well, in the pictures below, my plans are revealed. but, first, let us get something squared away. yes, i am building an ar-15 sized gun out of wood, and yes it is a laminated structure, but, it is not in the strictest of sense of the word, "plywood." plywood, even good grade plywood, can have some stuff in it, and even voids, faulty laminates, and the like. no big deal, it's plenty strong for what it does, ... , actually, hell for stout.
the "lams" in my little wood gun is straight grained, no flaws, good walnut sawn "boards," and not stripped veneers. it is very very strong, and quite dense, much like the stuff ruger, savage, remington and winchester use for their laminated stocks, not to mention boyd's, a very large after market stock maker. it is my belief that these people could stick a plywood blank into a cnc-controlled mill, and have it kick out a plywood lower receiver looking identical to an aluminum lower, and have it been fully as strong.
so, why did i bother? well, that's a very good question.
and, the very good answer is because i have an uncontrolled curiosity, and i wanted to see if i could cram an ar-10 sized magazine, made for .308 winchester rounds, into an ar receiver sized for the ar-15 sized magazine, ... , in short, a full sized .308 magazine into an ar-15 receiver.
well? the answer is, yes you can. quite easily, as a matter of fact.
the proof is right below.--
caption: there is my dial caliper, opened to nearly 6.300", which is as far as it will go. check the dial, you should be able to read it, if you click the picture and enlarge it. the paper below is an outline of the receiver when done, with important dimensions and pin and safety lever center locations marked on it. (hint: you can get blueprints for this off the net, which i've done. you can painstakingly measure the locations on the receiver for hours, not getting the same result twice. or, you can carefully tape a piece of paper on a receiver, and rub vigorously with a lead pencil over the locations, and make an outline, which i finally resorted to. hint: the latter works best, with the blueprints to verify.)
if you look at the above paper, you will see that center to center for the captive pins on my tracing is 6.375", which is also the blueprint numerical value for the distance between take down pins on a standard spec ar-15 receiver.
if you look at the "inside left" steel cladding, it is leaning on an ar-10 magpul magazine. all this is just behind the little paper, with the other standard dimension for the ar-15 receiver.
o.k., back to the narrative. well, how can this be, you say, the ar-10 magazine is so very much bigger than an ar-15 magazine, to which i say, yes, it is. so, you say, you cannot do this, to which i say, oh, yes, i can indeed do this.
how, you ask. by using my noodle, i say.
and, i must observe, this isn't all for free.
ordinarily, the space between the cavity for the magazine and the cavity for the trigger group in an ar-15 is taken up by space devoted to the machining of holes of various shapes for the magazine release, and the bolt stop. to put the matter as simply as possible, i simply used this space to extend the magazine well, and make it long enough, at 2.960" to accommodate an ar-10 magazine. in terms of length, this is simple as pie, and all you have to do is abandon the normal machining used for the mag release and the bolt stop.
in my estimation, this is no biggie. the rooskies did not use a bolt stop/hold open on the ak-47 (or ak-74, to my knowledge) for well over 60 years, and that weapon killed people in droves without apparent limitation. so much for the need for a bolt stop.
caption: the metal cladding, lying atop the wood laminate. the metal goes out a little past the body of the wood, ... , when i have finished placing the magazine well, i will mortise its cavity, using a mortising machine and mortising bits. the drill square holes, doncha know. actually, the bit drills round holes, and it is enclosed inside a "hollow" four sided chisel, which follows along and makes the extended square cut. pretty clever, what?
if the mag goes to far to the front, i will simply take the rest of the wood away, and put a steel or aluminum plug between the cladding walls, and use that as the front of the magazine well. we'll secure it with small bolts and nuts, i am thinking right now, unless one of you has a better idea.
as to the magazine release, i think i may be able to shoehorn it in, in its current form, if i get lucky. if not, i will simply substitute something that i have in mind, and which i am not going to reveal to you. i am that sort, you know.
but, i should be able to squeeze that in, if i want to. the trouble is, i am not so overly enamored of the ar-15/10 magazine release, viewing it as sort of overly complicated in most respects. i always just liked the simple latch on the side of the magazine as used by the froggies in their semi auto they developed prior to wwii, but never got into service. besides being butt ugly, i suspect that it was a pretty good rifle. i had a friend who owned one, and i shot it, and it seemed to work pretty well.
it was, however, so ugly as to be offensive to american sensibilities. both of them, even.
o.k., you say, because you've been paying attention, you've got the length of the magazine covered, but how about the width, because an ar-10 mag well is 1.090" wide, and an ar-15's isn't. o.k., you've got me on that one, ... , but, no you don't. i made the silly-assed lower out of wood, and i made it plenty wide enough to accommodate an ar-10 magazine, as made by magpul.
caption: this is not the finished laminate plug, (as i have take to calling it), but i am going to use it for its pedagogical virtue in this post.
and, what is its pedagogical virtue? well, as opposed to most pictures i take it is in focus, and the color rendition is pretty good. now, look at either side of the plug, and the outside layer of walnut there. about mid-way through that layer, (now covered by an actual layer of birch modeling plywood, and soon to be covered by a stainless steel cladding), is just where the outside of the magpul magazine will rest.
