As most of you know, my stag was sent back to them for repair. (The upper)

Went down to the range today with a buddy that had an identical Stag for comparison.

It shot fine.  Did the short stroke check by putting one round in the mag and firing.  The bolt locked back fine, UNTIL...

I took the rifle off my shoulder to where the buttstock came in contact with nothing.  Basically free floating.  Bolt would not lock back.

I think I've narrowed it down to my lower, or the buffer.   I swapped buffers with his and it appeared to work perfectly.  Everytime, the bolt locked back.

Setup is...
Stag M4 complete upper
Stag stripped lower
RBP lower parts kit
Stock/buffer/spring was purchased from The Tic on the EE.  The one that he claims has sold hundreds or whatever.  Not ragging on him, just thought maybe it would click if I said that.

I replaced the spring with an ISMI spring (used at the range) but the buffer is still the same.

What kind of buffer should I replace it with and hope it works?

Also, on his Stag upper, to the left of the keyhole, he has a "C."  My Stag upper doesn't have that.  What does it mean?

As far as the buffer setup, he bought his lower complete, and his upper complete soo....

I'll have pics of my buffer up in a few.

Pictures of the buffer.

Does this pattern look right/normal?

dubisteinspundloch.com/DSCF4987.JPG

dubisteinspundloch.com/DSCF4990.JPG

in no way shape or form is that nomal.  You should have them check out your lower reciever.  On my buffers I just see a faint outline of where the carrier impacted the buffer.

EDIT:  I really like the Endine hydraulic buffers.  And about the firing it while floating, if your arms and hands moved too much with the recoil then the rearward momentum of the carrier will decrease (assuming your weights are rattling around in the buffer, if your weights are melted or whatever into the buffer then you should be having problems with bolt bounce, not short stroking)

If I were you I would seriously look over your lower to make sure the stock is affixed correctly.  As refrence i'll take a pic of mine for comparison purposes.

This gun is really starting to piss me off.  I think I might be finished with Stag.

What do you think could be causing it?  It looks like when I shot my upper on his lower, it left a nice mark on his buffer.  I don't see anything on the back of the carrier that would cause that...

ETA- Sent Stag another email.  I think they're getting sick of hearing about my gun.  If it isn't one thing, it's another.

I honestly have no idea regarding the cause.  The little cut looking thungs around the egde are problems  with the carrier stop pin though.  It seems possible that you might be shooting ammo too hot which would cause agressive movement during the feeding time and it would crunch the spring/buffer harder than normal causing it to rebound with unusual force.

EDIT: It also might be possible that your gas port is too large, allowing too much gas into the system

Quoted: in no way shape or form is that nomal.  You should have them check out your lower reciever.  On my buffers I just see a faint outline of where the carrier impacted the buffer. EDIT:  I really like the Endine hydraulic buffers.  And about the firing it while floating, if your arms and hands moved too much with the recoil then the rearward momentum of the carrier will decrease (assuming your weights are rattling around in the buffer, if your weights are melted or whatever into the buffer then you should be having problems with bolt bounce, not short stroking) If I were you I would seriously look over your lower to make sure the stock is affixed correctly.  As refrence i'll take a pic of mine for comparison purposes.

Isn't that the point to let them move with the recoil though?  It should lock back regardless right?  I held it the same way with his though and it did fine.

The weights still rattle around.

I'm really curious though what the hell is eating up my buffer.

Quoted: I honestly have no idea regarding the cause.  The little cut looking thungs around the egde are problems  with the carrier stop pin though.  It seems possible that you might be shooting ammo too hot which would cause agressive movement during the feeding time and it would crunch the spring/buffer harder than normal causing it to rebound with unusual force. EDIT: It also might be possible that your gas port is too large, allowing too much gas into the system

All I have shot is WWB 55gr FMJ .223, Winchester Q3131 5.56mm, and Federal American Eagle .223.

Stag should have examined the gas port when they looked at the thing in the first place.  That was the main reason I sent it back because there was abnormal carbon buildup around the end of the gas tube.

