Some off you might start laughing now, but i have had this dream for a few years now to build a fighting carbine the way i like it.
I am planning to draw everything in 3d and have the parts made on a CNC machine that i own.
There are a lot of legal issues concerning manufacturing of weapons in norway, but since i will only be producing guns for testing and personal use, i belive it is possible to get permission from the police.
Why not just buy a factory made gun?
Im taking this as a challenge and for the fun of it…
I will post some drawing as soon as i begin, but i wanted to ask you guys for your opinions.
At least the first few models will have aluminium lower and upper for ease of testing.
this is some of the features i want in my gun.
Piston operated
Full lenght picatinny rail on top
AR15 barrel
AR15 bolt assembly
AR15 trigger
AR15 mags
AR15 grip
Folding stock
these are some of the features that i am more unsure of:
Reciprocating charging handle? mounted forward like the scar?
quick change barrel or just change the whole upper like the ar15?
Does anyone have any tips or comments, let me know?
If you are using the AR bolt carrier group, you should do some research before committing to a “piston” design. (The AR system does use a piston. It’s the bolt. Most AR systems we call a “piston” system add a piston and a piston rod which is way they are heavier.) It will add complexity to your rifle that isn’t needed.
I feel a reciprocating charging handle design for an AR is a step backwards. What I think would be an improvement would be a charging handle design similar to the FAL.
If using the AR barrel assembly and BCG, fabricating the upper & lower receiver from anything other than aluminum is a waste of money and will make the rifle heavier with no gain. All of the pressure and stress from firing is contained within the barrel, barrel extension and bolt. The upper receiver does nothing but hold the parts together. The lower does nothing but contain the trigger group, magazine and action spring.
I think this will be an interesting project!
PS- I missed the part about a folding stock. If this is your goal, then a piston system might make sense. This will also be your biggest challenge
I am planning to design my own bolt carrier in a square design that allowes for a higher mounted buffer spring inside the bolt, like the FN SCAR to allow a folding stock.
I was planning to use an AR15 barrel, therefore the use of an AR15 bolt group with the extractor.
I would suggest looking at a way to design the upper and carrier with rails to prevent carrier tilt. There is a system similar to your proposed design. I believe Para-Ordinance markets it. Take a look at it to see what they’ve done
To make a working AR based weapon with a folding stock and gas-tappet will require a complete redesign, something that the largest and most established firearms manufacturers in the world have not been able to pull off. I’m not saying it’s impossible, just massively labor intensive and highly unlikely to succeed.
I would recommend finding a working piston design with a collapsible stock (or design that does not require the stock to house action parts) and meld in the trigger components.
I would not recommend limiting yourself to the AR’s bolt catch or mag release, definitely weak parts of the design (ergonomically at least).
Then again, that’s essentially what the Scar and ACR are, and they aren’t all that awesome either.
Still, please be careful and conduct proper research before making plans on firing live ammo through your project.
Arcticsniper,
if I were going from total scratch and cnc the entire gun, I would look at several different models before deciding on a platform.you will have the ability to tweak design to accommodate your own. Just be careful and don’t get lost down the rabbit hole.
Good luck and keep us posted.
Charging handle should be reciprocating or not and forward mounted on the left side or interchangeable between left and right side. Mount your barrel in the method of an LMT with a split collar and two clamp bolts. Sounds like you are kind of sort of building a Robinson XCR, a rifle I like very much except for the sucky trigger. The XCR method of barrel retention though it seems inadequate to me is proven and simple. A big 'ole set screw from the bottom. I’d have put two in it. I like the XCR bolt stop as well as the ambi mag release of the LMT 7.62. If you use AR components like trigger group, bolt, bolt carrier, barrel, barrel extension and so on you will make a daunting project into one of practical scope. Good luck.
I always thought an updated AR-18/180 would be a great basic platform to improve upon (Using a milled upper and lower receiver rather than the steel stamped parts).
With some minor machining, you could use AR barrels, many lower parts and redesign the upper receiver to accept AR HGs- at least the piston-compatible pieces. And it has your square BC that might be adaptable to an ambidextrous reciprocating CH.