in other words, from side to side, it is 1.090" to the mid-point of those walnut layers. so, the nice plastic stuff magpul makes their mags out of, will slide against some very durable walnut, and it should all be just slick as a whistle.
am i worried the wood will wear? nope, i am not. i am from a generation in which we quite commonly used wood as bearing surfaces in heavy duty machinery, and it wore just fine. for years. and was as simple as i am to replace.
marvelous stuff, wood. i am actually thinking of using it to either reinforce the front of the magazine well, and just epoxy more in place as a wear & structural surface. hey, it's been done.
well, that is it.
i am building an ar-15 lower receiver out of laminated wood to accommodate an ar-10 sized magazine, so that i can increased the overall loaded length of my "jj's brit" cartridge, so that i can put more powder in it, and shoot 120-130 grains bullets to around 2650 feet per second from an 18.5" barrel. neat, huh?
why am i doing that? because the rest of the american firearms industry has not thought of doing so in the last 60 odd years, that's why. i think gun designers are the biggest bunch of idiot do nothings who ever got paid far more than they are worth, ... , to say they lack imagination is kind of putting it mildly. the design parameters of the ar-15 got established years ago, and they have remained absolutely unchanged since, ... , no one has the gumption to mess with the established shibboleth, i guess.
in the meantime, the japanese, germans, english, americans and even the froggies have completely digitized the automobile, elevated the pop up toaster to its present zenith, and put men on the moon.
yet, the ar-15 remains unchanged, except for plastic furniture. there, i got that off my chest.
i'll keep you posted.
john jay @ 12.12.2013
p.s. hey, what about the nut at the end of the receiver? whatcha doing about that? gotcha covered jack, i'll tell you about that in a bit. but, the solution will be simple. after all, i thought of it.
last word on the subject, well, a picture as a matter of fact.--
caption: additional layer of wood, culminating layer of stainless steel cladding. you think that ain't gonna be strong? laughing. that will make an extremely sturdy mag well, and probably stronger than a present ar-10, or an ak-47 for that matter.
i think you gotta like the whole concept. i just don't know why boyd's doesn't simply build a lower out of their laminated material. it's hell for stout.
JJ -
Your engineering feat of manufacturing a plywood gun comes just in time. Congress has just renewed the ban on 3D printers production of plastic firearms by law abiding citizens for another period of time. In what calibers will these little beauties be available?
Posted by: Citizen Patriot | December 12, 2013 at 06:52 PM
citizen patriot:
it's not so much a plywood gun as it is a sheet metal gun. for years i've been cogitating on how to make an ar-15 the same way the rooskies make the sheet metal ak's -- sakes alive, you get up an properly automated factory w/ continuous sheet metal rolls getting stamped by robots, bent by robots, ... , etc., and you could make a gizzillion of the damned things.
so, my gun is just sheet metal without any getting bent, and the sheet metal spaced out by "plywood," though i think "laminate" far nicer a term. more refined, ain't it?
basically, all you need on these assault rifles are holes to put pins to locate and hang stuff, and they just work. trigger pin, safety pin, & hammer pin, and you got yourself an action for a semi-auto, a full auto, or a burst-fire auto, all off the same geometry.
that's the genius of the ar-15/16 platform, the fire control mechanism. it's really kind of idiot proof, you put the pins in the right geometry.
the upper receiver is all right. and, all the problems they've had are caused by people doing things w/ the platform that were never contemplated when the gun was designed -- it's a damn miracle the thing works at all, given all the changes to "mission," let alone works as well as it does w/ minimum tweaking.
by contrast, the ak-47 has shot one bullet/cartridge that i know of, the 123 grain spitzer at 2350 fps at the muzzle. one load.
contrast that w/ the ar-15, which has shot so many rounds out of so many different barrel lengths that its hard to remember them all -- and, it just works, more or less.
hell, build the upper out of steel, like they ought to, and i don't want it would take to stop it.
besides a not very good magazine retention design. that's why i am not stuck on getting the old mechanism in this rifle, because it is the one true design weakness w/ the gun.
have a good day.
john
p.s. this was is being built in "jj's brit," overall length 2.7" or so, as compared to 2.260". no other changes besides bullet seating depth. more speed, same pressure. same speed, less pressure.
that trade off being explored.
Posted by: john jay | December 12, 2013 at 09:35 PM
Ah, now I can see it in my minds eye, and it looks beautiful.
Perhaps when I'm finished making Christmas gifts (of wood) for the kids I'll have another project to fill my spare time.
Posted by: rightwingterrorist | December 13, 2013 at 06:22 AM
right wing:
the beauty of the wood gun is that it can be readily adaptable to whatever caliber upper you want to put on it, and whatever magazine you wish to stick in the magazine well.
really, if i can get my "jj's brit" (long version) to feed out of a ar-10 magazine (.308 win. length), i am at something of a loss about what you couldn't conjure up.
sub-machine gun, uzi mags?
who knows?
john jay
Posted by: john jay | December 15, 2013 at 04:38 PM