This pic is before I sent the rifle back to them.  Haven't looked at it afterwards, but it's the same gas tube I can tell, and it wasn't removed because the same messed up roll pin is still there.

dubisteinspundloch.com/Gast%20ube/DSCF4927.JPG

dubisteinspundloch.com/Gast%20ube/DSCF4928.JPG

Here are the pics of the buffer tube.

dubisteinspundloch.com/buffer%20tube/

In my noob impression, it looks like your buffer is smacking really hard against the retnetion pin.

One quick check...check the length of your buffer spring and make sure it's a carbine length and not rifle length.

Quoted: In my noob impression, it looks like your buffer is smacking really hard against the retnetion pin. One quick check...check the length of your buffer spring and make sure it's a carbine length and not rifle length.

It's pretty long, but C4 Grant said it's supposed to be like that and he uses them in all his rifles.  It's the carbine length ISMI spring.

What about all the swirls in the center though?

Just to add, I have never lubricated the buffer/spring or tube.

After shooting, I have always cleaned the bore, scrubbed and lubricated the upper and all components of it.  I usually don't bother with the lower except for a light coat on the fire control parts.

Why would putting his BUFFER ONLY in my gun make the difference?  It appeared to work perfectly with only his buffer swapped.

My lower would not lock the bolt back on his gun either.

And I'm still curious why his upper has a "C" stamped to the left of the keyhole and mine doesn't.

Holy shit is this service or what...

+2 for Stag!  Now if this one gets beat up, I'll look into it further from there.

By the way, I sent this email about a half hour ago.

Chris we have had many failures with non mil spec buffers they rub on the inside of the tube and slow the carrier down to make it short stroke. You have found your problem. To help you fix the problem please e-mail me your address we will send you a mil spec buffer and your gun should run without issue. Sales

I found this kind of funny.  The email subject I sent was "problem with my Stag lower."

The email I received above, had this subject.

"RE: Problem with YOUR NON STAG BUFFER"

There's a thread around here with a buffer chewed up around the edges like yours(but worse). It looks to me like your buffer is contacting the retaining pin after firing. You should check that your carrier moves your buffer away from the pin when closing the upper/lower together with pivot pin in.

Quoted: There's a thread around here with a buffer chewed up around the edges like yours(but worse). It looks to me like your buffer is contacting the retaining pin after firing. You should check that your carrier moves your buffer away from the pin when closing the upper/lower together with pivot pin in.

How do I check that?  And how would I fix it if so?

ETA - It looks like it is.  Looked in there with a flashlight while it was almost closed.  It isn't much, but it doesn't appear to be touching.

People gather parts, build a gun themselves and then blame or at least complain to the manufacturer when all their parts don't work right.

You would think manufacturers get tired of this kind of thing.

Sounds like you might get a free "H" buffer out of the deal.

the swirls of the face of the buffer are from a little burr on the edge of your bolt carrier.
take a small file and smooth it out.

if you don't you will get the same swirl on the face of the new buffer that Stag may send you.

Those "The Tic" "RRA" buffer assemblies / stocks are JUNK. I bought one thinking it was "RRA" as the first piece to my very first AR build not knowing any better and luckily I was able to return it for a real RRA stock / buffer assembly from legaltransfers. Night and day difference between the two products. The damned Tic biffer tube wasn't even profiled properly to retain the buffer retaining pin and still close properly. Also, as you've noticed, the buffer itself is not hard anodized and is JUNK. I'd suggest apoligizing to Stag, removing the POS you now have on there, and buy a name brand stock / buffer tube from Stag or other.

Also, haven't there been some issues with RBP LPK's or am I not remembering correctly? Why would you not go with the CMT LPK?

Quoted: Quoted: There's a thread around here with a buffer chewed up around the edges like yours(but worse). It looks to me like your buffer is contacting the retaining pin after firing. You should check that your carrier moves your buffer away from the pin when closing the upper/lower together with pivot pin in. How do I check that?  And how would I fix it if so? ETA - It looks like it is.  Looked in there with a flashlight while it was almost closed.  It isn't much, but it doesn't appear to be touching.

As you close the recievers together you can feel the upper pushing in the buffer, not much, just 1/16" or so. It's a noticable amount of tension.