So, background of the rifle is it's an LWRC m6a2 with about 400 rounds through it. Those rounds had all been xm855 or whatever the green tipped, armor piercing army surplus ammo is called exactly. It's been properly maintained and lubed (w/ CLP breakfree on the buffer spring, and TW25 lube on BCG and everything important). With these 400 rounds shot previously, I experienced the exact same FTE issue, only much much less frequently (once ever other mag or so, instead of every other round.)

Went to the range yesterday, and wasn't able to use the ammo I was used to using because it's a fire hazard and also would destroy the ranges targets, so I used some 25 year old white box (Federal I think, see pic) ammo. How it all went down was I shot about 10 rounds through my rifle and everything worked perfectly. Began shooting the next mag and and every round possible was an FTE. This happened with all 5 of my pmags (mags arent the issue, the one that worked at first didn't the second time around). The round in the magazine would get smashed into the one still in the chamber, causing the bullet to get shoved back into the casing.
http://img805.imageshack.us/img805/4606/imageknm.jpg
Upon closer inspection of the case left in the chamber, the actual FTE, you can see the brass got ripped around where the extractor touches it.
http://img85.imageshack.us/img85/7994/imageunn.jpg
Only thing I can think is that the brass isn't very strong, it's 25 some years old and comes in a box that looks like this http://img225.imageshack.us/img225/5196/imageskp.jpg
Actual Jam:
http://img441.imageshack.us/img441/5052/photo2t.png
Got pretty frustrated after shooting 30 rounds with every one being an FTE, decided to go to the range store and buy some other ammo. Got box of 20 rounds of PMC .223 (not 5.56mm), and went back to shooting. Went all 20 rounds and not only cycled perfectly, actually felt good to shoot. Same mags and everything, hand't cleaned rifle between then, no re-lubing or anything. So rifle is capable of functioning well, so it's either the ammo being higher quality, different caliber, or something to do with the extractor (I looked at the extractor when I got home, looks perfectly fine). After removing the extractor, I looked inside the bolt and saw this
http://img827.imageshack.us/img827/3559/imagezna.jpg
There was brass inside the bolt, never seen or heard of this before, just wandering what's up with that.

Also, on a side note, looking to get a 12 inch rail of sort for my rifle. Would a 12' centurion c4 rail with FSB cut out work? Thinking that the FSB cut out would let the piston fit and function like before. I know the samson evo rails work but I really hate tube rails, so wondering what 12' quad rails there are.

Basically the answered I'm looking for are to the questions:
-Why won't my LWRC (Almost 100% certain it's 5.56mm, says 5.56 on the lower even) shoot this ammo
-Should I look at getting .223 instead of 5.56mm ammo? Or was it just the higher quality ammo.
-Whats up with the brass inside my bolt?
-What should I do to get my LWRC functioning like it should be?
-Centurion c4 12' rail with FSB cut out fitting on lwrc 16' m6a2?

Call LW's CS, very nice folks. Ask that set of questions on LW's forum, few experienced knowledgable guys on there. I have used a lot of Fed XM stuff and never seen that. Remember it may be brass cased but fairly sloppy blammo. It's not surplus, they cannot sell off govt. blammo .

Is that an LMT enhanced bolt?  I get brass inside the bolt too but its almost dust, not fragments like that.  what if you try cycling the ammo by hand? chamber one round and then use the charging handle to eject and rechamber?

This.

And given the fact that your extractor is tearing the rim off of every case, the brass is to be expected.  There will usually be some hint/flakes of brass in/around the bolt.

No, it's an LWRC ACB.

It's a LWRC bolt and carrier, I assure you. It's the newest version as well, no gas key or anything, the one piece dove-tail design. When cycles by hand the ammo is fine and everything ejects and feeds flawlessly for a whole mag, every time.

Cycling by hand is nothing like cycling under pressure...ask on the LWRC Forum and someone from the shop floor will give you an answer/fix.

Lwrc has a problem with the acb. They are not putting it in the new guns being built right now.

I just purchased a new spr and it came with a standard bolt.

They are working on the acb2  and when available will do an exchange.

To be correct, LWRC has recognized a problem with some manufacturer's cases (softer brass) and has a redesigned extractor due out soon for retrofit.

It's all on their forum and why a couple of us said go their first.

I had the exact same problem. It is the ACB Bolt is see in your pictures. They have been discontinued. Call LWRC and they will send you a new bolt the same day. Problem solved!

When I experienced the same problem on my M6-SL, I would take apart the bolt and clean well. After about 80 rounds the problem would come back. LWRC sent me a new bolt a few weeks back. A few hundred rounds with the new bolt...zero problems. Runs awesome. I even rapid fired 4 mags back to back on Saturday.

