Friend at work bought a Carbon 15.  This one:


Well it has done everything wrong short of blowing up.  It won't feed right...if it does feed right it frequenlty does not extract.

The only thing not really standard on this rifle are the stock and bolt (I think).  The bolt is shorter and lighter than the normal AR-15 bolt and well...you can see the stock.

I think that the heart of the problem is this bolt.  Many different mags and ammo have been tried all with the same results.

So how about I put a regular carbine stock and a regular AR-15 bolt in her??  Anyone tried it...does the bolt fit???

The bolt/carrier assembly will interchange. The stock should....I swapped out the buffertube for a Post ban M4 style stock on my Bushmaster pistol and it worked...it was a bit tight screwing the new buffer tube into the receiver, but it went......if you use the AR stock, you have to use the AR standard bolt/carrier assembly....if you switch back to the standard stock, you have to use the factory shortened carrier/bolt and buffer assembly......they kinda go together. Keep in mind, that you will still need to take it apart the same way....push both pins and slide the upper forward, since there is no hole for the buffer retainer.....Does this make sense?

A side note...mine is the pistol lower and it is slightly different in the rear where the stock attaches. There is someone here that has done this on the rifle....hopefully he will chime in.

P.S...before you call the ATF...the pistol is now registered as an SBR.

I have 2 pistols like this and 1 early Pro Ord rifle exactly like the one you pictured....they all work great....you may have gotten a lemon.

Problem.

The plate, that goes on the collapsable CAR stock has a raised oval that fits into the oval indentation on the back of every normal AR lower.

Bushmasters carbon lower reciever back indentation for the stock is smaller, and perfectly round.

Screwed.

And ideas?

What I did was turn it around.......I then drilled a hole in the plate to match the hole in the pistol lower. The rifle doesn't have this threaded hole, but you could turn it around and put a short screw through it into a threaded "Button" that would fit the hole in the back of the receiver....Or better yet...drill and tap the hole in the plate for a larger screw that will fit in the hole better....it just need to be there so the stock doesn't rotate.....that would be easy.

Quoted: What I did was turn it around.......I then drilled a hole in the plate to match the hole in the pistol lower. The rifle doesn't have this threaded hole, but you could turn it around and put a short screw through it into a threaded "Button" that would fit the hole in the back of the receiver....Or better yet...drill and tap the hole in the plate for a larger screw that will fit in the hole better....it just need to be there so the stock doesn't rotate.....that would be easy.

Good idea.  I'm glad I thought of it.    Just kidding ya.

You've got lots of good ideas........glad I could help

?? Ammo ??

?? Magazines??

Did he properly clean and lube it (per the manual)?

If he's not using decent quality ammo in known good USGI magazines I'd try that first.  If it still doesn't work then send it to Bushmaster and have them make it right.

Quoted: ?? Ammo ?? ?? Magazines?? Did he properly clean and lube it (per the manual)? If he's not using decent quality ammo in known good USGI magazines I'd try that first.  If it still doesn't work then send it to Bushmaster and have them make it right.

Different ammo.  The factory mag, a USA mag, two seperate USGI mags

Dry bolt, clean bolt, clean lubed bolt.  Sent it back to the factory to have the pollish a bur on the left feedramp that was catching the tip of the bullets.

And after trying everything in the book, even trying to hold your mouth right when shooting it.
 FTL FTE jam jam jam jam jam.