Hi all,

Not sure if this is the right forum, but I figured this would be alright here.  I just got done with my first two builds a few weeks ago.  Well, my first one has an SI Defense bolt carrier group in it, and the gas rings are already failing the "set it down on the table to see if it pushes in" test, and this is only after about 75 rounds.  Is there a bigger issue that could be causing this? Or should I just replace the rings and have at er? Thanks for any help!

Isaak

That is not the correct procedure, look up the TM that is available on this site.
In short there should be enough ring tension the keep the bolt from falling out of the carrier.
Even in civilian life the test is an approximation as most carbines are going to keep firing long after they fail the correct test.

Perform the test correctly and see what happens. You didn't say if you were having any function issues. If it works don't mess with it.  

NCH

Strip the BCG. remove the extractor. then insert the bolt into the carrier . then put the BCG on a head stand on the bolt face. the carrier should not drop down.

ARMY TM 9-1005-249-23&P
AIR FORCE TO 11W3-5-5-24
COAST GUARD COMDTINST M8370.9
PREVENTIVE MAINTENANCE CHECKS AND SERVICES
FOR M16/M16A1 RIFLE (Cont)
WARNING
5
Below direct support maintenance, do not interchange bolt assemblies from one
weapon to another. Doing so may result in injury to, or death of, personnel.
Quarterly
Bolt carrier assembly
(serviceability check)
Remove and disassemble. Visually in-
spect bolt assembly (1) for cracks, espe-
cially in the area of the cam pin hole (2).
Check for cracks on locking lugs (3), for
a cluster of pits or chipped bolt face
(4)
,
and for an elongated firing pin hole (5).
Check for missing or broken retaining
pin (6)/bolt cam pin (7), or cracks on bolt
cam pin.
Check for worn bolt rings (8). Insert the
bolt assembly (1) into the bolt carrier (9).
Turn bolt carrier assembly (9) so the bolt
assembly (1) points down. The bolt must
not drop out.

So no, you don't make your bolt do a head stand.

I noticed the procedure above doesn't say anything about Army or Marines. I have seen multiple people saying the test involves placing the bolt in the extended position in the carrier and to set it on a table and see if the friction between the carrier and the gas rings is enough to keep the carrier from sliding down. Is it possible the Army and Marines may have a different procedure from the one above? Just curious how this has been changed and preached as fact to many in this industry that I trust. There is a big difference between this test and the one quoted above. Anyone have any ideas?  
NCH

ARMY TM 9-1005-319-23&P
AIR FORCE TO 11 W3-5-5-42
NAVY SW370-BU-MMI-010
USMC TM 05538/10012-23&P/2
Supersedes Copy Dated August 1987

Not Fully Mission Capable If:
The bolt assembly drops out of the key and bolt carrier assembly
due to its own weight.
Missing or broken firing pin retaining pin or bolt cam pin.

Procedure:
Check for worn or missing bolt rings (6).
Check for proper staggering of bolt rings.
Insert the bolt assembly (1) into the key
and bolt carrier assembly (7). Turn key
and bolt carrier assembly (7) so the bolt
assembly (1) points down. The bolt as-
sembly must not drop out. Remove bolt
assembly (p 2-35). Check for broken or    
missing firing pin retaining pin (8) and    
bolt cam pin (9); replace as necessary.

I have not seen it all, but I have yet to see any BCG stand up to the OP’s stated test with more than few hundred rounds at most.
I have heard of it, but I don’t remember what the explanation for it being a good test was.

Thanks for the help guys.  I found the proper test, and it was just fine.