looking AR on the block.
 
i kind of like the idea of a polymer outside shell........youd reduce weight and cost....and you could mold a rail integral to the shell and eliminate the need to weld or rivet.
its certainly possible to do that with an extrusion.. polymer outter, stainless steel inner piece.. you know, give me a moment and i can calculate the weight of that right now
 
While completely impractical, I need one. I've already got a sheet metal welded lower, this would be the perfect mate, to complete the most post apocalyptic looking AR on the block.
when im 100% finished with it i'll upload it to grabcad so you can download the 3D CAD files for it
 
with the polymer outside it would weigh about exactly the same as an aluminum upper, but you have the benefits of the harder steel rails and open spaces to work better with dirty environments
 
should keep in mind though what my primary goal is with anything i design, its not to necessarily come out with something new, or improved, but i focus on materials, tools and processes most people have available.. for example, most of us can take a piece of 1.25" steel tubing, cut out pieces of it to create the lands for the carrier to ride on, and thread the front for the barrel nut....

however most people do not have high end million machines or access to large chunks of quality aluminum billet to machine it from.. so if the upper can be made on tools many people have in their garage with materials you can generally find anywhere, and i can do the same with the lower receiver.. then gun control = defeated ;-)

my primary project though is making a rifle that can be made nearly entirely from 0%.. heres an exterior rendering of it but inside is a bolt made from 1.25x1.25" square steel, the trunnion is a piece of 1.75" round bar thats shaved/filed down in the back to fit inside the 1.75x1.25" rectangular tube receiver, the reason the front is 1.75" round is so i can fit the free-float tube off an AR-15 without modification (will weight about 7.5lbs when finished, and yes, its a .30 cal)

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