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 Bulpup lower that will accept AR 15 uppers?
JRCmx  [Member]
4/19/2011 10:41:37 AM
someone must have put some thought into building a bulpup lower that will accept AR uppers. Can it be done and work right?
AJ_Dual  [Team Member]
4/19/2011 10:55:23 AM
I could swear I've seen someone who rigged up a prototype somewhere.

However, it was really ungainly and not something that would ever be a production item. The main problem is the buffer tube which pretty much mandates a traditional layout. So you'd have to go with one of the piston or bufferless pistol style uppers that does not need the recoil spring in the buffer tube to operate, and instead has it tucked up in the top of the receiver.

Or they just stick with the buffer tube, and OAL and LOP of the AR bullpup barely saves you any length at all.



RDTCU  [Team Member]
4/19/2011 10:58:47 AM
Thought about doing it on one of my pistols an an SBR, but then i decided to just go with a folding stock...

But yeah, a standard AR upper won't really work without a buffer tube of some sort...
Dawg180  [Team Member]
4/19/2011 1:00:03 PM
The buffer tube and spring and the recoil stroke of the carrier makes a big mess of things. Ace riflestocks was working on it before they were bought out.

The other issue is you somehow have to get a grip and trigger underneath the barrel.

Truth be told I did some engineering and design work on this about 2 years ago and was pretty far along, but ultimately I came to the conclusion that it was easier to design a bullpup from scratch than to try an adapt an existing conventional AR layout to bullpup configuration.

Sven

Onslaught  [Team Member]
4/19/2011 1:45:50 PM
Originally Posted By Dawg180:
The buffer tube and spring and the recoil stroke of the carrier makes a big mess of things. Ace riflestocks was working on it before they were bought out.

The other issue is you somehow have to get a grip and trigger underneath the barrel.

Truth be told I did some engineering and design work on this about 2 years ago and was pretty far along, but ultimately I came to the conclusion that it was easier to design a bullpup from scratch than to try an adapt an existing conventional AR layout to bullpup configuration.

Sven



A Bullpup, designed from scratch, BUT one that could use existing AR parts (FCG, bolt, BARRELS) would be great for commonality, availability, and affordability of parts.
RDTCU  [Team Member]
4/19/2011 2:05:30 PM
A bullpup using an AR15 bolt would only let you shorten it by about 3-4 inches max, and that's without a buffer....


I'm building THIS:





gypsieshooter  [Member]
4/19/2011 7:51:15 PM
You could use a Para Ordnance upper. The pistol grip and trigger could be mounted on the free float tube. But by the time you designed the lower you could of made something totaly unique and new. Like above.
Onslaught  [Team Member]
4/19/2011 10:51:58 PM


I just meant the bolt, not the bolt plus carrier.

BUILD FASTER MAN! I want to see this thing RUN!
MadDogDan  [Team Member]
4/20/2011 9:42:23 AM
Now that there are piston uppers that do not use traditional buffer tubes like the AR's made by Para Ordnance and Rock River, it will be easier to design a bullpup lower for an AR upper.

MadDog