Well if the ACB is a problem how come I've shot multiple LWRC uppers with the ACB and numerous different types of ammo without any issues.

Apparently you haven't tried any ammo with soft enough cases to exacerbate the issue with the bolt/extractor.
Did you notice the issue appeared when the OP tried to use a particular ammo?

Joe

Same here I am at 3K plus with my ACB still no issues yet. All I shoot is either PMC, PPU Match, or LC shit.

My new M6A2 I just purchased has the standard bolt in it as well.

When the ACB2 is made available are they really going to do a swap type system?

They told me to shoot the piss out of the regular bolt and when the ACB2 was out to send it back for the new ACB2

Roger.

LWRC kicks ass!

Theres nothing worng with what your seeing. Every AR rifle strips brass. Since LWRC rifles run cleaner its easier to see the brass vs a DI gun that will have all kinds of crud and junk mixed in with the brass. Im willing to bet its the fact that the ammo your shooting wasnt built to be shot out of an auto loader. Most modern ammo has some kind of aggressive crimp so that the bullet won set back or jump forward when loaded in the chamber. Plus how was that ammo kept all these years? Was it cool and dry or wet? Those factors mean alot.

Try some other FMJ ammo and see what happens. If not call LWRC ask for Adam and he can help you

the bullet was cripmed, you can clearly see a crimp mark on the case.

good bolts wont tear off that much brass from a case.

the fact that LWRC recalled their bolts and are working on fixing issues that they admit pretty much means the ACB has issues.

The ACB had some issues and the new ACB 2 Fixes alot of them along with increasing bolt face support . Like I said give LWRC a call. They will take care of you

A couple ACBs have issues, the majority, like 99% of them do not. But LWRCI being LWRCI will not be happy until it is 100% right and they will make improvements in the process. The ACB2 is probably the nicest bolt that will hit the market. Here is a picture to give you an idea why.

ACB2 Extractor over ACB

that is nice! that extractor is a huge upgrade. my post was to souja who basically said its not the bolts fault but the brass case

OP was just unlucky enough o be one of those 1%

that should give it a lot more clamping surface!  I have been thinking of getting the LMT enhanced bolt but maybe Ill hold out for the ACB2?  I believe the price is the same for both of them

It is what it is. Shit happens. I wonder if they have reduced the spring pressure in line with the increase in clamping surface.

I have a similar issue with my LWRC M6 SPR.  1 in 50 or 1 in 100 rounds would FTE.  The next round would try to load and jam up.  After seeing your post I contacted LWRC last week and explained my problem.  They said some of the ACB's had some extractor issues and that is why they developed the ACB2.  I just got the ACB2 in the mail and will try to hit the range this weekend to see how it shoots.  I noticed the ACB2 has a bigger extractor to grab onto the case.  The finish on the bolt also appears to be different.  LWRC has excellent customer service.

Looks like soft brass.  I ran into the same issue with IMI M855 ammo.  MY PSD would rip the rim off at just about each shot.  I tested it with other brass-cased ammo (PMC X-TAC, Centurion, and Federal Mk318) without any issue.  I also had no issued with shooting WPA in it.

Try a different make ammo.  I also recommend that you contact LWRC CS and see what they say.  They hooked me up with a new standard bolt and is supposed to be sending me the ACB2 once it is ready.  Good luck!!

Because the ACB isn't the real culprit.  Some case makers decided to change the chemistry of their brass cases so that they can save some money.  What resulted is some soft cases which apparently could not hold up to the ACB.  From what I understand they are re-engineering these so that the extractor pressure is distributed over a wider surface area mitigating the torn rims.

Ammo that still use quality brass do not have issues with the ACB. FWIW.

I am not sure the brass is the only thing to blame as I shoot only PMC X-TAC and still had occasional problems.  Granted, my problem only occured 1 out of 50 rounds.

That's good. To be clear, they sent you an ACB2?  I didn't know they were out and about, but I'm happy to hear it if so.

I'd call LWRC's customer service dept.  I miss the hell out of my M6A2.  I put a ton of different types of ammo through that thing, both brass and steel and never had an issue with it.

The bolt LWRC sent me is the ACB2.  It says so on the packing slip and they told me it just came out.  It looks different then my ACB which I have to send back.

OP,if you were shooting Winchester White Box aka WWB,that's probably what the problem was. Last week at my local range,I took 100rds of that stuff to shoot in my Colt and POF & it did the same things yours did. Tried some Federal XM193 and TAP 5.56 in both guns and they ran like Swiss watches.