I came away with this rifle after a trade for one of my pistols. I know that most people dont have much good to say about the carbon 15 line of rifles but even so I still think i came out ahead in the trade since I only hasd approx. $400 in the pistol I traded for it.

Anyway, I would like some info on the rifle. First I need to know if all of the parts on the rifle will transfer over to a standard mil-spec upper and lower. I plan on using this rifle as a base to build up from, so I'm hoping that all of the parts are interchangable. I want to swap in a standard upper and lower at some point. I have a S&W M&P 15 that I swapped parts out on and everything from each rifle would switch over to the other (bolt, charging handle, etc.)

Second, can anyone tell me what model exactly this rifle is? It doesnt give a specific model on the gun, just says carbon 15. I've looked all over the net trying to find another like it but im not having any luck. Its a 20in barrel, with the dust cover and forward assist on the upper. I can find other carbon 15 rifles, but none of them seem to have these features.

Heres a few pics for you guys to study.

Perhaps it's not a Bushmaster upper?

I thought about that. Maybe its not, but I couldnt find any other brand that makes a polymer rifle.

I've seen a couple carbon fiber type uppers over the years. Didn't Vulcan make one back when?

 

DONT DO IT!!!!

The barrel markings look just like my Bushmasters.  The upper looks a little different.  I didn't know Bushy did a rifle on the Carbon 15 lower.  I thought they only did the AR pistols.  Sorry I can't be of more help.

I don't know much about Carbon 15s, but it looks like it would be easy to buy a stripped aluminum upper and lower and transfer all the parts over.  

ETA: Call Bushmaster and have them run the Serial # and see if that is an original configuration.  The only Carbon 15s I've seen are the pistols and retard abortion carbines.

Yes, all the parts should transfer over....go buy an aluminum upper and lower of your choosing.

Now, go run and do that like soon or right now....trust me

Thats what im thinking. I dont so much mind the lower being polymer, just not the upper. I'm gonna order an upper from bravo company and we'll see how it goes.

Look at the link above for pics of the carbon 15, upper looks identical.

Yep, thats the one.

I just ordered a new upper reciever from BCM and I'm going to the shop tomorrow to see about getting a lower for it too.

I'm not too worried about the lower right now, its the upper that concerns me. I dont see the lower being under enough stress to cause a break.

Update:

I ordered standard upper and lower recievers for this gun. The upper came in yesterday and the lower is still on the way.

Everything from the carbon upper will fit on the metal upper except for the barrel nut. The threads on the polymer upper are slightly thicker than the metal upper.  So anyone wanting to replace your carbon 15 upper with an aluminium upper needs to get a standard barrel nut.

I'll update this again next week when I get the lower in. Hopefully all the lower parts will switch over without any issues.

Carbon 15 upper:


BCM standard upper:

It will be cool to see how this ends up. Thanks for keeping us updated.

Franken gun.  They used Carbon 15 receivers and otherwise standard A2/4 parts.  Perhaps they saved 4 to 6 ounces depending on what internals they used.  What a waste of time.

But a nice lightweight carbine could be made from it, just keep the rate of fire low to keep from over heating the upper.  Barrel heat into the upper threads could cause failure.  But as a purely hunting carbine it would be fine.  How many round do you fire when huntingm anyway?

I want this to be a backup to my other ar for classes, matches, etc. I dont want to have to deal with the possibility of breaking a plastic reciever.

I agree that using a polymer frame was a waste of time, since I can't tell any weight difference from the polymer upper and the new standard aluminium upper I bought to replace it. Maybe the lower will be lighter, but I doubt it.

Some lowers were noticeably lighter and worth the effort IMO. The CavArms stuff is great, but they don't make it any longer. There was a significant weight reduction in those lower halves without sacrificing strength.

 

Model AZ-C15R20 - Bushmaster Carbon-15 model semi-auto rifle(Prod.# AZ-C15R20) in 5.56 (.223)Cal. This rifle features a 20 inch hvy. bbl., matte black finish carbon fibre upper and lower rcv., flattop upper rcv. with detachable carry handle, and fixed A2 type buttstock.

Good post. that sucks

New update:

Finally got the upper and lower in. Everything went together without any issues just like id planned.

I did find out that the rear takedown pin is longer on the carbon lower, so I had to order a standard rear takedown pin.

So for anyone thinking about doing this swap you need to order these parts:
1. Barrel nut. The carbon reciever threads are thicker so the carbon barrel nut wont fit on a standard reciever, its too big.
2. Rear takedown pin. The carbon reciever is thicker at the rear takedown pin so its way too long for a standard reciever.
3. Trigger guard bar. I didnt even think about this one until today. The carbon lower has the trigger guard is molded with the reciever.

Heres a few pics of the lowers: You can see the longer takedown pin in the first pic. Its on the aluminium upper

Thanks for the update. It's interesting to see the two of them side by side.

Rifle is finished.

Got all the parts in today and finished it all up.

Heres a quick recap: Got the rifle on a trade for a pistol. Had about $400 in the pistol. I didnt like the polymer recievers on the gun, so I ordered standard recievers for it. Everything from the polymer reciever fit on the standard ones except the barrel nut, rear takedown pin and trigger guard.

Now I have a nice rifle for around $600. Only other thing I want to do is get another bolt for it. The bushmaster bolt doesnt appear to be MP tested, its not stamped on the bolt.



The flash got that at a weird angle I guess. Theres a little difference in color from the upper to lower, but nothing like this. Upper is closer to a satin black, where the lower is very flat.




Heres what I have in the rifle:
Bushmaster 20" standard chrome lined barrel
Spikes tactical lower reciever
BCM flat top upper reciever
Bushmaster BCG
Bushmaster lower parts
Magpul MOE grip and Magpul polymer trigger guard.
CSAT rear sight

CSAT rear sight

how do you like it?

I love it.

It takes some getting used to, but once comfortable with it you have a sight that will go from point blank (literally) out to 300 yards without having to change any settings. I've been taught when running CQB situations with a standard sight zeroed at 100 yards to use the front sight just over the top of the ring to compensate for sight offset. The CSAT sight uses that principal, but gives you a way to do that very precisely.

Its designed to be zeroed at 7yards using the top notch. Its just like a pistol sight, line up the front sight post level with the top of the notch. A zero at 7 will get you very close at 100 using the lower sight hole. Once you have the lower sight set at 100 then you're good. I sight mine to hit where the front sight cuts. I like to have my bullet impact wherever the top of the sight is touching

Anything 25 yards and in use the top sight notch, anything further use the bottom sight. Out to 200, you dont have enough of a drop to notice. Out to 300, theres maybe a 5-6in drop, still not even enough to notice for a combat sight.